Carcinogenesis involves alteration such as insensitivity to growth inhibition, evasion of apoptosis, immortalization, angiogenesis, and metastasis, some of these alteration are genetic and provided by activation of protooncogenes or inactivation of tumor suppressors. However, other alterations involve epigenetic events and environmental factors extrinsic to the cancer cell.
癌变涉及到癌细胞生长接触抑制停止、逃避凋亡、永生化、血管生成和转移的变化。其中一些变化是可遗传的，并通过原癌基因的激活或抑癌基因的失活而产生。然而，表观遗传修饰和外在环境因子的改变等其它原因也会产生癌细胞。