BACKGROUND: DNA deficient mismatch repair (dMMR) genes are associated with @entity124 and good prognosis in early-stage @entity14 ( @entity14 ). However dMMR is rare in metastatic @entity14 (mCRC) and little is known about its influence on treatment response rate (RR). The primary objective of this study was to compare the RR of @entity1 with mCRC according to dMMR status. METHODS: This was a retrospective study that compared the RR by Response Evaluation Criteria In Solid Tumors 1.1 criteria in @entity1 with mCRC treated with chemotherapy according to dMMR status. All digital images were retrieved for RR evaluation by a single radiologist blinded to dMMR results. dMMR was defined as loss of immunohistochemistry expression of at least 1 of the MMR genes ( @entity6756 , @entity4311 , @entity4638 , or @entity14437 ). Cases were dMMR @entity1 , and controls were proficient MMR (pMMR) @entity1 (1:2 fashion). Based on clinical and molecular features, dMMR @entity1 were classified as probable Lynch or sporadic. RESULTS: From January 2009 to January 2013, 762 out of 1270 @entity1 were eligible and screened for dMMR: n  = 27 (3.5%) had dMMR mCRC and n  = 735 (96.5%) had pMMR mCRC. Given the rarity, 14 dMMR cases outside the inclusion period were included (total 41 dMMR cases) and 84 controls (pMMR). By intention-to-treat analysis, considering all @entity1 who received at least 1 dose of @entity901 -based chemotherapy (N dMMR  = 34), those with dMMR had lower RR compared with those with pMMR (RR, 11.7% vs. 28.6%; odds ratio, 0.33; 95% confidence interval, 0.08-1.40; P  = .088); @entity1 with probable Lynch-related mCRC presented higher RR than subjects with probable sporadic dMMR (22.2% vs. 0%). dMMR was associated with @entity817 mutations and poor prognosis, particularly in the sporadic subgroup (median survival, 29.8 vs. 5.9 months; P  = .025). CONCLUSION: This study suggests that the dMMR phenotype is predictive of resistance to @entity901 -based chemotherapy. Apparently, such resistance is more pronounced in the sporadic dMMR phenotype, suggesting biological heterogeneity within the dMMR mCRC subgroup.

Response to Chemotherapy and Prognosis in Metastatic XXXX With DNA Deficient Mismatch Repair.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity6756 :: ('4292', 'Gene') :: ['MLH1'] @entity901 :: ('MESH:C030110', 'Chemical') :: ['oxaliplatin'] @entity124 :: ('MESH:D053842', 'Disease') :: ['microsatellite instability'] @entity4311 :: ('4436', 'Gene') :: ['MSH2'] @entity14437 :: ('5395', 'Gene') :: ['PMS2'] @entity14 :: ('MESH:D015179', 'Disease') :: ['CRC', 'colorectal cancer'] @entity817 :: ('673', 'Gene') :: ['BRAF'] @entity4638 :: ('2956', 'Gene') :: ['MSH6']
@entity14 :: (MESH:D015179,Disease) :: ['Colorectal Cancer']
