MYOCD
Overview
MYOCD (Myocardin) encodes a transcriptional coactivator and master regulator of smooth muscle differentiation, acting in concert with serum response factor (SRF). In sarcoma, specifically leiomyosarcoma (LMS), MYOCD amplification at the 17p11.2-p12 locus defines a molecularly distinct and clinically worse prognostic subtype within soft tissue LMS.
Alterations observed in the corpus
- MYOCD is located at 17p11.2-p12, a recurrent amplification in LMS (known alteration); MYOCD was highly amplified in 40% (10/25) of soft tissue LMS (STLMS) iCluster C1 cases, independent of LMS type, tumor site, size, or grade (q=0.022 by GISTIC) PMID:29100075
- STLMS iCluster C1, the subgroup enriched for MYOCD amplification, had significantly worse recurrence-free survival (RFS; p=0.0002) and disease-specific survival (DSS; p=0.008) compared to C2 PMID:29100075
Cancer types (linked)
- SARC (Sarcoma) / LMS (Leiomyosarcoma): MYOCD amplification at 17p11.2-p12 defines the more aggressive STLMS iCluster C1 subtype; C1 also showed more frequent RB1 mutations, AKT pathway activation, and PTEN deletion/mutation; 84% of ULMS and STLMS C1 tumors contained AKT pathway alterations vs 44% of STLMS C2 PMID:29100075
Co-occurrence and mutual exclusivity
- MYOCD amplification co-occurs with RB1 mutations (p=0.04), MCM2 upregulation, PTEN deletion/mutation, and AKT pathway amplification in STLMS C1 PMID:29100075
Therapeutic relevance
- High AKT pathway activation in MYOCD-amplified STLMS C1 suggests potential sensitivity to PI3K/AKT/MTOR inhibitors; MTOR inhibitors everolimus and temsirolimus have shown limited but some clinical efficacy in LMS PMID:29100075
Open questions
- Whether MYOCD amplification is a functional driver of LMS aggressiveness or a passenger alteration at 17p11.2-p12 amplicons requires direct functional validation.
Sources
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