Observations support the theory that development of left- and right-sided colorectal cancers may involve different mechanisms. This study investigated different genes involved in oncogenesis of colon and rectal cancers and analysed their prognostic value. The study group comprised 35 colon and 42 rectal cancers. Rectal cancer patients had been treated with standardized surgery performed by an experienced rectal cancer surgeon. Mutation analysis was performed for p53 in eight colon cancers and for APC and p53 in 22 rectal cancers. MLH1, MSH2, Bcl-2, p53, E-cadherin and beta-catenin were investigated by immunohistochemistry in all colorectal tumours. APC mutation analysis of the MCR showed truncating mutations in 18 of 22 rectal tumours (82%), but the presence of an APC mutation was not related to nuclear beta-catenin expression (p=0.75). Rectal cancers showed significantly more nuclear beta-catenin than colon cancers (65% versus 40%, p=0.04). p53 mutation analysis corresponded well with p53 immunohistochemistry (p<0.001). Rectal cancers showed significantly more immunohistochemical expression of p53 than colon cancers (64% versus 29%, p=0.003). In rectal cancers, a significant correlation was found between positive p53 expression and worse disease-free survival (p=0.008), but not in colon cancers. Cox regression showed that p53-expression (p=0.03) was an independent predictor for disease-free survival in rectal cancers. This study concluded that rectal cancer may involve more nuclear beta-catenin in the APC/beta-catenin pathway than colon cancer and/or nuclear beta-catenin may have another role in rectal cancer independently of APC. The p53-pathway seems to be more important in rectal cancer, in which it also has independent prognostic value. When prognostic markers are investigated in larger series, differences in biological behaviour between colon and rectal cancer should be considered.

Summary Background Accelerated induction regimens of infliximab have been proposed to improve response rates in patients with steroid‐refractory acute severe colitis. Aim To determine the differences in outcome for acute severe ulcerative colitis between accelerated and standard‐dose infliximab Methods We collected data on hospitalised patients receiving differing regimens of rescue therapy for steroid‐refractory acute severe ulcerative colitis. Our primary outcome was 30‐day colectomy rate. Secondary outcomes were colectomy within index admission, and at 90 days and 12 months. We used propensity score analysis with optimal calliper matching using high risk covariates defined a priori to reduce potential provider selection bias. Results We included 131 patients receiving infliximab rescue therapy; 102 received standard induction and 29 received accelerated induction. In the unmatched cohort, there was no difference by type of induction in the 30‐day colectomy rates (18% vs 20%, P = .45), colectomy during index admission (13% vs 20%, P = .26) or overall colectomy (20% vs 24%, P = .38). In the propensity score‐matched cohort of 52 patients, 30‐day colectomy (57% vs 27%, P = .048) and index admission colectomy (53% vs 23%, P = .045) rates were higher in those receiving standard induction compared to accelerated induction but there was no difference in overall colectomy rates (57% vs 31%, P = .09). There was no significant difference in length of stay or in complication and infection rates. Conclusion In a propensity score‐matched cohort, steroid‐refractory acute severe ulcerative colitis patients, short‐term, but not long‐term, colectomy rates appear to be lower in those receiving an accelerated induction regimen.

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