AIM:To analyze the correlation between the protein expression of p16 and Rb genes in gastric carcinoma (GC), to investigate the role of p16 gene in invasion and lymph node metastasis of GC, and to examine the deletion...AIM:To analyze the correlation between the protein expression of p16 and Rb genes in gastric carcinoma (GC), to investigate the role of p16 gene in invasion and lymph node metastasis of GC, and to examine the deletion and mutation in exon 2 of p16 gene in GC. METHODS: The protein expression of p16 and Rb genes was examined by streptavidin-peroxidase conjugated method (S-P) in normal gastric mucosa, dysplastic gastric mucosa and GC. The deletion and mutation of p16 gene were examined by polymerase chain reaction (PCR) and polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) respectively in normal gastric mucosa and GC. RESULTS: The positive rates of P16 and Rb protein expression respectively were 96% (77/80) and 99% (79/80) in normal gastric mucosa, 92% (45/50) and 80% (40/50) in dysplastic gastric mucosa, 48% (58/122) and 60% (73/122) in GC. The positive rates of P16 and Rb protein expression in GC were significantly lower than that in normal gastric mucosa and dysplastic gastric mucosa (P<0.05). The positive rate of P16 protein expression in mucoid carcinoma (10%, 1/10) was significantly lower than that in poorly differentiated carcinoma (51%, 21/41), undifferentiated carcinoma (58%, 15/26) and signet ring cell carcinoma (62%, 10/16) (P<0.05). The positive rates of P16 protein in 30 cases of paired primary and lymph node metastatic GC were 47% (14/30) and 17% (5/30) respectively, being significantly lower in the later than in the former (P<0.05). There was no mutation in exon 2 of p16 gene in the 25 freshly resected primary GCs. But five cases in the 25 freshly resected primary GCs displayed deletion in exon 2 of p16 gene. The positive rate of both P16 and Rb proteins was 16% (14/90), and the negative rate of both P16 and Rb proteins was 8% (7/90) in 90 GCs. The rate of positive P16 protein with negative Rb protein was 33% (30/90). The rate of negative P16 protein with positive Rb protein was 43% (39/90). There was reverse correlation between P16 and Rb expression in 90 GCs CONCLUSION: The loss protein expression of p16 and Rb genes is related to GC. The loss expression of P16 protein is related to the histopathologic subtypes and lymph node metastasis of GC. Expression of P16 and Rb proteins in GC is reversely correlated. The deletion but not mutation in exon 2 of p16 gene may be involved in GC.展开更多
INTRODUCTIONHepatocellular carcinoma (HCC) is one of the mostcommon human malignancies worldwide[1,2], and isclosely associated with infection of HBV and HCVand contamination of aflatoxin B1[3-6]. Althoughthe molecula...INTRODUCTIONHepatocellular carcinoma (HCC) is one of the mostcommon human malignancies worldwide[1,2], and isclosely associated with infection of HBV and HCVand contamination of aflatoxin B1[3-6]. Althoughthe molecular mechanisms of hepatocarcinogenesisremain poorly understood, an increasing number ofgenetic abnormalities have been recognized[7-10],for example, the p16 gene[11,12] the p53gene[13-18], the E-cadherin gene[19], and the c-mycgene[20].展开更多
AIM: To explore the association of methylation of the CpG island in the promotor of the p16 tumor suppressor gene with the clinicopathological characteristics of the colorectal cancers. METHODS: Methylation-specific P...AIM: To explore the association of methylation of the CpG island in the promotor of the p16 tumor suppressor gene with the clinicopathological characteristics of the colorectal cancers. METHODS: Methylation-specific PCR (MSP) was used to detect p16 methylation of 62 sporadic colorectal cancer specimens. RESULTS: p16 methylation was detected in 42% of the tumors.Dukes'staging was associated with p16 methylation status.p16 methylation occurred more frequently in Dukes'C and D patients (75.9%) than in Dukes'A and B patients (12.1%). CONCLUSION: p16 methylation plays a role in the carcinogenesis of a subset of colorectal cancer, and it might be linked to poor prognosis.展开更多
Objective To study the alterations of FHIT gene and P16 gene in malignant transformed human bronchial epithelial cells induced by crystalline nickel sulfide using an immortal human bronchial epithelial cell line, and ...Objective To study the alterations of FHIT gene and P16 gene in malignant transformed human bronchial epithelial cells induced by crystalline nickel sulfide using an immortal human bronchial epithelial cell line, and to explore the molecular mechanism of nickel carcinogenesis. Methods 16HBE cells were treated 6 times with different concentrations of NiS in vitro, and the degree of malignant transformation was determined by assaying the anchorage-independent growth and tumorigenicity. Malignant transformed cells and tumorigenic cells were examined for alterations of FHIT gene and P16 gene using RT-PCR, DNA sequencing, silver staining PCR-SSCP and Western blotting. Results NiS-treated cells exhibited overlapping growth. Compared wkh that of negative control cells, soft agar colony formation efficiency of NiS-treated cells showed significant increases （P〈0.01） and dose-dependent effects. NiS-treated cells could form tumors in nude mice, and a squamous cell carcinoma was confirmed by histopathological examination. No mutation of exon 2 and exons 2-3, no abnormal expression in pl6 gene and mutation of FHIT exons 5-8 and exons 1-4 or exons 5-9 were observed in transformed cells and tumorigenic cells. However, aberrant transcripts or loss of expression of the FHIT gene and Fhit protein was observed in transformed cells and tumorigenic cells. One of the aberrant transcripts in the FHIT gene was confirmed to have a deletion of exon 6, exon 7, exon 8, and an insertion of a 36 bp sequence replacing exon 6-8. Conclusions The FHIT gene rather than the P16 gene, plays a definite role in nickel carcinogenesis. Alterations of the FHIT gene induced by crystalline NiS may be a molecular event associated with carcinogen, chromosome fragile site instability and cell malignant transformation. FHIT may be an important target gene activated by nickel and other exotic carcinogens.展开更多
Aberrations of chromosome 9 p21 22 are involved in the genesis of many forms of cancer.The gene p16 and p15 have been assigned to this region.Both p16 and p15 are an inhibitor of cycli...Aberrations of chromosome 9 p21 22 are involved in the genesis of many forms of cancer.The gene p16 and p15 have been assigned to this region.Both p16 and p15 are an inhibitor of cyclin D cdk4,cyclin D cdk6 complex and have been implicated in a wide variety of cancer types,including the germline of patients with familial melanoma.In order to investigate and compare the status of p16,p15 gene in primary tumors and cell lines,we examined 357 primary tumors and 29 cell lines derived from diverse tumor types.In addition to analysis of these primary tumors and cell lines,blood specimens from 91 patients either with sporadic multiple cancers or from cancer prone families were also analyzed.The data showed the following:1)Homozygous deletions of p16,p15 were comparatively rare and far less common than previously reported,although hemizygous deletions were observed in a significant fraction of many tumor types;2)the incidence of p16,p15 deletions(either homozygous deletions or heterozygous deletions)varied significantly among different tumor types;3)most deletions involved in both p16 and p15 genes;4)sequence variations in the coding sequence of p16,p15 were comparatively rare among these tumor types,though mutations and polymorphisms were identified;5)some tumors which showed LOH at 9p,containing p16 and p15 gene,did not show deletions or point mutations in the p16,p15 gene.6)In a subset of retinoblastoma and osteosarcoma where no Rb gene mutations were present a significant fraction was found to contain p16,p15 gene deletions.展开更多
Objective： To investigate the relationship between the genetic polymorphism of CYP1A1 and the genetic susceptibility to lung cancer as well as to study the effects of the methyiation in p16 gene on the risk of lung c...Objective： To investigate the relationship between the genetic polymorphism of CYP1A1 and the genetic susceptibility to lung cancer as well as to study the effects of the methyiation in p16 gene on the risk of lung cancer in a Chinese population. Methods： A case control study was conducted among 47 cases of lung cancer and 94 controls. The genetic polymorphism of CYP1A1 was tested with method of PCR-RFLP, and a methylation-specific PCR （MSP） was performed to detect p16 methylation. Results： It showed that there was no significant difference in frequencies of the genotypes of CYP1A1 between the two groups （P 〉 0.05）. Synergistic effects were not found between smoking and CYP1AI. Methylated p16 gene was found in 44.7% （21/47） of lung cancer tissues and in 17.0% （8/47） of normal lung tissues with significant difference （P 〈 0.05）. Conclusion： The genetic polymorphism of CYP1A1 does not increase the risk of lung cancer in a Chinese population. The methylation in p16 gene may be the most common mechanism to inactivate p16 gene in lung cancer, and is not significantly associated with genotype of CYP1A1,展开更多
Objective： To analyze the aberrant methylation of p16 gene and DAPK gene in sera from primary liver cancer patients ad to evaluate the clinical significance. Methods： A methylation-specific PCR was performed for the...Objective： To analyze the aberrant methylation of p16 gene and DAPK gene in sera from primary liver cancer patients ad to evaluate the clinical significance. Methods： A methylation-specific PCR was performed for the detection of promoter hypermethylation of p16 gene and DAPK gene in blood DNA from 64 cases of HCC patients, and to analyze the relation of the aberrant methylation of p16 gene and KAPK gene and the clinical pathological data. Results： 76.6%（49/64） of the sera from 64 cases of HCC patients showed hypermethylation for p16 promoter and 40.6% （26/64） for KAPK promoter, whereas no methylated p16 gene promoter and DAPK gene promoter were found in sera from benign liver diseases patients and normal control. Methylated p16 gene and KAPK gene promoters in sera did not strongly correlated with HBsAg, stage, metastasis and differentiation in HCC; but strongly correlated with AFP. Conclusion： Detection of the aberrant methylation of p16 gene and KAPK gene in blood DNA from HCC patients might offer an effective means for the earlier auxiliary diagnosis of the malignancy.展开更多
The effects of exogenous p16^ink4a gene on biological behaviors of human lung cancer cell line with homozygous deletion of p16^ink4a gene were investigated. Exogenous p16^ink4a gene was transfected by lipofectin into ...The effects of exogenous p16^ink4a gene on biological behaviors of human lung cancer cell line with homozygous deletion of p16^ink4a gene were investigated. Exogenous p16^ink4a gene was transfected by lipofectin into human lung cell line A549, in which p16^ink4a gene was homozygously deleted. The expression of p16^ink4a mRNA and protein was detected by RT-PCR and immunocytochemistry, respectively. The changes in the behaviors of the transfected cell lines in vitro and in vivo were observed. In the transfected cell line A549, the exogenous p16^ink4a gene could be stably expressed. The growth of A549 cells transfected with p16^ink4a gene was obviously slowed down. Flow cytometry revealed that transfection of the exogenous p16^ink4a gene resulted in A549 cell lines arrest in G1 phase of cell cycle. The tumorigenicity of these transfected cells in nude mice could be inhibited, and the tumor growth of nude mice was significantly suppressed. It was concluded that exogenous p16^ink4a gene may be stably expressed in human lung cancer cell line A549. The expression of the introduced p16^ink4a could block lung cancer cells to entry into S phase of cell cycle and inhibit tumor malignant growth both in vitro and in vivo.展开更多
The expression of P16 gene were found in all 3 groups. The positive unit (PU) was higher in tumor group and cancer group than that in normal group ( P <0.01). Furthermore, the PU of P16 was stronger in cytopla...The expression of P16 gene were found in all 3 groups. The positive unit (PU) was higher in tumor group and cancer group than that in normal group ( P <0.01). Furthermore, the PU of P16 was stronger in cytoplasm than in nucleus. Malignant tumors and acini surrounding the tumor revealed strong positives and week positives respectively. The PU of P16 gene was higher in deep lobe of recurrent parotid neoplasm with incomplete capsule than that in shallow lobe of primary parotid neoplasm with complete capsule. Our findings suggests that P16 gene plays equally important role in the salivary gland tumors and tumors in other part of the body.展开更多
AIM:To further understand the molecular basis for gastric cardia carcinogenesis and to provide etiological clues. METHODS: Endoscopic mucosa biopsy and histopathological examinations were made on 37 subjects from a hi...AIM:To further understand the molecular basis for gastric cardia carcinogenesis and to provide etiological clues. METHODS: Endoscopic mucosa biopsy and histopathological examinations were made on 37 subjects from a high incidence area for both esophageal and gastric cardia carcinomas in northern China. All the biopsy samples were fixed in 850 ml. (-1)L alcohol and embedded in paraffin. Each block contained one piece of tissue and was serially section at 5 microm. Immunohistochemistry (ABC) was carried out on these gastric cardia samples to determine the alterations of p16 and Rb. RESULTS: Based on the histopathlogical examination there were 11 cases of chronic superficial gastritis, 12 cases of chronic atrophic gastritis and 14 cases of dysplasia. The immunostaining demonstrated different levels of unclear immunostaining of p16 and Rb in normal gastric cardia tissue and the tissues with different severity of lesions. With the lesions progressing, the positive immunostaining rates for p16 protein had a decreasing tendency. In contrast, the positive immunostaining rate for Rb protein had an increasing tendency. There was a significant negative relationship between the two parameters. Changes of p16 was CSG 11(100%), CAG 7(58%), DYS 4(29%) and changes of Rb was CSG 2(18%), CAG 8(67%) and DYS 12(86%), (P【0.05). CONCLUSION: The alterations of p16 and Rb protein may play a role in the early stages of gastric cardia carcinogenesis.展开更多
Objective: To detect promoter hypermethylation of p16 gene in matched pre- and post-operative plasma of patients with gastric adenocarcinoma for evaluating the effectiveness of therapeutic intervention. Methods: Tissu...Objective: To detect promoter hypermethylation of p16 gene in matched pre- and post-operative plasma of patients with gastric adenocarcinoma for evaluating the effectiveness of therapeutic intervention. Methods: Tissue samples, pre- and post-operative plasma of 84 patients were collected. Plasma of 15 healthy people was collected as control. After sodium-bisulfite treatment, extracted DNA was amplified for p16 promoter by methylation-specific polymerase chain reaction (MSP). The PCR products were detected by both gel-ethidium bromide electrophoresis and high performance liquid chromatogram (HPLC). Results: Among 84 patients, p16 hypermethylation was detected in 26 (31.0%) cancer tissues and 2 (0.02%) tumor-adjacent tissues and 12 (14.3%) pre-operative plasma, while negative in plasma of healthy people. For positive plasma cases, the paired tumor tissues were confirmed to be methylated. Within available 30 pairs of matched pre- and post-operative plasma, 6 pre-operative plasma was positive, and only 1 of 6 plasma remained hypermethylated after surgery. The results detected by HPLC exactly matched those by gel-electrophoresis. Conclusion: The alteration of status of p16 hypermethylation in post-operative plasma is considered the consequences of surgical intervention. Although p16 hypermethylation has no role in pre-operative staging of gastric cancer, detecting hypermethylated p16 in plasma could be utilized in monitoring patients after surgery.展开更多
Objective: To investigate the possible relationship between deletion of MTS/p16 gene and progression of endometrial carcinoma Methods: Forty six primary endometrial carcinoma, 7 tumor adjacent endometrial tissue,...Objective: To investigate the possible relationship between deletion of MTS/p16 gene and progression of endometrial carcinoma Methods: Forty six primary endometrial carcinoma, 7 tumor adjacent endometrial tissue, 10 normal endometrial tissue specimen and 5 xenografts from patients with endometrial carcinoma were examined for homozygous deletion of MTS/p16 gene by polymerase chain reaction based analysis Results: Of 46 endometrial cancer specimens, 9 showed homozygous deletion, no deletion was detected in the tumor adjacent and normal endometial tissues Nor was it detected in well differentiated endometrial carcinoma and all xenografts Conclusions: Deletion of MTS1/p16 gene might contribute to the progression of endometrial carcinoma and could be served as indicator for predicting prognosis展开更多
Objective: To examine the occurrence of p16 gene deletion and to analyze p16 expression on paraffin-embedded human pituitary adenoma specimens. Efforts were made to optimize the technical conditions forin situ PCR. Me...Objective: To examine the occurrence of p16 gene deletion and to analyze p16 expression on paraffin-embedded human pituitary adenoma specimens. Efforts were made to optimize the technical conditions forin situ PCR. Methods:In situ PCR techniques and inimuno-histochemistry were used. Results: Immunohistochemically, p16-positive tumor cells were observed in all cases with various proportions. The majority of the stromal cells and part of tumor cells was devoid of p16 immunostaining, but signal ofin situ PCR for p16 gene, exon 2, was displayed in these cells. Conclusion: The results implied that p16 gene might not be deleted in these pituitary adenomas. It also indicated thatin situ PCR, both direct and indirect methods, proved feasible and informative to the aim of DNA detection. It is critical to overcome non-specific amplification in directin situ PCR by means of higher annealing temperature, fewer cycle, lower magnesium concentration and stringent washing. A target DNA-deleted sample as the negative control is extremely necessary. For the indirect method, the way to improve the sensitivity is to loosen the conditions for amplification and washing, so that more amplification products are subject to hybridization, and signal detection is facilitated.展开更多
Objective: To determine the effects on the cell growth, tumorigenicity and chemosensitivity of p16/CDK4I in human glioma. Methods: p16 gene was transfected into U251 cells by lipofectin. Expression of exogenous p16 ge...Objective: To determine the effects on the cell growth, tumorigenicity and chemosensitivity of p16/CDK4I in human glioma. Methods: p16 gene was transfected into U251 cells by lipofectin. Expression of exogenous p16 gene was confirmed by immunohistochemistry and Northern blot. The effects of exogenous p16 gene on the growth and chemosensitivity to teniposide were examined. Results: Expression of exogenous p16 gene inhibited the growth dramatically in vitro. G1 arrest of tumor cells was observed. However, wt p16-positive U251 was less sensitive than control cell lines and the number of apoptotic cells after chemotherapy was reduced. Conclusion: The expression of exogenous p16 gene could inhibit the growth of glioma. On the other hand, the chemosensitivity to teniposide of p16-positive U251 was decreased.展开更多
基金Supported by the Grant From the Education Committee of Hunan Province, No. 97B095, No. 01B016 the grant from the Health Bureau of Hunan Province, No. 9301, the Key Programs during the 8th 5-Year Plan Period, the Bureau of Health, Hunan Province, China
文摘AIM:To analyze the correlation between the protein expression of p16 and Rb genes in gastric carcinoma (GC), to investigate the role of p16 gene in invasion and lymph node metastasis of GC, and to examine the deletion and mutation in exon 2 of p16 gene in GC. METHODS: The protein expression of p16 and Rb genes was examined by streptavidin-peroxidase conjugated method (S-P) in normal gastric mucosa, dysplastic gastric mucosa and GC. The deletion and mutation of p16 gene were examined by polymerase chain reaction (PCR) and polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) respectively in normal gastric mucosa and GC. RESULTS: The positive rates of P16 and Rb protein expression respectively were 96% (77/80) and 99% (79/80) in normal gastric mucosa, 92% (45/50) and 80% (40/50) in dysplastic gastric mucosa, 48% (58/122) and 60% (73/122) in GC. The positive rates of P16 and Rb protein expression in GC were significantly lower than that in normal gastric mucosa and dysplastic gastric mucosa (P<0.05). The positive rate of P16 protein expression in mucoid carcinoma (10%, 1/10) was significantly lower than that in poorly differentiated carcinoma (51%, 21/41), undifferentiated carcinoma (58%, 15/26) and signet ring cell carcinoma (62%, 10/16) (P<0.05). The positive rates of P16 protein in 30 cases of paired primary and lymph node metastatic GC were 47% (14/30) and 17% (5/30) respectively, being significantly lower in the later than in the former (P<0.05). There was no mutation in exon 2 of p16 gene in the 25 freshly resected primary GCs. But five cases in the 25 freshly resected primary GCs displayed deletion in exon 2 of p16 gene. The positive rate of both P16 and Rb proteins was 16% (14/90), and the negative rate of both P16 and Rb proteins was 8% (7/90) in 90 GCs. The rate of positive P16 protein with negative Rb protein was 33% (30/90). The rate of negative P16 protein with positive Rb protein was 43% (39/90). There was reverse correlation between P16 and Rb expression in 90 GCs CONCLUSION: The loss protein expression of p16 and Rb genes is related to GC. The loss expression of P16 protein is related to the histopathologic subtypes and lymph node metastasis of GC. Expression of P16 and Rb proteins in GC is reversely correlated. The deletion but not mutation in exon 2 of p16 gene may be involved in GC.
基金Project supported partly by the National Natural Science Foundation of China, No. 39870344
文摘INTRODUCTIONHepatocellular carcinoma (HCC) is one of the mostcommon human malignancies worldwide[1,2], and isclosely associated with infection of HBV and HCVand contamination of aflatoxin B1[3-6]. Althoughthe molecular mechanisms of hepatocarcinogenesisremain poorly understood, an increasing number ofgenetic abnormalities have been recognized[7-10],for example, the p16 gene[11,12] the p53gene[13-18], the E-cadherin gene[19], and the c-mycgene[20].
基金Supported by the grants from Mjnistry of Public Health of China,No.98-1-303The Educational Committee of Shanghai,No.2000B02.
文摘AIM: To explore the association of methylation of the CpG island in the promotor of the p16 tumor suppressor gene with the clinicopathological characteristics of the colorectal cancers. METHODS: Methylation-specific PCR (MSP) was used to detect p16 methylation of 62 sporadic colorectal cancer specimens. RESULTS: p16 methylation was detected in 42% of the tumors.Dukes'staging was associated with p16 methylation status.p16 methylation occurred more frequently in Dukes'C and D patients (75.9%) than in Dukes'A and B patients (12.1%). CONCLUSION: p16 methylation plays a role in the carcinogenesis of a subset of colorectal cancer, and it might be linked to poor prognosis.
基金This work was supported by a grant (No. 39170651 and 30200235) from National Natural Science Foundation of China.
文摘Objective To study the alterations of FHIT gene and P16 gene in malignant transformed human bronchial epithelial cells induced by crystalline nickel sulfide using an immortal human bronchial epithelial cell line, and to explore the molecular mechanism of nickel carcinogenesis. Methods 16HBE cells were treated 6 times with different concentrations of NiS in vitro, and the degree of malignant transformation was determined by assaying the anchorage-independent growth and tumorigenicity. Malignant transformed cells and tumorigenic cells were examined for alterations of FHIT gene and P16 gene using RT-PCR, DNA sequencing, silver staining PCR-SSCP and Western blotting. Results NiS-treated cells exhibited overlapping growth. Compared wkh that of negative control cells, soft agar colony formation efficiency of NiS-treated cells showed significant increases （P〈0.01） and dose-dependent effects. NiS-treated cells could form tumors in nude mice, and a squamous cell carcinoma was confirmed by histopathological examination. No mutation of exon 2 and exons 2-3, no abnormal expression in pl6 gene and mutation of FHIT exons 5-8 and exons 1-4 or exons 5-9 were observed in transformed cells and tumorigenic cells. However, aberrant transcripts or loss of expression of the FHIT gene and Fhit protein was observed in transformed cells and tumorigenic cells. One of the aberrant transcripts in the FHIT gene was confirmed to have a deletion of exon 6, exon 7, exon 8, and an insertion of a 36 bp sequence replacing exon 6-8. Conclusions The FHIT gene rather than the P16 gene, plays a definite role in nickel carcinogenesis. Alterations of the FHIT gene induced by crystalline NiS may be a molecular event associated with carcinogen, chromosome fragile site instability and cell malignant transformation. FHIT may be an important target gene activated by nickel and other exotic carcinogens.
文摘Aberrations of chromosome 9 p21 22 are involved in the genesis of many forms of cancer.The gene p16 and p15 have been assigned to this region.Both p16 and p15 are an inhibitor of cyclin D cdk4,cyclin D cdk6 complex and have been implicated in a wide variety of cancer types,including the germline of patients with familial melanoma.In order to investigate and compare the status of p16,p15 gene in primary tumors and cell lines,we examined 357 primary tumors and 29 cell lines derived from diverse tumor types.In addition to analysis of these primary tumors and cell lines,blood specimens from 91 patients either with sporadic multiple cancers or from cancer prone families were also analyzed.The data showed the following:1)Homozygous deletions of p16,p15 were comparatively rare and far less common than previously reported,although hemizygous deletions were observed in a significant fraction of many tumor types;2)the incidence of p16,p15 deletions(either homozygous deletions or heterozygous deletions)varied significantly among different tumor types;3)most deletions involved in both p16 and p15 genes;4)sequence variations in the coding sequence of p16,p15 were comparatively rare among these tumor types,though mutations and polymorphisms were identified;5)some tumors which showed LOH at 9p,containing p16 and p15 gene,did not show deletions or point mutations in the p16,p15 gene.6)In a subset of retinoblastoma and osteosarcoma where no Rb gene mutations were present a significant fraction was found to contain p16,p15 gene deletions.
基金a grant from the National Natural Sciences Foundationof China(No.30471427).
文摘Objective： To investigate the relationship between the genetic polymorphism of CYP1A1 and the genetic susceptibility to lung cancer as well as to study the effects of the methyiation in p16 gene on the risk of lung cancer in a Chinese population. Methods： A case control study was conducted among 47 cases of lung cancer and 94 controls. The genetic polymorphism of CYP1A1 was tested with method of PCR-RFLP, and a methylation-specific PCR （MSP） was performed to detect p16 methylation. Results： It showed that there was no significant difference in frequencies of the genotypes of CYP1A1 between the two groups （P 〉 0.05）. Synergistic effects were not found between smoking and CYP1AI. Methylated p16 gene was found in 44.7% （21/47） of lung cancer tissues and in 17.0% （8/47） of normal lung tissues with significant difference （P 〈 0.05）. Conclusion： The genetic polymorphism of CYP1A1 does not increase the risk of lung cancer in a Chinese population. The methylation in p16 gene may be the most common mechanism to inactivate p16 gene in lung cancer, and is not significantly associated with genotype of CYP1A1,
文摘Objective： To analyze the aberrant methylation of p16 gene and DAPK gene in sera from primary liver cancer patients ad to evaluate the clinical significance. Methods： A methylation-specific PCR was performed for the detection of promoter hypermethylation of p16 gene and DAPK gene in blood DNA from 64 cases of HCC patients, and to analyze the relation of the aberrant methylation of p16 gene and KAPK gene and the clinical pathological data. Results： 76.6%（49/64） of the sera from 64 cases of HCC patients showed hypermethylation for p16 promoter and 40.6% （26/64） for KAPK promoter, whereas no methylated p16 gene promoter and DAPK gene promoter were found in sera from benign liver diseases patients and normal control. Methylated p16 gene and KAPK gene promoters in sera did not strongly correlated with HBsAg, stage, metastasis and differentiation in HCC; but strongly correlated with AFP. Conclusion： Detection of the aberrant methylation of p16 gene and KAPK gene in blood DNA from HCC patients might offer an effective means for the earlier auxiliary diagnosis of the malignancy.
基金This project was supported by a grant from the Science Research Foundation of Hubei Province, China (No. 98J102).
文摘The effects of exogenous p16^ink4a gene on biological behaviors of human lung cancer cell line with homozygous deletion of p16^ink4a gene were investigated. Exogenous p16^ink4a gene was transfected by lipofectin into human lung cell line A549, in which p16^ink4a gene was homozygously deleted. The expression of p16^ink4a mRNA and protein was detected by RT-PCR and immunocytochemistry, respectively. The changes in the behaviors of the transfected cell lines in vitro and in vivo were observed. In the transfected cell line A549, the exogenous p16^ink4a gene could be stably expressed. The growth of A549 cells transfected with p16^ink4a gene was obviously slowed down. Flow cytometry revealed that transfection of the exogenous p16^ink4a gene resulted in A549 cell lines arrest in G1 phase of cell cycle. The tumorigenicity of these transfected cells in nude mice could be inhibited, and the tumor growth of nude mice was significantly suppressed. It was concluded that exogenous p16^ink4a gene may be stably expressed in human lung cancer cell line A549. The expression of the introduced p16^ink4a could block lung cancer cells to entry into S phase of cell cycle and inhibit tumor malignant growth both in vitro and in vivo.
文摘The expression of P16 gene were found in all 3 groups. The positive unit (PU) was higher in tumor group and cancer group than that in normal group ( P <0.01). Furthermore, the PU of P16 was stronger in cytoplasm than in nucleus. Malignant tumors and acini surrounding the tumor revealed strong positives and week positives respectively. The PU of P16 gene was higher in deep lobe of recurrent parotid neoplasm with incomplete capsule than that in shallow lobe of primary parotid neoplasm with complete capsule. Our findings suggests that P16 gene plays equally important role in the salivary gland tumors and tumors in other part of the body.
基金the National Natural Science Foundation of China,No,39770296
文摘AIM:To further understand the molecular basis for gastric cardia carcinogenesis and to provide etiological clues. METHODS: Endoscopic mucosa biopsy and histopathological examinations were made on 37 subjects from a high incidence area for both esophageal and gastric cardia carcinomas in northern China. All the biopsy samples were fixed in 850 ml. (-1)L alcohol and embedded in paraffin. Each block contained one piece of tissue and was serially section at 5 microm. Immunohistochemistry (ABC) was carried out on these gastric cardia samples to determine the alterations of p16 and Rb. RESULTS: Based on the histopathlogical examination there were 11 cases of chronic superficial gastritis, 12 cases of chronic atrophic gastritis and 14 cases of dysplasia. The immunostaining demonstrated different levels of unclear immunostaining of p16 and Rb in normal gastric cardia tissue and the tissues with different severity of lesions. With the lesions progressing, the positive immunostaining rates for p16 protein had a decreasing tendency. In contrast, the positive immunostaining rate for Rb protein had an increasing tendency. There was a significant negative relationship between the two parameters. Changes of p16 was CSG 11(100%), CAG 7(58%), DYS 4(29%) and changes of Rb was CSG 2(18%), CAG 8(67%) and DYS 12(86%), (P【0.05). CONCLUSION: The alterations of p16 and Rb protein may play a role in the early stages of gastric cardia carcinogenesis.
基金This work was supported in part byScience Research Foundation of Peking University Schoolof Oncology(00-01and04-01)
文摘Objective: To detect promoter hypermethylation of p16 gene in matched pre- and post-operative plasma of patients with gastric adenocarcinoma for evaluating the effectiveness of therapeutic intervention. Methods: Tissue samples, pre- and post-operative plasma of 84 patients were collected. Plasma of 15 healthy people was collected as control. After sodium-bisulfite treatment, extracted DNA was amplified for p16 promoter by methylation-specific polymerase chain reaction (MSP). The PCR products were detected by both gel-ethidium bromide electrophoresis and high performance liquid chromatogram (HPLC). Results: Among 84 patients, p16 hypermethylation was detected in 26 (31.0%) cancer tissues and 2 (0.02%) tumor-adjacent tissues and 12 (14.3%) pre-operative plasma, while negative in plasma of healthy people. For positive plasma cases, the paired tumor tissues were confirmed to be methylated. Within available 30 pairs of matched pre- and post-operative plasma, 6 pre-operative plasma was positive, and only 1 of 6 plasma remained hypermethylated after surgery. The results detected by HPLC exactly matched those by gel-electrophoresis. Conclusion: The alteration of status of p16 hypermethylation in post-operative plasma is considered the consequences of surgical intervention. Although p16 hypermethylation has no role in pre-operative staging of gastric cancer, detecting hypermethylated p16 in plasma could be utilized in monitoring patients after surgery.
文摘Objective: To investigate the possible relationship between deletion of MTS/p16 gene and progression of endometrial carcinoma Methods: Forty six primary endometrial carcinoma, 7 tumor adjacent endometrial tissue, 10 normal endometrial tissue specimen and 5 xenografts from patients with endometrial carcinoma were examined for homozygous deletion of MTS/p16 gene by polymerase chain reaction based analysis Results: Of 46 endometrial cancer specimens, 9 showed homozygous deletion, no deletion was detected in the tumor adjacent and normal endometial tissues Nor was it detected in well differentiated endometrial carcinoma and all xenografts Conclusions: Deletion of MTS1/p16 gene might contribute to the progression of endometrial carcinoma and could be served as indicator for predicting prognosis
基金a grant from Ministry of Public Health of China!(98-l-303)
文摘Objective: To examine the occurrence of p16 gene deletion and to analyze p16 expression on paraffin-embedded human pituitary adenoma specimens. Efforts were made to optimize the technical conditions forin situ PCR. Methods:In situ PCR techniques and inimuno-histochemistry were used. Results: Immunohistochemically, p16-positive tumor cells were observed in all cases with various proportions. The majority of the stromal cells and part of tumor cells was devoid of p16 immunostaining, but signal ofin situ PCR for p16 gene, exon 2, was displayed in these cells. Conclusion: The results implied that p16 gene might not be deleted in these pituitary adenomas. It also indicated thatin situ PCR, both direct and indirect methods, proved feasible and informative to the aim of DNA detection. It is critical to overcome non-specific amplification in directin situ PCR by means of higher annealing temperature, fewer cycle, lower magnesium concentration and stringent washing. A target DNA-deleted sample as the negative control is extremely necessary. For the indirect method, the way to improve the sensitivity is to loosen the conditions for amplification and washing, so that more amplification products are subject to hybridization, and signal detection is facilitated.
基金the National Natural Science Foundation of China! (No. 39700143).
文摘Objective: To determine the effects on the cell growth, tumorigenicity and chemosensitivity of p16/CDK4I in human glioma. Methods: p16 gene was transfected into U251 cells by lipofectin. Expression of exogenous p16 gene was confirmed by immunohistochemistry and Northern blot. The effects of exogenous p16 gene on the growth and chemosensitivity to teniposide were examined. Results: Expression of exogenous p16 gene inhibited the growth dramatically in vitro. G1 arrest of tumor cells was observed. However, wt p16-positive U251 was less sensitive than control cell lines and the number of apoptotic cells after chemotherapy was reduced. Conclusion: The expression of exogenous p16 gene could inhibit the growth of glioma. On the other hand, the chemosensitivity to teniposide of p16-positive U251 was decreased.
