Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alterations of tumour suppressor genes are considered crucial steps in the development of human cancers. Expressions of p53 protein, a product of the tumour suppressor gene altered most commonly in human cancers examined so far, were investigated immunohistochemically in 18 osteosarcomas and 40 other malignant and benign lesions of bone. A monoclonal antibody clone PAb240, which recognizes a common conformational epitope of mutant p53 proteins, stained nuclei of tumour cells in 12 of 18 osteosarcomas (67%). Six tumours (33%) particularly showed positive immunoreactions in more than half of the tumour cells. PAb240 also stained tumour cells in a small number of other malignant bone tumours, such as malignant fibrous histiocytoma, chondrosarcoma, and Ewing's sarcomas. Furthermore, a small number of cells of giant-cell tumours were positively stained. In contrast, PAb240 was completely negative in 21 benign bone tumours and reactive lesions examined. Another monoclonal antibody clone PAb1801, which reacts with both wild- and mutant-type p53 protein, reacted in nuclei of tumour cells of 7 osteosarcomas (39%). Most of those also reacted with PAb240. PAb1801 was expressed much more frequently in other malignant bone tumours and giant-cell tumours. In addition, PAb1801 showed intranuclear positive reactions in tumour cells of a benign chondroblastoma, and reactive cells such as actively proliferating preosteoblasts in a myositis ossificans and osteoclast-like giant cells in a giant-cell tumour. The immunoelectron-microscopic observation that p53 protein was localized in euchromatic areas of nuclei of osteosarcoma cells supported the specificity of immunoreaction for p53 protein, indicating an active role of p53 protein in the regulation of DNA synthesis and transcription. These findings suggest that point mutation of the p53 gene is frequently involved in the development of osteosarcomas. PAb240 may be a useful tool not only in screening point mutations of the p53 gene in osteosarcomas but also in the differential diagnosis between osteosarcomas and reactive bone-forming lesions. Expressions of mutant p53 protein were not correlated with any clinical or pathological factors examined, although the results should be confirmed in studies of a large number of osteosarcomas.
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PMID:Analysis of mutant P53 protein in osteosarcomas and other malignant and benign lesions of bone. 841 91

The expression of alpha smooth muscle actin, muscle specific actin, desmin, h-caldesmon, and calponin was studied immunohistochemically in the following soft tissue and bone tumours and tumour-like lesions: muscle fibromatosis, inflammatory pseudotumours, chondroblastoma, enchondroma, chondrosarcoma, fibrous dysplasia, ossifying myositis, osteoblastoma, convential osteosarcoma, leiomyoma and leiomyosarcoma. Tumours and tumour-like lesions with myofibroblastic cells, osteoblasts and chondroblasts frequently exhibited intensive immunoreactivity for the muscle markers, and therefore, some of them may occasionally be confused with leiomyoma and leiomyosarcoma. Calponin does not help to differentiate various mesenchymal tumours expressing muscle markers, because it also stains intensively myofibroblasts, osteoblasts and chondroblasts. We confirmed that h-caldesmon was expressed intensely in leiomyomas and leiomyosarcomas, and never in the other tumours examined, with the exception of three chondroblastomas. The results have shown that h-caldesmon is a rather specific and sensitive marker for smooth muscle tumours, but it can also stain some actin positive myochondroblasts. It is possible that the positivity of h-caldesmon in some chondroblastomas is due to their complete myogenic transdifferentiation, and so we use the term myochondroblasts and myochondrocytes for designation of such S-100 protein, actin, and h-caldesmon positive cells.
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PMID:[Immunohistochemical differentiation of leiomyocellular tumors and tumors with myogenic differentiation]. 1287 3

Extraskeletal osteosarcoma (EOS) is rare and commonly arises in the retroperitoneum, limbs, head and neck. There is no significant difference between EOS and other malignant tumors in soft tissue. Localized pain and swelling are the common presenting symptoms. Clinical diagnosis of EOS is difficult, imaging techniques may be helpful and careful, and the histopathological analysis is necessary. The common histological variants of EOS include: osteoblastoma, chondroblastoma, and fibroblastoma, and other unusual subtypes were reported occasionally. It should be distinguished with myositis ossificans, malignant mesenchymoma, giant cell tumor and parosteal osteosarcoma. We present an EOS arising in the penis. The primary site and histological category of the tumor were extremely rare. We hope the case will be helpful to the recognition of clinical signs, iconography and histopathology of EOS.
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PMID:Extraskeletal osteosarcoma of penis: a case report. 2335 73