Abstract
Numerous problems are encountered in human cancer genetic investigations ranging from the emotional, related to cultural or societal differences, to the primary psychological, where the fear of cancer may be rampant. Compounding the issue even further is the medical complexity of the cancer problem. Specifically, accurate diagnosis, where pathological verification is mandatory, must be attained, in order to appraise specific anatomical sites of cancer predilection in patients and their relatives. Until recently, therefore, considerably more attention has been given to cancer genetics at the infrahuman level. In considering the problem of carcinogenesis, cancer epidemiologists must take into account every conceivable epidemiological clue which might be contributing even in a small way to the problem. The patient must be viewed in context with genetic and nongenetic factors and their interactions, and the physician must relate these complex issues to each specific histological variety of cancer when he studies cancer incidence and prevalence in a specific population; he must appraise not only the genetic background, including racial factors, family history, and degree of consanguinity, but he must also scrutinize critically the patients' environmental exposures. The latter includes X rays, actinic radiation, abnormalities in soil content, animal and floral characteristics indigenous to the particular area and the social, economic and psychological peculiarities and dietary idiosyncrasies of the patient(s). Over 40 Mendelian inherited cancer and precancerous disorders have now been identified. The present study relates the author's experience in cancer genetics in a variety of these problems and provides a detailed catalog of inherited cancer and precancerous disorders.