Recently, a novel form of MSI has been described that occurs only at tetranucleotide repeat markers. This has been termed elevated microsatellite instability at selected tetranucleotide repeats (EMAST). EMAST has been related to alterations of the @entity876 gene, and to the nature of the repeat sequence. We initially tested whether loss of heterozygosity (LOH) at the @entity876 and the patched (ptch) genes was related to EMAST in a series of 61 @entity1489 ( @entity1489 ) @entity5 . We then analysed a series of 57 primary @entity150 for the presence of EMAST, testing whether this was related to mutation or expression of the @entity876 gene. In both @entity1489 and @entity150 we found a high prevalence of EMAST (75.4 and 43.9%). In @entity1489 the prevalence of EMAST was higher in @entity5 that had either @entity876 or ptch LOH, although the difference was not statistically significant. There was a significant association of extensive EMAST (three or more loci) with mutations in @entity876 among the @entity150 , but no indication of elevated EMAST in @entity5 with abnormal @entity876 staining without mutation. The association of EMAST with @entity876 mutation was confined to non-invasive disease. Hence, EMAST likely reflects a particular pattern of somatic events that are interactive with @entity876 mutation, particularly common in @entity1489 and limited to non-invasive disease in @entity150 .

Microsatellite instability at tetranucleotide repeats in skin and XXXX .

@entity876 :: ('7157', 'Gene') :: ['p53'] @entity1489 :: ('MESH:D012878', 'Disease') :: ['non-melanoma skin cancer', 'NMSC', 'skin cancer'] @entity150 :: ('MESH:D001749', 'Disease') :: ['bladder cancers', 'bladder tumors', 'bladder cancer', 'bladder cancer tumors'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumors']
@entity150 :: (MESH:D001749,Disease) :: ['bladder cancer']
