Familial risks in cervical cancer: Is there a hereditary component?

The Swedish Family-Cancer Database was used to analyze familial relationships in mothers and daughters in invasive and in situ cervical cancers from years 1958-1994, including a total of 125,000 in situ and 14,000 invasive cancers. In situ cancers were diagnosed on average 10 years earlier than invasive cancers. Familial relative risks (FRRs) were calculated separately for mothers and daughters, and were between 1.8 and 2.3 for the 2 forms. The risks were only slightly modified by age of onset, except at higher ages where there was no familial risk; in mothers, the risks increased if more than one daughter was affected. Aggregation of in situ cases among sisters was observed in families. Heritability estimates were between 0.11 and 0.15 for in situ and 0.22 and 0.34 for invasive cervical cancer. A comparison of cancers in mothers and daughters showed an association between cervical cancer and many cancer types observed in immunosuppressed patients, suggesting a role for a mild form of immunosuppression, in addition to sexual behavior leading to human-papilloma-virus infections, in familial cervical cancer.