Noriko Kimura

Somatostatin type 2A receptor (sstr2A) has been shown to be directly involved in the transduction of antiproliferative effects and also to be the most predominant sstr subtype in human normal breast...

Primary hepatic carcinoid and neuroendocrine carcinoma (NEC) are rare tumors. We experienced three carcinoids and two NEC originating in the liver during the past 25 years and attempted to elucidate the clinicopathological and immunohistochemical features of these tumors. The patients had no endocrine symptoms despite two of them having elevated plasma serotonin. Three of the five patients died of the tumor after operation with an average survival time of 20.6 months. All tumors were large (up to 26 cm in diameter), four of them solitary and one multinodular, and were not associated with liver cirrhosis. The carcinoid tumors showed insular, trabecular or glandular arrangement of argyrophilic cells, whereas in the NEC this histological pattern was distorted. Immunohistochemically the tumors showed expression of chromogranin A (all cases), chromogranin B (three cases), pancreastatin and chromostatin (four cases, respectively), prohormone convertase PC3 (three cases), carcinoembryonic antigen (CEA) and CA19‐9 (two cases), cytokeratin 56 kDa (three cases), 160 kDa neurofilament (two cases) and neuron‐specific enolase (two cases). Serotonin and glucagon were sporadically detected in two tumors. The most useful marker to confirm the diagnosis was chromogranin A, which was cleaved to pancreastatin and chromostatin in the tumor tissue, and was more reliable than other markers of neuroendocrine differentiation.

Tuberous sclerosis (TSC) is an autosomal dominant condition characterized by various hamartomas. To assess whether these hamartomas have common features, we immunohistochemically analyzed an autopsy case of TSC with subependymal giant cell astrocytoma, hamartomatous lymphangioleiomyomatosis in the lungs and uterus, and angiomyolipomas in the liver, bilateral kidneys, parametrium, and a lymph node, using the specific antibodies for tuberin (the gene product of TSC2) and HMB-45 (a monoclonal antibody specific for human melanoma). Tuberin was ubiquitously expressed in the normal organs. It was negative or very weakly expressed in the hamartomas. In contrast, HMB-45 was commonly observed in the hamartomas except for the lesions in the brain. The subependymal giant cell astrocytoma was composed of cells immunoreactive for synaptophysin, neurofilament protein, glial fibrillary acidic protein, and S-100 protein but negative for HMB-45 and tuberin. The suppression of tuberin in the brain tumor and visceral hamartomas and an abnormal expression of HMB-45 in the visceral hamartomas were observed. We conclude that the hamartomas associated with TSC have common phenotypic and etiologic expressions and that the genes responsible for both tuberin and the antigen recognized by HMB-45 have important roles in the pathogenesis of these hamartomas.

The immunohistochemical localization of nerve growth factor receptor (NGFR)—high-affinity NGFR (trk A) and low-affinity NGFR (LNGFR)—was investigated in 23 neuroblastoma group tumors, 18 pheochromocytomas, 2 mixed neuroendocrine-neural tumors, and 16 retinoblastomas.trk A was expressed in the tumor cells of all neuroblastomas, pheochromocytomas, and retinoblastomas. Immunoreactive intensity was especially strong in the larger ganglionic tumor cells of ganglioneuroblastoma and ganglioneuroma. Messenger RNA (mRNA) oftrk A was also strongly expressed in the ganglionic cells of ganglioneuroblastomas and chromaffin cells of pheochromocytomas byin situ hybridization method. LNGFR was negative in the tumor cells of neuroblastoma; however, it showed strong immunoreactivity in ganglionic tumor cells and Schwann cells of ganglioneuroblastoma/ganglioneuroma, and sustentacular cells of pheochromocytoma. Although normal retina expressed bothtrk A and LNGFR, tumor cells of retinoblastoma were positive for onlytrk A but negative for LNGFR. Such differences in the expression oftrk A and LNGFR may reflect neuron-glial interactions in the survival and maturation of the sympathetic nerves, retina, and tumors in these tissues.