Solid tumours are heterogeneous communities of cancer cells and cancer-supportive stromal cells; especially cancer-associated fibroblasts (CAFs).1 CAFs are identified by expression of alpha smooth muscle actin (SMA) and other contractile proteins and they secrete extracellular matrix (ECM) proteins, including periostin, fibronectin and collagen 1 (col1). The gene discussed is SMN1; the disease is cancer.