FAM131B

Overview

FAM131B is a gene identified as an alternative 5’ fusion partner for BRAF in pilocytic astrocytoma. While the canonical KIAA1549:BRAF fusion accounts for the majority of pilocytic astrocytoma cases, FAM131B:BRAF represents one of a spectrum of novel BRAF fusion partners discovered by whole-genome sequencing, all converging on MAPK pathway activation.

Alterations observed in the corpus

• FAM131B:BRAF in-frame fusion identified in 1 pilocytic astrocytoma case by whole-genome sequencing (n=96); all BRAF fusions in pilocytic astrocytoma disrupt the leucine-rich negative regulatory domain and lead to constitutive BRAF kinase activation PMID:23817572

Cancer types (linked)

• Pilocytic astrocytoma — FAM131B:BRAF is one of several novel BRAF fusion partners identified in tumors lacking the canonical KIAA1549:BRAF fusion; all such fusions are predicted to activate the MAPK pathway PMID:23817572

Co-occurrence and mutual exclusivity

• Alternative 5’ fusion partner for BRAF, alongside KIAA1549 (70/96 cases), RNF130, CLCN6, MKRN1, and GNAI1 PMID:23817572

Therapeutic relevance

• BRAF fusions in pilocytic astrocytoma activate the MAPK pathway; MEK inhibition is a rational therapeutic strategy for fusion-positive tumors PMID:23817572

Open questions

• Functional validation of FAM131B:BRAF specifically (as distinct from other BRAF fusions) has not been reported PMID:23817572

Sources

• PMID:23817572

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