In addition to genetic epidemiology, cancer epidemiology is another branch of epidemiology that is related very closely to molecular epidemiology. In fact, the term molecular cancer epidemiology is brought to being in the early 1980s primarily because of this close interrelationship. Insofar as carcinogenesis often initiates with DNA damage, biomarkers that can be used to identify early responses to such damage are important to the assessment of cancer risk. Unscheduled DNA synthesis, chromosome aberrations, sister chromatid exchanges, and the micronucleus tests are some examples of these tumor markers. As Weinstein (1988) put it, “These markers can be scored long in advance of preneoplastic lesions that are detected by histologic methods.” Because these markers are genetic materials in nature, they are often referred to as genetic markers.

Modern cancer epidemiologists are no longer just preoccupied with the study of the effects of cigarette smoking and radiation, nowadays they are also interested in identifying and quantifying diets and other environmental contaminants as potential carcinogens. Because cytogenetic monitoring is more feasible than histologic examination for neoplastic lesions in human subjects, epidemiological data on carcinogenic effects are becoming more available for health as well as cancer risk assessment.