Growth factors and receptors in juvenile nasopharyngeal angiofibroma and nasal polyps: an immunohistochemical study.

Background: Juvenile nasopharyngeal angiofibroma is a rare nasopharyngeal tumor that occurs exclusively in adolescent boys. It is a histologically benign but locally persistent growth of stromal and vascular tissue. Although male hormones and some growth factors, such as transforming growth factor beta1 (TGF-beta1), insulin-like growth factor II (IGF-II), and, lately, the proto-oncogene beta-catenin, have been implicated in the histogenesis of the tumor, the biologic signaling pathways that drive this peculiar fibrovascular proliferation are still nuclear.

The role of calretinin, inhibin, melan-A, BCL-2, and C-kit in differentiating adrenal cortical and medullary tumors: an immunohistochemical study.

Morphologic distinction between adrenal cortical and medullary tumors can be difficult. Previous studies have shown inhibin, melan-A, and BCL-2 to be useful markers for adrenal cortical tumors. We have recently observed a high level of calretinin expression in normal adrenal cortex but not the medulla and therefore evaluated its diagnostic application for adrenal tumors in comparison with inhibin, melan-A, and BCL-2.

C-kit immunoreactivity in endometrial adenocarcinomas and its clinicopathologic significance.

The proto-oncogene c-kit is a transmembrane-tyrosine-kinase receptor that is structurally related to the platelet-derived growth-factor receptor (PDGFR) and is involved in cell differentiation. C-kit has been found to be expressed in certain solid tumors and may play a role in their tumorigenesis. Recently, a tyrosine-kinase inhibitor specific for the PDGFR family, bcr-abl, and c-kit (STI571) has been reported to have therapeutic effects in tumors expressing the aberrant forms or high quantities of target proteins.

Immunophenotype of desmoplastic small round cell tumors as detected in cases with EWS-WT1 gene fusion product.

Desmoplastic small round cell tumor is a rare tumor typically involving peritoneum. Although the histogenesis of desmoplastic small round cell tumor has yet to be elucidated, immunophenotypical and morphological analysis shows a characteristic divergent phenotype overlapping with other round cell tumors such as Ewing's sarcoma/primitive neuroectodermal tumor, rhabdomyosarcoma, small cell mesothelioma, and carcinoma. Detection of the EWS-WT1 gene fusion is characteristic of desmoplastic small round cell tumor and has been used reliably in tumor diagnosis.