Contribution of Immunogenetic Factors in Susceptibility to Cervical Cancer

Sammanfattning: Cervical cancer is the second most common cancer in women worldwide. Persistent infection by an oncogenic type of human papillomavirus (HPV) is a necessary but not sufficient cause and there is also a genetic component. This thesis aims to identify host genetic risk factors for cervical cancer based on the hypothesis that susceptibility is affected by genetic variation in the immune response towards HPV infection.Paper I analyzed allergy in sons and cervical cancer in their mothers, and revealed an inverse association between cervical cancer and allergy across generations. Mothers of allergic sons have a lower incidence of cervical cancer, supporting the importance of immunogenetic factors. Paper II investigated the HPV type in 1079 women diagnosed 1965-1993. All women were from families with at least two affected. It appeared that HPV 16 was becoming less common with time. There was no evidence that related women were prone to infection by the same type, indicating that the immunogenetic factors act in a general, rather than an HPV type specific, manner. Paper III and IV analysed the association of candidate genes with susceptibility to cervical cancer in 1306 women with cervical cancer in situ and 288 unrelated controls. Paper III showed the association of variation in the two immune response genes chemokine receptor 2 (CCR-2) and interleukin 4 receptor (IL-4R) with cervical cancer. In paper IV variation at several loci in the MHC region was studied and the importance of the HLA class II locus DQB1 emphasized.This thesis work supports the contribution of genes of the immune system to cervical cancer susceptibility. The genetic risk factors so far identified account for only a part of the genetic susceptibility, which implies that other yet undiscovered variants of importance remain to be identified.