Finally, our results also suggest that ER + breast cancer tumor cells, selected for resistance to Tam over 3 months, exhibit a MnSOD-K68-Ac signature, similar to results previously published, suggesting a role of MnSOD levels29–31, and/or aberrant ROS levels23,32, in endocrine resistance in ER + tumor cells. The gene discussed is SOD2; the disease is breast carcinoma.