8/20 lncRNAs of the TCGA ER+ luminal A cluster were associated with the extra-cellular matrix (S9b Table), and all achieved significant correlation with at least one of two established cancer-associated fibroblast (CAF) markers: fibroblast activation protein (FAP) and actin, alpha 2, smooth muscle, aorta (ACTA2; S9b Table). The gene discussed is ACTA2; the disease is cancer.