Stromal COL12A1 defines a pro-invasive extracellular matrix niche in appendiceal mucinous neoplasms and pseudomyxoma peritonei

COL12A1 is prominently upregulated in the stromal compartment of appendiceal mucinous neoplasms and pseudomyxoma peritonei, where it supports CAF-driven invasion.

• Why it matters: PMP progression involves extensive mucus accumulation and peritoneal dissemination, but the stromal extracellular matrix cues that enable invasion and metastatic niche formation are poorly defined.
• What they did: The study profiled extracellular matrix niche from PMP patient samples, used 3D matrix models to test invasion versus ECM composition, and performed CAF co-culture with COL12A1 silencing.
• The result: Collagen/fibronectin-rich environments promoted invasion, while selected SLRPs attenuated it; metastatic lesions showed increased collagen deposition, density, and alignment, and COL12A1-expressing CAFs enhanced invasion.