ERBB2 and breast cancer: Consistently, these studies found that densities of TIICs in HR+ breast cancer were relatively low and of little prognostic relevance: A meta-analysis by Mao et al. consisting of 22,964 patients concluded that high densities of TIICs in TNBC and Her2+/HR- BC served as a prognostic marker for improved DFS, whilst the HR+ subgroup remained without significant results [6].