ESR1 and neuroendocrine carcinoma: Immunohistochemistry revealed that the NEC components in both endometrial and cervical tumors were strongly immunoreactive for CD10, positive for CD56, weakly positive for synaptophysin and p16, and negative for estrogen receptor (ER), progesterone receptor (PgR), carcinoembryonic antigen (CEA), and chromogranin (Fig. 3a-e).