GPRC5A+ myCAFs promote ESCC progression via TGF-β-induced fibroblast activation and ANXA1-mediated M2 macrophage polarization

Cancer-associated fibroblasts (CAFs) play a pivotal regulatory role in the immune microenvironment of esophageal squamous cell carcinoma (ESCC), reshaping the tumor microenvironment and promoting disease progression through the secretion of various factors. Utilizing single-cell RNA sequencing (scRNA-seq) on 15 ESCC and 11 normal tissues, we identified a distinct terminally differentiated myofibroblast (myCAF_1) subset that was significantly expanded in tumors and correlated with poor patient prognosis. This subpopulation was specifically marked by GPRC5A, a gene we validated as a myCAF_1-specific marker through bulk transcriptomic deconvolution of large cohorts. Functional studies revealed that GPRC5A⁺ myCAFs drive ESCC progression via a dual mechanism: (1) Activating the TGF-β/SMAD2/3 pathway to promote the transformation of normal fibroblasts (NFs) into CAFs, and (2) Secreting ANXA1 to recruit monocytes and polarize them into M2-type tumor-associated macrophages (TAMs), thereby fostering an immunosuppressive microenvironment. These findings were confirmed using primary CAFs and NFs models. Our study unveils GPRC5A as a key mediator in ESCC and proposes the GPRC5A/TGF-β/ANXA1 axis as a promising therapeutic target for ESCC treatment.