COL1A1 and neoplasm: One lineage, the TGFβ-responsive myofibroblast CAF population, is located in the tumor nests, originates from stellate cells, and generates ECM mRNAs and TGFβ-induced genes such as Col1A1, Col5A1, Ctgf, smooth muscle α-2 actin (Acta2), or vimentin (Vim) [39,68,369,370].