The candidate tumour suppressor gene, ING1, is retained in colorectal carcinomas.

ING1 plays a critical role in regulating cell cycle progression and susceptibility to apoptosis. The present study aimed to investigate allelic deletion of, and mutations within, the ING1 gene in colorectal carcinomas. Genomic DNA was extracted from 29 sporadic colorectal carcinomas and samples of adjacent normal mucosa. Losses of heterozygosity of two polymorphic dinucleotide repeat markers close to the ING1 locus at chromosome 13q32-34 were analysed. Single-stranded conformational polymorphisms of polymerase chain reaction amplified regions within the coding sequence of ING1 were examined. Microsatellite instability was noted in 5 (17%) colorectal carcinomas; this confirms selection of a subject sample representative of the population. Neither losses of heterozygosity nor changes in electrophoretic mobility of single-stranded polymerase chain reaction products were detected in any colorectal carcinoma. Thus, in common with tumour suppressor genes such as RB and BRCA2 on chromosome 13q, ING1 appears to be retained intact in colorectal carcinomas.