Vitamin D receptor and cellular retinol-binding protein-1 immunohistochemical expression in normal, hyperplastic and neoplastic endometrium: Possible diagnostic and therapeutic implications
We conducted this study to assess the effect of VDR and CRBP-1 immunohistochemical expression on the endometrium and to explore their role in endometrial cancer carcinogenesis. This study comprised two hundred paraffin-embedded endometrial tissue samples diagnosed as 42 and 63 proliferative and secretory endometrium respectively, 45 endometrial hyperplasias with atypia and 50 endometrial carcinomas (25 low-grade and 25 high-grade endometrial carcinomas). The immunohistochemical method was done to determine the expression of VDR and CRBP-1. VDR was strongly expressed in 8 (17.8%) cases with endometrial hyperplasia, 15 (60%) cases with low-grade endometrial carcinoma, and 22 (88%) cases with high-grade endometrial carcinoma. While CRPB1 overexpression was noted in cases with proliferative endometrium, secretory endometrium and endometrial hyperplasia with atypia, 37 (88.1%), 56 (88.9%) and 3 (6.7%) cases respectively and all malignant cases showed negative expression. Increased VDR expression and reduced CRBP-1 expression are associated with malignant features of the endometrium with a significant statistical difference of immunoreactivity between groups of normal endometrium, hyperplastic changes & carcinoma. Our data suggested that increased VDR expression is partly associated with endometrial cancers through a premalignant phase. Also, increased VDR and reduced CRBP-1 expression are associated with the progression of endometrial carcinoma with higher grades.