Advances in carcinogenesis: a historical perspective from observational studies to tumor genome sequencing and TP53 mutation spectrum analysis.

Tumor sequencing projects have been initiated over the last decade with the promising goal of identifying novel cancer genes and potential therapeutic targets. One of the unexpected findings of these projects was the discovery that cancer genomes contain thousands of passenger mutations that are irrelevant to tumor development and are coselected by a small number of driver mutations that constitute the true selection power in cancer progression. Although often discarded and considered to be irrelevant, the value of passenger mutations should not be underestimated, as they are the most important markers of the exposure to various carcinogens and are essential to assess the etiology of individual tumors. Over the last century, the history of cancer epidemiology evolved in different stages and concepts from occupational observational studies beginning in the 18th century, in vitro and in vivo experimental analyses and cancer gene analyses, such as Ha-ras or TP53. Mutation spectra of passenger mutations from various types of cancers not only confirm the findings of molecular epidemiology analysis, but also reveal novel profiles that will extend this knowledge to single tumors in all types of cancer.