CLDN1 and breast cancer: demonstrated that the ECM-associated genes ITGA6, COL4A1, COL4A2, COL6A1, COL6A2, LAMA1, FN1, CLDN1, GPC6, SDC2, FBN1, and FBLN1 were significantly upregulated in doxorubicin-resistant MCF-7 breast cancer cell line (68).