Immunophenotype of male breast cancer: ER positive 99cases, accounting for 93.40%; PR positive 98cases, accounting for 92.45%; HER2 IHC 0 for 23 cases, HER2 IHC 1 + for 27 cases, HER2 IHC 2 + for 51 cases, HER2 IHC 3 + for 5 cases; HER2-null 10 cases, HER2 ultra-low 13 cases, HER2 low 72 cases, HER2-positive 11 cases, HER2-positive rate 10.38%, the incidence of low-expression 67.93%, the incidence of ultra-low expression 12.26%. This evidence concerns the gene ESR1 and breast cancer.