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T-cadherin is a unique receptor of adiponectin, which plays a critical role in various angiogenesis. In the present study, T-cadherin expression in tumor vessels of hepatocellular carcinoma (HCC) and, subsequently, the molecular mechanism, which induced T-cadherin expression in sinusoidal endothelial cells were investigated. Sinusoidal endothelium in nontumorous liver, chronic hepatitis, or liver cirrhosis expressed little or no T-cadherin. By contrast, T-cadherin was found in intratumoral capillary endothelial cells of 34 out of 63 HCC specimens. In positive cases, focal T-cadherin expression was found in well-differentiated HCC, whereas diffuse and intense T-cadherin expression was observed in poorly differentiated HCC specimens. T-cadherin was much expressed in intratumoral capillary endothelial cells in a less differentiated HCC region than that in a well-differentiated region in five specimens, in which various differentiated HCC components were coexistent. In a double-cell chamber assay, fibroblast growth factor-2 appeared to have a critical role to induce T-cadherin in cultured liver sinusoidal endothelial cells. The present finding indicated that T-cadherin was selectively expressed in intratumoral capillary endothelial cells of many HCCs, increasingly expressed as tumor progression, and T-cadherin may have a positive role in angiogenesis of HCC. In addition, cross talk between the signal pathways mediated by fibroblast growth factor-2 and adiponectin was suggested.T-cadherin is a unique receptor of adiponectin, which plays a critical role in various angiogenesis. In the present study, T-cadherin expression in tumor vessels of hepatocellular carcinoma (HCC) and, subsequently, the molecular mechanism, which induced T-cadherin expression in sinusoidal endothelial cells were investigated. Sinusoidal endothelium in nontumorous liver, chronic hepatitis, or liver cirrhosis expressed little or no T-cadherin. By contrast, T-cadherin was found in intratumoral capillary endothelial cells of 34 out of 63 HCC specimens. In positive cases, focal T-cadherin expression was found in well-differentiated HCC, whereas diffuse and intense T-cadherin expression was observed in poorly differentiated HCC specimens. T-cadherin was much expressed in intratumoral capillary endothelial cells in a less differentiated HCC region than that in a well-differentiated region in five specimens, in which various differentiated HCC components were coexistent. In a double-cell chamber assay, fibroblast growth factor-2 appeared to have a critical role to induce T-cadherin in cultured liver sinusoidal endothelial cells. The present finding indicated that T-cadherin was selectively expressed in intratumoral capillary endothelial cells of many HCCs, increasingly expressed as tumor progression, and T-cadherin may have a positive role in angiogenesis of HCC. In addition, cross talk between the signal pathways mediated by fibroblast growth factor-2 and adiponectin was suggested.

Summary Twelve cases of phaeochromocytoma (PCC) and four cases of paraganglioma (PGG) were studied by immunohistochemistry and immunoelectron microscopy in order to demonstrate HLA-DR (Ia)-antigen-positive dendritic cells (IaDCs). Dense infiltration of IaDCs was detected in the majority of PCCs revealing high urinary or serum catecholamine levels, but in aggressively growing PCCs, a familial PCC and all PGGs, few IaDCs were demonstrated. Interestingly, these IaDCs were negative for S-100 protein. Although S-100-protein-positive sustentacular-like cells (SCs), morphologically similar to IaDCs, were also present, these were clearly distinguished from IaDCs by our double immunostaining method. Ultrastructurally, IaDCs had smooth or slightly indented nuclei and contained a moderate amount of endoplasmic reticulum, small mitochondria and vacuoles, extending elongated cytoplasmic processes. These results suggest that determination of the quantity of IaDCs is a highly effective method of assessing the character of PCCs, in particular, their prognosis.

Summary A monoclonal antibody, termed K-20, was generated against an anaplastic thymic carcinoma cell line, Ty-82. Subcapsular thymic epithelial cells of the thymus and blood vessels in various organs were shown to react with the K-20 monoclonal antibody by immunohistochemical staining. Immunofluorescent study revealed that various haematopoietic fresh cells and cell lines did not show any significant reactivity with K-20, except for one Epstein-Barr-virus-carrying lymphoma cell line (SP-50B). Western immunoblotting and affinity purification procedure revealed that K-20 was directed to a protein with a molecular weight of 28 kDa. K-20 is unique in its restrictive reactivity with human subcapsular thymic epithelial cells.

The immunohistochemical localization of the alpha and beta subunits of S-100 protein in 4 cases of the malignant Schwannomas arising from von Recklinghausen's disease was investigated by the indirect immunoperoxidase method. S-100 alpha-positive cells were few in presumably normal peripheral nerves, moderate in numbers in plexiform neurofibromas and numerous in malignant Schwannomas. In contrast, S-100 beta immunoreactivity, abundantly detected in normal peripheral nerves and plexiform neurofibromas, was completely negative in all of 4 cases of malignant Schwannoma. In addition, double immunostaining method for both subunits revealed their simultaneous existence in cells in the normal nerves and neurofibroma. These results suggest that malignant change of Schwann cells convert their subunit composition of S-100 protein from beta to alpha in these malignant cells. Although the mechanisms for the proportional conversion of the subunits are as yet undetermined, the immunoreactivity of S-100 alpha subunit may be a useful marker for Schwannoma in malignancy.

Summary Intraluminal crystalloids (ICr) observed in 19 cases of incidental or invasive human prostatic carcinoma (PCa) and in a case of benign prostatic hyperplasia were examined extensively by immunohistochemistry and electron microscopy. They were brilliantly eosinophilic with haematoxylin and eosin, manifesting needlelike, triangular, rectangular, hexagonal and irregular lump-like in shape. They were strongly positive, dark blue, with phosphotungstic acid -haematoxylin (PTAH) stain in all cases examined. Among the human antibodies tested, epithelial membrane antigen (EMA) gave specifically positive immunostainability with ICr in all cases. Annual ring-like lamellar or concentric structures were detected by electron microscopy. Positive staining of ICr with PTAH and anti-EMA antibody is very useful as a diagnostic marker for PCa in human prostatic tissues.

The distribution of S-100 protein positive dendritic cells (S100-DCs) in cancer nests and the expression of HLA-DR antigen on cancer cells in 90 patients with transitional cell carcinoma of the urinary bladder were studied immunohistochemically. A dense infiltrate of S100-DCs (more than 10 S100-DCs/high power field) was detected in 47 out of 90 cases, while in the remaining tumours the infiltrate was sparse. HLA-DR positive cancer cells (DR-CCs) were detected in 24 cases, including 16 with dense DR-CCs (more than 100 DR-CCs/high power field); no expression was observed in the remaining tumours. In terms of the numbers of S100-DCs infiltrating the following statistically significant differences were observed: tumour grading G1>G3, depth of penetration pT0>pT3; (p<0.05), G2>G3, lymphatic invasion->+ and venous invasion ->+; (p<0.01). A multivariate analysis demonstrated that the most important factor affecting prognosis was distant organ and/or lymph node metastasis (p<0.01) the number of S100DCs, with a hazard ratio (HR) of 0.26 (p<0.01), and the number of DR-CCs with HR of 0.18 (p<0.05); these were statistically significant. S100-DCs and DR-CCs may be regarded as independent prognostic factors of tumour growth and progression.