ESR1 and breast cancer: In ERα-positive breast cancer patients, there was a positive correlation between low LLGL2 mRNA expression and longer DFS and OS (P = 0.0009 and P = 0.005, respectively; Supplementary Fig. S1c,d); however, in ERα-negative breast cancer patients, there was no association between LLGL2 mRNA expression and prognosis (Supplementary Fig. S1e,f).