ERBB2 and breast cancer: These results are in line with those found in the literature, where PABC is described in most cases as an aggressive, high-grade carcinoma [35,43], characterized by negativity for hormone receptors, with reduced frequency of luminal subtypes and a higher occurrence of HER2 and triple-negative carcinomas [44], as reported by Suelmann et al. on a large Dutch cohort (20% vs. 10% for HER2 positive BC and 33.8% vs. 22% for TNBC).