This is in accordance with previous studies which showed miR21 provokes myeloma cell adhesion to bone marrow stromal cells and resistance to chemotherapeutic agents [30], in addition, miR21 initiates inflammatory signaling in HER2-positive breast cancer and reduces the cytotoxic effect of neoadjuvant trastuzumab and chemotherapy [31]. This evidence concerns the gene ERBB2 and breast carcinoma.