ERBB2 and breast cancer: Even though we observed that NSMCE2 expression is reduced by SE blockade in all the breast cancer cell lines tested, we decided to use TN breast cancer cells, MDAMB231, BT549 and Hs578T, and the HER2 + cells HCC1954 for our experiments, since we found that high NSMCE2 gene expression levels significantly associate with poor response to chemotherapy for patients diagnosed with TN or HER2 + breast cancer.