Immunohistochemical studies on uterine tumors. I. Invasive squamous cell carcinomas of the cervix and their precursors.

40 invasive carcinomas and 80 preinvasive lesions of the uterine cervix were studied immunohistochemically; 40 benign lesions served as controls. On histological and immunohistochemical examination, invasive and preinvasive carcinomas were subdivided in the squamous (large cell, ectocervical) type and the reserve cell (small, large or clear cell, endocervical) type. Immunohistochemically, 100% of the invasive and preinvasive squamous cell carcinomas were positive with anticytokeratins 13, 14, 16 and negative with anticytokeratin 8 and anti-CEA. Most of the invasive and preinvasive reserve cell carcinomas showed a coexpression of cytokeratins 13, 14, 16, 8 and CEA. The subdivision of invasive carcinomas of the ecto- and endocervix into squamous cell and reserve cell types made by means of their structural differences is substantiated and re-evaluated by their immunohistochemical reactions. Both types of carcinomas retain the complex pattern of cytokeratins shown by their cells of origin. The reserve cell carcinomas, in addition, acquire a coexpression for CEA that indicates malignant transformation. The subdivision is of clinical importance because both types of carcinomas vary in their mode and speed of invasion and spread and in their association with HPV infection.