To determine possible effects of α3(V) ablation on mammary carcinomas, Col5a3−/− and MMTV-PyMT mice were intercrossed to obtain Col5a3−/−/MMTV-PyMT (KO/PyMT) and Col5a3+/+/MMTV-PyMT (WT/PyMT) progeny (Supplementary Fig. 1a). This evidence concerns the gene COL5A3 and breast carcinoma.