Luminal cell lines highly express luminal epithelium genes, but neither basal epithelial nor stromal markers; on the contrary, triple-negative BC cell lines show a basal-like phenotype (9 out of 15 as quantified in Supplementary Table 03) with the expression of at least one of keratin 5, 14 or 1728,29, with triple-negative subtype B cell lines also expressing vimentin (VIM) and Collagen Type VI Alpha Chains (COL6A1, COL6A2, COL6A3)21. This evidence concerns the gene COL6A2 and breast cancer.