Effects of forkhead box C2 on carcinogenesis and lymphatic metastasis in endometrial carcinoma.

We investigated the distribution of endometrial lymphatic vessels and expression of forkhead box C2 (FOXC2) in normal endometrium during menstrual cycle and in endometrial adenocarcinoma. Full-thickness uterine samples and endometrial adenocarcinoma samples were collected for immunohistochemical analysis using D2-40 and FOXC2 mouse monoclonal antibodies. The lymphatic vessel density (LVD) of the endometrium was significantly reduced compared with the myometrium during the cycle. Intra-tumoral LVD was significantly decreased in both stages of endometrioid adenocarcinoma compared with normal endometrium and myometrium. Intra-tumoral LVD significantly decreased from stage IA to stage IIIC. Peri-tumoral LVD for stage IA and stage IIIC tumors was significantly increased compared with normal endometrial LVD, but decreased compared with normal myometrial LVD. Stage IIIC showed increased peri-tumoral LVD when compared with stage IA. The positive rate of FOXC2 was 73.3% in proliferative endometrium and 80% in secretory endometrium. Secretory endometrium showed significantly increased FOXC2 expression compared with proliferative endometrium. Endometrioid adenocarcinoma showed significantly increased FOXC2 expression compared with normal endometrium, both in the epithelium and stroma. FOXC2 expression in the stroma significantly increased when pelvic and/or para-aotic lymph nodes were involved. FOXC2 was immunolocalized in low-risk endometrial carcinoma in endometrioid adenocarcinoma, but not in normal endometrium. Endometrial lymphatic vessels were located in normal endometrium and myometrium across the menstrual cycle and in intra-and peri-endometrioid adenocarcinoma, and increased in endometrial adenocarcinoma. Peri-tumoral lymphatics were associated with increased lymphatic metastasis. FOXC2 may be associated with the genesis of endometrial carcinoma and lymphangiogensis in endometrial adenocarcinoma in intra- and peri-tumoral lymphatics.