Interestingly, several reports have shown that loss of miR-199a was found to causethe elevated expression of DDR1in hepatocellular carcinoma [20], leukemia [28], colorectal cancer [29], cutaneous squamous cell carcinoma [30], breast cancer [43] and ovarian cancer [44], suggesting that miR-199a has a critical role in DDR1 regulation. This evidence concerns the gene DDR1 and breast cancer.