engleski

Inbreeding and cancer incidence in human isolates

The aim of this study was to investigate the impact of inbreeding on development of cancer in isolate populations. A thorough anthropological research over the past three decades has established island populations in Middle Dalmatia, Croatia as outstanding examples of genetic isolates. The number of incident cancer cases on five islands (Brač, Hvar, Korčula, Vis and Lastovo) over the 20 year period between 1971 and 1990 has been revised for this study, according to the data of Croatian Cancer Registry. The population of coastal Dalmatia, characterized by similar environmental impacts but quite different population genetic structure, represented a control population. The leading hypothesis was that, if there were genes or gene complexes (especially with recessive inheritance) responsible for genetic susceptibility to certain types of cancer, the incidence of those cancer types should be greater in reproductively isolated island populations than in control populatian due to accumulation of such genes/gene complexes caused by inbreeding. Furthermore, the cancer incidence rates should increase along with greater reproductive isolation (i.e. greater geographic distance of islands from the mainland). After the adjustment of obtained data by sex and age, the results have entirely confirmed the hypotheses: island populations revealed greater total cancer incidence than control population for both sexes. The "excess in incidence" on the islands showed almost a linear correlation to the geographic distance from mainland. The cancer sites primarily responsible for "excess in incidence" were urinary bladder cancer in males, and breast, ovarian, brain and large bowel cancer in females, predominantly in younger age-groups.

cancer incidence; human isolates; anthropology; population genetics

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