Characterisation of a subtype of colorectal cancer combining features of the suppressor and mild mutator pathways.

摘要: BACKGROUND: 10% of sporadic colorectal cancers are characterised by a low level microsatellite instability (MSI-L). These not thought to differ substantially from microsatelite-stable (MSS) cancers, but MSI-L and MSS distinguished clinicopathologically in their spectrum genetic alterations showing high (MSI-H). AIMS: To study the distribution molecular series stratified DNA instability. METHODS: A subset an unselected was grouped finding MSI at 0 loci (n = 51), 1-2 (MSI-L) 38) 3-6 (MSI-H) 25). The frequency K-ras mutation, loss heterozygosity (LOH) 5q, 17p 18q, patterns p53 beta catenin immunohistochemistry determined three groups. RESULTS: MSI-H had mutation (7%), LOH on chromosomes 5q (0%), (0%) 18q (12.5%), normal pattern immunostaining for catenin. differed terms higher (54% v 27%) (p 0.01) lower (23% 48%) 0.047). Whereas aberrant expression were concordant (both present or both absent) 57% concordance observed only 20% 0.01). CONCLUSIONS: distinct cancers. This combines features suppressor mutator pathways, may be more dependent than APC gene early stages neoplastic evolution, proportion related histogenetically serrated (hyperplastic) polyp.