For each gene, high expression, as seen in 26bk/d cells, was significantly associated with increased rates of recurrence (Figure 7; log rank, TNKS1BP1 p = 0.002, CPSF7 p = 0.007, COL12A1 p = 0.043), implicating them, and by inference miR-26b, as stromal determinants of breast cancer outcome. This evidence concerns the gene COL12A1 and breast cancer.