Introduction/Background Chlamydia trachomatis (C. trachomatis) salpingitis causes inflammatory damage to the fallopian tube, the suggested origin of most high grade serous cancers (HGSC), and could thereby cause initiation and progression of ovarian cancer. Infection with C. trachomatis may stimulate production of MUC1 protein and potentially both increase or decrease anti-MUC1 antibody levels. The aim of this study was to examine if serology indicating past infection with C. trachomatis and anti-MUC1 antibodies in prospective blood samples were associated with HGSC.

Methodology In a prospective nested case-control study within the Northern Sweden Health and Disease Study (NSHDS) and the Northern Sweden Maternity Cohort (NSMC), the prevalence of chlamydial and anti-MUC1 antibodies was analyzed in blood samples drawn more than one year prior to diagnosis from 92 women with HGSC and 363 matched controls. Matching factors were age and date at blood draw. Plasma C. trachomatis IgG was analyzed using a MIF-test (Focus Diagnostics), chlamydial HSP60 (cHSP60) and anti-MUC1 IgG were analyzed using ELISA serology (Medac; Thermo-Fisher Scientific). HGSC diagnosis was confirmed by pathology report review.

Data were analyzed using Chi-square test, Fisher’s exact test and Mann-Whitney U test. Correlation analysis was done by Spearman’s correlation test. A two-sided P-value less than 0.05 was considered significant.

Results The prevalence of C. trachomatis IgG and cHSP60 IgG antibodies, as well as the level of anti-MUC1 IgG in women with HGSC compared with controls were similar (16.3% vs. 17.0%, p=0.867; 27.3% vs 28.5%, p=0.802; median 0.24 vs 0.25, p=0.700). A significant correlation was found between anti-MUC1 IgG and cHSP60 IgG (r=0.169; p< 0.001).

Conclusion There were no significant association between chlamydial or anti-MUC1 IgG antibodies and HGSC in this prospective nested case control study.

Disclosure This work was supported by grants from The Cancer Research Foundation in Northern Sweden, and The County Council of Västerbotten, Sweden.