Deficient DNA mismatch repair is associated with favorable prognosis in Thai patients with sporadic colorectal cancer.
World J Gastroenterol
; 21(3): 926-34, 2015 Jan 21.
Article
em En
| MEDLINE
| ID: mdl-25624727
ABSTRACT
AIM:
To determine the prognostic significance of deficient mismatch repair (dMMR) and BRAF V600E in Thai sporadic colorectal cancer (CRC) patients.METHODS:
We studied a total of 211 out of 405 specimens obtained from newly diagnosed CRC patients between October 1, 2006 and December 31, 2007 at Siriraj Hospital, Mahidol University. Formalin-fixed paraffin-embedded blocks of CRC tissue samples were analyzed for dMMR by detection of MMR protein expression loss by immunohistochemistry or microsatellite instability using polymerase chain reaction (PCR)-DHPLC. BRAF V600E mutational analysis was performed in DNA extracted from the same archival tissues by two-round allele-specific PCR and analyzed by high sensitivity DHPLC. Associations between patient characteristics, MMR and BRAF status with disease-free survival (DFS) and overall survival (OS) were determined by Kaplan-Meier survival plots and log-rank test together with Cox's proportional hazard regression.RESULTS:
dMMR and BRAF V600E mutations were identified in 31 of 208 (14.9%) and 23 of 211 (10.9%) tumors, respectively. dMMR was more commonly found in patients with primary colon tumors rather than rectal cancer (20.4% vs 7.6%, P =0.01), but there was no difference in MMR status between the right-sided and left-sided colon tumors (20.8% vs 34.6%, P = 0.24). dMMR was associated with early-stage rather than metastatic disease (17.3% vs 0%, P = 0.015). No clinicopathological features such primary site or tumor differentiation were associated with the BRAF mutation. Six of 31 (19.3%) samples with dMMR carried the BRAF mutation, while 17 of 177 (9.6%) with proficient MMR (pMMR) harbored the mutation (P = 0.11). Notably, patients with dMMR tumors had significantly superior DFS (HR = 0.30, 95%CI 0.15-0.77; P = 0.01) and OS (HR = 0.29, 95%CI 0.10-0.84; P = 0.02) compared with patients with pMMR tumors. By contrast, the BRAF V600E mutation had no prognostic impact on DFS and OS.CONCLUSION:
The prevalence of dMMR and BRAF V600E in Thai sporadic CRC patients was 15% and 11%, respectively. The dMMR phenotype was associated with a favorable outcome.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Colorretais
/
Adenocarcinoma
/
Biomarcadores Tumorais
/
Reparo de Erro de Pareamento de DNA
Tipo de estudo:
Etiology_studies
/
Observational_studies
/
Prognostic_studies
Limite:
Aged80
País/Região como assunto:
Asia
Idioma:
En
Revista:
World J Gastroenterol
Assunto da revista:
GASTROENTEROLOGIA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Tailândia