Certain studies have demonstrated that the reduced ERα phosphorylation at serine 118 (pERα-S118) and the increased ERα phosphorylation at serine 167 (pERα-S167) were correlated significantly with the improved disease-free survival (DFS) and overall survival (OS) of breast cancer patients, while alternative studies have suggested a correlation between either pERα-S118 or pERα-S167 and tamoxifen resistance (5). The gene discussed is ESR1; the disease is breast cancer.