Loss of heterozygosity on 10q and mutational status of PTEN and BMPR1A in colorectal primary tumours and metastases

We investigated the possible role of chromosome 10q losses in colorectal cancer metastasis by carrying out an allelic imbalance study on a series of microsatellite instability-negative (MSI−) primary tumours (n=32) and metastases (n=36) from 49 patients. Our results demonstrate that 10q allelic losses are associated with a significant proportion (25%) of MSI− colorectal tumours, but are not involved in the metastatic process. PTEN and BMPR1A, two genes located in the common deleted region, were screened for mutations in samples with loss of heterozygosity. The absence or low frequency of mutations indicates that the inactivation of these genes by deletion of one allele and mutation of the other one plays only a minor role in MSI− tumours.