HLA class I expression and HPV-16 sequences in premalignant and malignant lesions of the cervix

A series of 10 normal cervix epithelia, 38 condylomas, 17 CIN (cervical intraepithelial neoplasm) I/II (low-grade CIN), 10 CIN III (high-grade CIN), 27 squamous cell carcinomas and 7 adenocarcinomas of the cervix were studied in paraffin-embedded sections for the expression of MHC class I antigens, using antibodies against HLA antigens and the immunoperoxidase technique. A PCR technique was also used to evaluate the presence of HPV-16 DNA. All samples from normal tissue, benign, premalignant and CIN III lesions expressed HLA class I antigens. However, 15% of the invasive carcinomas completely lacked HLA-B and HLA-C antigen expression, 20% presented a heterogeneous pattern and 2 cases lacked HLA-B and HLA-C heavy chain but retained beta 2-microglobulin. MHC class I antigen expression on tumors was compared with clinical-pathological parameters. The absence of expression of HLA class I molecules was significantly associated with the Glanz histoprognostic index of malignancy. HPV-16 sequences were detected in 60% of the condylomas, 88% of the CIN I/II, 80% of the CIN III and 82% of the cervical carcinomas. Eight-six per cent of the tumors expressing HLA class I antigen presented HPV-16, whereas only 40% of the nonexpressing tumors did. Our results lead us to the following conclusions: a) HLA class I losses occurred when the tumor became invasive, and in tumors of a more aggressive histological type; b) The presence of HPV-16 was associated with tumors expressing HLA class I antigens.