[Genetic background in carcinogenesis]

Abstract

Carcinogenesis comprises both genetic and environmental factors. The genetic factor for cancer is most closely associated with familial cancer. Familial cancer makes up only a few percent of total cancer cases. Recently, various candidate genes for familial cancer have been identified by analyzing patients' family histories and genetically testing them. Most of these cancer susceptibility genes are frequently mutated or deleted on sporadic cancer cells. The study of these genes is very useful for explaining the molecular mechanisms of non-familial cancer. Various polymorphic mutations exist in normal phenotypes in human. Most of them are single nucleotide polymorphisms (SNPs) and intronic variations, but sometimes they are large gene alterations or chromosomal abnormalities. Human genetic polymorphisms can now be more easily analyzed by using computed biotechnology (DNA tips, microarray). Detailed examination of human DNA polymorphisms will advance the study of genetic background in carcinogenesis in the future.