One useful anti-cancer drug can effectively erase the whorls(萝状指纹)and other characteristic marks that give people their distinctive fingerprints．Losing them could become troublesome．A case (51) online in a letter by Annals of Oncology indicates how big a (52) losing finger prints is． Eng-Huat Tan，a Singapore-based medical doctor describes a 62-year-old man who has used capecitabine(卡培他滨)to (53) his nasopharyngeal cancer(鼻咽症)．After three years on the (54) ，the patient decided to visit his U．S．relatives last December．But he was stopped by U．S． customs officials (55) 4 hours after entering the country when those officials couldn't get finger prints from the man．There were no (56) swirly(旋涡状的)marks appearing from his index fin ger． U．S．customs has been fingerprinting incoming foreign visitors for years，Tan says．Unfortunately， for the Singaporean traveler，one potential (57) effect of his drug treatment is a smoothing of the tissue on the finger pads． (58) ，no fingerprints． “It is uncertain when fingerprint (59) will begin to take place in patients who are taking capecitabine，”Tan points out．So he (60) any physicians who prescribe the drug to provide their patients with a doctor's (61) pointing Out that their medicine may cause fingerprints to disappear． Eventually，the Singaporean traveler made it into the United States．But he's also now got the explanatory doctor's note-and won't leave home (62) it． By the way，maybe the Food and Drug Administration， (63) approved use of the drug 11 years ago，should consider updating its list of side effects (64) with this medicine．The current list does note that patients may experience vomiting(呕吐)，stomach pain and some other side effects． But no where (65) it mention the potential for loss of fingerprints．