KERATIN EXPRESSION IN NORMAL UTERINE CERVICAL EPITHELIUM AND CARCINOMAS OF CERVICAL ORIGIN

The immunohistochemical expression of keratins 7, 8, 10, 13, 14, 17, 1 8 and 19 was examined in formalin-fixed paraffin-embedded tissues of n ormal uterine cervical epithelium and carcinomas of cervical origin (4 squamous cell carcinoma in situ, 17 squamous cell carcinoma, 9 adenoc arcinoma, and 1 adenoid basal carcinoma). A panel of 8 monoclonal anti bodies capable of recognizing 8 individual keratin subtypes was employ ed using microwave oven heating and a labeled streptavidin biotin meth od. Ectocervical squamous epithelium expressed keratins 14 and 19 in t he basal cell layer, and keratins 10 and 13 in the suprabasal cell lay er. Endocervical columnar cells were found to express keratins 7, 8, 1 8 and 19, whereas the reserve cells expressed keratins 7, 8, 14, 17, 1 8 and 19. Most of the squamous cell carcinomas, both keratinizing and non-keratinizing, as well as the carcinoma in situ revealed a keratin phenotype detected in normal ectocervical squamous cells (keratins 10, 13, 14 and 19) and endocervical subcolumnar reserve cells (keratins 7 , 17 and 18). The adenocarcinomas, both endocervical and endometrial t ype, were positive for keratins 7, 8, 17, 18 and 19. The adenoid basal carcinoma expressed all the keratins examined including the expressio n of reserve cell keratin. Reserve cell keratins were found mostly in squamous cell carcinomas, adenocarcinomas and adenoid basal carcinoma of cervical origin. Therefore, the keratin expression pattern indicate s the origin of a variety of carcinomas of the uterine cervix from a c ommon progenitor, endocervical reserve cells.