ERBB2 and breast cancer: The most striking morphological feature distinguishing the TP53 germline carriers was the presence of a densely sclerotic tumour stroma (Figure 1) reported in 29 of 36 (80.6%) of cases, compared with 28 of 55 (50.9%) of young patients with HER2 positive breast cancer with no germline TP53 pathogenic variant (p = 0.004) and lower still in other groups; 50 of 138 BRCA1 carriers (36.2%, p < 0.001), 65 of 157 BRCA2 carriers (41.4%, p < 0.001) and 95 of 217 in YBC (43.8%, p < 0.001) (Table 3 and Figure 2).