Marker for predicting breast cancer immunotherapy effect, kit and application

The invention belongs to the field of biological medicine, and particularly relates to a marker for predicting breast cancer immunotherapy effect, a kit and application. More specifically, the present invention relates to a marker for predicting the efficacy of a breast cancer immunotherapy wherein the breast cancer is HER2 positive breast cancer or HER2 low expression breast cancer, the immunotherapy is anti-HER2 antibody therapy, and the biomarker is SHCBP1. The invention further relates to a reagent for detecting the expression of the SHCBP1, a kit containing the reagent and application of the reagent for predicting the breast cancer immunotherapy effect. The invention also relates to application of the reagent for inhibiting the expression of the SHCBP1 in enhancing the breast cancer treatment effect of the anti-HER2 antibody. It has been found that the expression level of the SHCBP1 is related to the breast cancer treatment effect of the anti-HER2 antibody, and therefore the SHCBP1 can be used for predic