ESR1 and breast cancer: Moreover, we show here that SAMD4A is negatively correlated (r = −0.44, p < 0.0001) with ERα mRNA levels in ERα+ BCs, and accordingly, it was reported to be repressed in BC tissues and cancer cell lines where its low expression is associated with the poor survival of patients and its overexpression inhibited tumor angiogenesis and cancer progression [57].