K-ras mutations (codon 12) are not involved in down-regulation of MHC class-I genes in colon carcinomas.
Fifty-eight colorectal carcinomas were studied for HLA class-I antigen expression and for the presence of point mutations in codons 12 and 61 of the K-ras gene. Eight carcinomas were completely negative for class I by the APAAP technique. Analyses using the polymerase chain reaction (PCR) method, together with selective hybridization using mutation-specific synthetic oligonucleotides, demonstrated K-ras mutations in 14 cases (24.1%), all of them in codon 12. None of the mutations corresponded to the negative cases for class-I HLA antigen expression. We did not observe any correlation between K-ras mutations and the extent of tumor differentiation.
Servicio de Análisis Clínicos e Inmunología, Hospital Virgen de las Nieves, Granada, Spain.
M R
MR
Oliva
T
T
Cabrera
J
J
Esquivias
M
M
Perez-Ayala
M
M
Redondo
F
F
Ruiz-Cabello
F
F
Garrido
D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D003062:Codon; D003110:Colonic Neoplasms / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics*; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005805:Genes, MHC Class I; D011905:Genes, ras; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger
D003062:Codon; D015395:Histocompatibility Antigens Class I; D012333:RNA, Messenger