AIMS: The aim of this study was to assess the independent value of pathological criteria in the diagnosis of mismatch repair (MMR)-defective sporadic @entity14 . METHODS AND RESULTS: Resected @entity14 (n = 273) were reviewed in order to identify a number of specific morphological features of @entity5527 . Of the 273 cases, 35.2% were right-sided and 5.9% were poorly differentiated. Focal extracellular mucin secretion was seen in 5.1% of cases and a stromal follicular reaction in 4.6%. The expression of the two major MMR proteins @entity6756 and @entity4311 was studied by immunohistochemistry. @entity189 were considered @entity5527 when a loss of nuclear signal in neoplastic cells was observed for one of the proteins. Such an extinction was seen in 37 of the cases (13.6%). The @entity6756 protein was the one most frequently altered (86.5%). After multivariate analysis, three independent factors were significantly associated with @entity5527 : proximal location [odds ratio (OR) = 9.30; 95% confidence interval (CI) 2.79, 30.98], the presence of a true stromal follicular reaction (OR = 13.60; 95% CI 2.98, 62.00) and poor differentiation (OR = 8.33; 95% CI 1.63, 40.32). CONCLUSIONS: These results confirm that sporadic colorectal MMR-defective @entity420 display certain specific morphological characteristics. However, these pathological features are not sufficiently predictive and immunohistochemistry is needed to identify such @entity5 accurately.

Sporadic @entity14 with defective mismatch repair display a number of specific morphological characteristics: relationship between the expression of XXXX and @entity4311 proteins and clinicopathological features of 273 @entity420 .

@entity6756 :: ('4292', 'Gene') :: ['hMLH1'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumours'] @entity189 :: ('MESH:D002277', 'Disease') :: ['Carcinomas'] @entity4311 :: ('4436', 'Gene') :: ['hMSH2'] @entity5527 :: ('MESH:C536928', 'Disease') :: ['MMR-defective carcinomas', 'MMR deficiency', 'deficient in the MMR system'] @entity14 :: ('MESH:D015179', 'Disease') :: ['colorectal cancers', 'colorectal adenocarcinomas'] @entity420 :: ('MESH:D000230', 'Disease') :: ['adenocarcinomas']
@entity6756 :: (4292,Gene) :: ['hMLH1']
