Small bowel adenocarcinoma phenotyping, a clinicobiological prognostic study

T. Aparicio, M. Svrcek, A. Zaanan, E. Beohou, A. Laforest, P. Afchain, Emmanuel Mitry, J. Taieb, F. Di Fiore, J. M. Gornet, A. Thirot-Bidault, I. Sobhani, D. Malka, T. Lecomte, C. Locher, F. Bonnetain, P. Laurent-Puig

Research output: Contribution to journalArticlepeer-review

94 Scopus citations

Abstract

Background:Small bowel adenocarcinoma (SBA) is a rare tumour with a poor prognosis. Molecular biology data on SBA carcinogenesis are lacking.Methods: Expression of HER2, β-catenin, p53 and mismatch repair (MMR) protein was assessed by immunohistochemistry. KRAS, V600E BRAF mutations and microsatellite instability were investigated.Results:We obtained samples from 63 SBA patients (tumour stages: I-II: 30%; III: 35%; IV: 32%; locally advanced: 3%). HER2 overexpression (3+) was observed in 2 out of 62 patients, overexpression of p53 in 26 out of 62, abnormal expression of β-catenin in 12 out of 61, KRAS mutation in 21 out of 49, BRAF V600E mutation in 1 out of 40 patients, MMR deficiency (dMMR) in 14 out of 61 and was consistent with Lynch syndrome in 9 out of 14 patients. All of the dMMR tumours were in the duodenum or jejunum and only one was stage IV. Median overall survival (OS) was 36.6 months (95% CI, 26.9-72.2). For all patients, in univariate analysis, stages I-II (P<0.001), WHO PS 0-1 (P=0.01) and dMMR phenotype (P=0.02) were significantly associated with longer OS. In multivariate analysis, disease stage (P=0.01) and WHO PS 0-1 (P=0.001) independently predicted longer OS. For stage IV patients, median OS was 20.5 months (95% CI: 14.6; 36.6 months). In multivariate analysis, WHO PS 0-1 (P=0.0001) and mutated KRAS status (P=0.02) independently predicted longer OS.Conclusion:This large study suggests that molecular alterations in SBA are closer to those in colorectal cancer (CRC) than those in gastric cancer, with low levels of HER 2 overexpression and high frequencies of KRAS mutations. The seemingly higher frequency of dMMR than in CRC may be explained by the higher frequency of Lynch syndrome in SBA patients. A dMMR phenotype was significantly associated with a non-metastatic tumour (P=0.02). A trend for a good prognosis and a duodenum or jejunum primary site was associated with dMMR.

Original languageEnglish
Pages (from-to)3057-3066
Number of pages10
JournalBritish Journal of Cancer
Volume109
Issue number12
DOIs
StatePublished - 10 Dec 2013
Externally publishedYes

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