SLFN5 and neoplasm: In contrast to the reported positive effects of SLFN5 and SLFN12 in breast cancer, high SLFN11 expression correlates with more aggressive breast cancer tumors with signs of immune activation (basal-like phenotype, higher histological grade, younger age), while lower SLFN11 expression is noted in the luminal, less aggressive neoplasms characterized by low immune activation [17].