Biopsy confirmed a neuroendocrine tumor (Figure 4) with immunohistochemical profile (G2 grade, Ki-67 ∼5%): SSTR2(+), Rb(+), P53 (wild expression pattern), Melan-A(−), HMB45(−), CD56(+), CgA(+), S100(−), SOX-10(−), Syn(+), E-cad(cell membrane positive), CEA[P](+), CEA[M](+), CK(+). The gene discussed is CEACAM5; the disease is neuroendocrine neoplasm.