Our results, however, are based on a small cohort of samples therefore further classification of subsets of CD4 + T-cells, such as the immune dampening CD4 + FOXP3 + regulatory T-cells (Tregs), in a larger population of on-treatment HER2 + breast cancer biopsy samples in the future is warranted to provide greater insight [31]. This evidence concerns the gene ERBB2 and breast cancer.