To predict whether midasin expression was associated with differences in RFS, KM Plotter was used to interrogate publicly available microarray repositories for ER+ and ER- breast cancer patients. We chose to stratify patients based on hormone receptor status because our LTLT-Ca model of letrozole resistance is hormone independent (40) and reflects patients within this population as they progress to metastatic disease. The gene discussed is ESR1; the disease is breast carcinoma.