Are women with endocervical adenocarcinoma at risk for lynch syndrome? Evaluation of 101 cases including unusual subtypes and lower uterine segment tumors.

It is well documented that endometrial and ovarian carcinoma are associated with Lynch syndrome (LS), but the association, if any, between endocervical carcinoma and LS has not been fully evaluated. The relationship between endocervical carcinoma and LS is particularly relevant, given the apparent affinity of LS-associated endometrial carcinomas for the lower uterine segment and the attendant difficulties in determining tumor origin at this site. In this study, we examined mismatch repair (MMR) protein expression (MLH1, MSH2, MSH6, and PMS2) in 60 endocervical adenocarcinomas, including variants (minimal deviation adenocarcinoma, mesonephric adenocarcinoma, adenosquamous carcinoma, clear cell carcinoma) and a series of well-characterized lower-uterine segment carcinomas of known endocervical or endometrial origin (n=41). Two of the lower uterine segment tumors occurred in risk-reducing hysterectomy specimens from known LS patients. All endocervical adenocarcinomas including variants and lower uterine segment endocervical tumors (1 from a known LS patient) were proficient in all 4 MMR proteins. In contrast, 2/20 (10%) lower uterine segment endometrial cancers were deficient in at least 1 MMR (1 from a known LS patient). These data provide evidence that, unlike endometrial and ovarian adenocarcinoma, there is no association between LS and endocervical carcinoma. MMR testing is prudent in lower uterine segment tumors in women with possible LS, especially those for which definitive site of origin cannot be determined.