Published in Cancer Detection and Prevention 1997; 21(5):412-417.

Lack of Correlation Between Codon 12 K- Ras Mutations and Major Histocompatibility Complex Antigens in Bronchogenic Carcinomas

Maximino Redondo, MDa, Fernando Rodriguez, MDb, Maria Luisa Hortas, MDb, Angel Concha, MDc, Miguel Morell, MDd, Fededco Garrido, MDb, and Francisco Ruiz-Cabello, MDb

aDepartment of Biochemistry, Costa del Sol Hospital, Marbella, Malaga, Spain; Departments of bImmunology and cPathology, Virgen de las Nieves General Hospital, University of Granada, Spain; dDepartment of Biochemistry, University of Malaga, Spain

Address all correspondence and reprint requests to: Maximino Redondo, MD, Department of Biochemistry. Costa del Sol Hospital, Marbella 296000, Malaga, Spain.

ABSTRACT: In experimental Systems, an association between K-ras activity and expression of major histo- compatibility complex (MHC) molecules has been reported. In this study, 52 surgically resected bronchogenic carcinomas were studied for human leukocyte antigen (HLA) class I and II expression, and for the presence of point mutations in codon 12 of the K-ras gene. HLA class I loss was detected in 18 carcinomas, and most of the tumors (43 cases) were found negative for HLA class II antigen expression by the APAAP technique with specific monoclonal antibodies. Analysis using the polymerase chain reaction (PCR), together with selective hybridization using mutation-specific synthetic oligonucleotides, demonstrated K-ras mutations in five cases, all of them corresponding to the adenocarcinoma subtype (31.2% of the adenocarcinomas included in our study) with a poor degree of differentiation. We did not find any correlation between K-ras mutations and HLA class I and II expression in bronchogenic carcinomas. Therefore, it would appear that downregulation of MHC antigens by point mutations of K-ras does not take place in vivo.

KEY WORDS: bronchogenic carcinomas, K-ras, major histocompatibility antigens.