BMP3 and synovial sarcoma: Based on the identified transcriptome changes associated with the scRNA-seq findings and the gene function reported in fibrotic diseases, we hypothesized that, following environmentally triggered inflammation, salivary gland immune cells produce pro-inflammatory cytokines associated with SS (e.g., TNF-α and interferon) that activate salivary gland epithelial, endothelial and myoepithelial cells and overexpress genes such as TGFB2, WNT4, and BMP3, which are key inducers of EMT.