ACTN4
Overview
ACTN4 (Alpha-Actinin-4) encodes an actin-binding cytoskeletal protein involved in cell motility and adhesion. In cancer genomics, ACTN4 has been identified as a noncanonical fusion partner with MYB in adenoid cystic carcinoma (AdCC), where chromosomal rearrangements fuse ACTN4 exons to MYB exons, producing in-frame chimeric transcripts that likely drive MYB-pathway oncogenesis.
Alterations observed in the corpus
- Noncanonical MYB fusion partner in adenoid cystic carcinoma (AdCC): ACTN4ex18::MYBex2 in-frame fusion identified in 1 metatypical nasal cavity AdCC with biphasic basaloid and vacuolated cell populations; detected by RNA-seq (TruSight Oncology 500) PMID:24418857
Cancer types (linked)
- Adenoid cystic carcinoma of the sinonasal tract: noncanonical MYB fusion partner (1/88 cases, ~1%); associated with metatypical histology featuring biphasic basaloid and vacuolated cell populations PMID:24418857
Co-occurrence and mutual exclusivity
- ACTN4::MYB fusion occurs as a noncanonical alternative to the canonical MYB::NFIB fusion; similar noncanonical partners include ACTB, EWSR1, and ESRRG PMID:24418857
Therapeutic relevance
- No targeted therapy data for ACTN4-rearranged AdCC. ACTN4::MYB fusions are expected to activate MYB transcriptional targets analogous to canonical MYB::NFIB fusions; NOTCH pathway inhibitors are being explored for the broader AdCC population PMID:24418857
Open questions
- Functional equivalence of the ACTN4::MYB fusion to the canonical MYB::NFIB fusion has not been demonstrated experimentally; the single reported case limits frequency estimation PMID:24418857
Sources
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