Of these, MATN3, SMOC2, LAMB2, LAMA2, JAM2, JAM3, ECM2, DCN, and COL8A2 were exclusively downregulated in TNBC compared to ER+ breast cancer, and their expressions were significantly downregulated in basal-like breast cancers compared to normal-like, ER+, and/or HER2+ breast cancers (Fig. 5d). This evidence concerns the gene ECM2 and breast cancer.