INSR and breast cancer: In this model, tumors display greater INSR but not IGF1R phosphorylation.92, 93 Accordingly, knockdown of INSR, but not IGF1R, in mammary carcinoma Mvt-1 cell line led to the considerably smaller xenografted tumors, both in wild-type and hypersinsulinemic mice.94 Similarly, in breast cancer patients, increased INSR but not IGFIR expression and higher phosphorylation of INSR/IGFIR hybrid receptors correlate with poor survival.74