DNA ABERRATIONS AT THE RETINOBLASTOMA GENE LOCUS IN HUMAN SQUAMOUS-CELL CARCINOMAS OF THE LUNG

We detected DNA aberrations at the RB locus in surgical specimens of h uman primary non-small cell lung carcinoma by single-strand conformati on polymorphism analysis of polymerase chain reaction products amplifi ed from regions of exons 2 to 27 including parts of the flanking intro n sequences. Detection of nucleotide sequence polymorphism revealed lo ss of heterozygosity in six of eight informative cases among 13 squamo us cell carcinomas analysed. In two of the six cases, mutations in the remaining allele were detected. In 25 adenocarcinomas analysed, no lo ss of heterozygosity was observed in 16 informative cases and a point mutation was detected in one of the uniformative cases. In one of thre e adenosquamous carcinomas analysed, a point mutation was detected and one adenoid cystic carcinoma analysed showed allelic loss of the RB g ene. Our results indicated that loss of heterozygosity at the RB locus is frequent in squamous cell carcinomas of the lung,:but not in adeno carcinomas. In the squamous cell carcinomas with allelic loss, mutatio ns of the RB gene in the remaining alleles were found in one third of the tumors.