A recent study assessed the clinical, phenotypic, and molecular features of 47 neuroendocrine breast carcinomas providing evidence that the stratification of the tumors into the three different WHO groups (well-differentiated neuroendocrine tumors, poorly differentiated neuroendocrine carcinomas, and invasive breast carcinomas with neuroendocrine differentiation) did not reveal statistically significant differences in terms of progression-free survival or overall survival; in 7% of cases, PIK3CA or TP53 mutations were detected [254]. Here, PIK3CA is linked to invasive breast carcinoma.