ERK and p38MAPK combine to improve survival in patients with BRAF mutant colorectal cancer.
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ABSTRACT: Background
In colorectal cancer (CRC), BRAF mutations influence tumour progression. In mismatch repair-deficient (dMMR) tumours, BRAF mutations are associated with a good prognosis, whereas in MMR-competent tumours, they are detrimental. The differential expression of the downstream MAPK pathway members, which are constitutively activated in BRAF mutant patients, may account for these differences.Methods
Phosphorylation of ERK, p38MAPK and JNK was assessed by immunohistochemistry, utilising CRC tissue microarrays. A discovery cohort (n = 187) and a validation cohort (n = 801) were analysed for associations with BRAF mutations, clinicopathological characteristics and cancer-specific survival (CSS).Results
In 801 CRC patients, nuclear ERK phosphorylation (HR 0.65 95% CI 0.48-0.88, p = 0.004) and the combined nuclear pERK/p-p38 score (HR 0.61 95% CI 0.45-0.82, p = 0.001) were independently associated with CSS, and were further associated with increased BRAF mutations (p = 0.003 and p = 0.002). When stratified for BRAF status, only MMR-competent patients harbouring the mutation and a strong combined nuclear pERK/p-p38 score (HR 0.49 95% CI 0.27-0.89, p = 0.016) demonstrated improved CSS. This improvement in CSS was specific to stage III CRC (HR 0.25 95% CI 0.10-0.64, p = 0.002).Conclusions
MMR-competent stage III tumours harbouring BRAF mutations have an improved prognosis when strong nuclear phosphorylation of both ERK and p38MAPK is present.
SUBMITTER: Roseweir AK
PROVIDER: S-EPMC6070918 | biostudies-literature |
REPOSITORIES: biostudies-literature
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