MIB-1 Antigen Research Articles

Endocrine-paracrine cell types in the prostate and prostatic adenocarcinoma are postmitotic cells

Neuroendocrine (NE) differentiation frequently occurs in common prostatic malignancies and has potential prognostic and therapeutic implications. In a recent study we were able to provide immunohistochemical evidence that endocrine-paracrine cell types represent an androgen-insensitive cell population in prostate cancer, documented by the consistent lack of the pertinent receptor. In this study we investigated the proliferative activity of endocrine-paracrine cell types in normal, hyperplastic, and neoplastic prostate tissue. Using double-label techniques for the endocrine marker chromogranin A (chr A) and the proliferation-associated MIB-1 antigen, we evaluated the proliferative status of endocrine-paracrine cell types in the prostate and prostatic adenocarcinoma showing marked NE differentiation. In this series of carcinomas and in nonneoplastic tissue the proliferative activities were exclusively restricted to nonendocrine cell populations, whereas endocrine-paracrine cell types characterized by Chr A consistently lack MIB-1 immunoreactivity. This may indicate that prostatic endocrine-paracrine cell types do not participate in the cell cycle during normal, hyperplastic, and neoplastic prostatic growth. Based on the present information, the endocrine phenotype can be considered to be an androgen-insensitive, postmitotic subpopulation in the prostate and prostate cancer.

Pineal parenchymal tumors: cell differentiation and prognosis.

Eleven pineal parenchymal tumors were studied using various antibodies specific to the central nervous system and cell-proliferation-related antigen MIB-1 in order to examine the divergent types of cell differentiation and also evaluate prognosis. Electron microscopy was also performed. All tumors were immunohistochemically positive to chromogranin A and alpha B crystallin, and were also highly positive to retinal S protein. Pineocytoma cells contained microtubules, intermediate filaments, glial bundles, clear-centered vesicles and synaptic apparati. Pineoblastoma cells also had microtubules and neurofilaments, but glial filaments and definite synapses were not identifiable. Pineal parenchymal tumors were considered to be of pinealocyte origin, and there was a continuous spectrum of divergent cell differentiation between pineocytoma and pineoblastoma cells. The MIB-1 labeling index correlated well with histological malignancy, neuronal differentiation evaluated immunohistochemically by both neurofilament protein and synaptophysin, and cases with seeding potentials. Although histopathological features of neuronal development were, until recently, seen as the hallmark of benign prognosis in pineal parenchymal tumors, they are now thought to be only one of the pieces of evidence that may be used for purposes of prognosis.