Heritability of cervical tumours

Development of cervical cancer is strongly associated with genital infectio n of oncogenic types of human papillomavirus (HPV). However, the majority o f women infected with HPV never develop cancer; thus, additional factors ap pear to be necessary. The relative importance of genetic and environmental factors to the development of cervical tumours is not known. Therefore, we have estimated the heritability of liability to this disease. The Swedish C ancer Register and the National Family Register were used to identify biolo gical and adoptive mothers and full, half- and adoptive sisters of cases wi th cervical tumours, as well as age-matched controls. Tetrachoric correlati ons were calculated and model fitting techniques used to estimate the relat ive importance of shared genes and shared familial environment. Shared gene s (heritability) explain 27% (95% Cl 26%-29%) of the total variation in lia bility to the disease. A significant effect of shared familiar environment was seen among sisters but not among mother/daughter relations. Sister-spec ific shared environment accounts for 2% (95% CI 1%-4%) of the variance. Our results indicate that development of cervical tumours depends, to a signif icant extent, on inherited genetic factors. Genetic predisposing factors ma y influence the likelihood of, sensitivity to or persistence of HPV infecti on, as well as the rate of tumour development. (C) 2000 Wiley-Liss, Inc.