Breast cancer cells were exposed to CM from the co-cultured Hs578Bst and BT474, BT474-STAT3(−), BT474-HIF-1α(−) or SUM102, SUM102-STAT3(−), SUM102-HIF-1α(−) cells, and it was found that miR-106a and miR-106b expression were down-regulated in the cells exposure to CM from BT474 or SUM102. Here, HIF1A is linked to breast cancer.