PubMed · 8415056
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B Friend. Trial after error.. https://pubmed.ncbi.nlm.nih.gov/8415056/
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Hepatocyte growth factor (HGF), also known as scatter factor, is a powerful motogen, mitogen, and morphogen produced by cells of mesodermal origin, acting on epithelial and endothelial cells. Its receptor is the tyrosine kinase encoded by the c-MET protooncogene. We show that the HGF receptor is expressed by human primary osteoclasts, by osteoclast-like cell lines, and by osteoblasts. In both cell lineages, HGF stimulation triggers the receptor kinase activity and autophosphorylation. In osteoclasts, HGF receptor activation is followed by increase in intracellular Ca2+ concentration and by activation of the pp60c-Src kinase. HGF induces changes in osteoclast shape and stimulates chemotactic migration and DNA replication. Osteoblasts respond to HGF by entering the cell cycle, as indicated by stimulation of DNA synthesis. Interestingly, osteoclasts were found to synthesize and secrete biologically active HGF. These data strongly suggest the possibility of an autocrine regulation of the osteoclast by HGF and a paracrine regulation of the osteoblast by the HGF produced by the osteoclast.
Deletions on the short arm of chromosome 9 (9p21 region) have been reported in a number of hematopoietic and solid tumors. These aberrations on 9p have been previously associated with the loss of the interferon gene cluster and the gene for methylthioadenosine phosphorylase (MTAP), localized to the 9p21-22 region. Recently, two putative tumor suppressor gene(s) CDKN2 and MTS2 have been mapped to the 9p21 region, and shown to be deleted in a large number of tumors including leukemias, melanomas, bladder cancers and brain tumors. We have previously reported a similar 9p21 abnormality and deletions of the CDKN2 and MTS2 genes in a myxoid chondrosarcoma cell line and its subclones. In this study we report consistent abnormalities of chromosome 9 in additional chondrosarcomas examined by a detailed cytogenetic and molecular analysis. Seven chondrosarcoma cell lines, one primary chondrosarcoma, and a benign chondroma were examined. Four of the seven tumor cell lines examined showed grossly visible aberrations of chromosome 9. Molecular analysis of these chondrosarcoma cell lines revealed hemizygous deletions of the interferon genes, and the absence of the MTAP gene, protein or activity. In addition, four of the seven chondrosarcoma cell lines also showed deletions of the CDKN2 and/or MTS2 putative tumor suppressor genes, or the absence of the CDKN2 protein product. No such chromosome 9 related aberrations were detected in the benign chondroma. These data suggest that chromosome 9p21 abnormality, and deletions of the CDKN2 and MTS2 tumor suppressor genes may be a significant event in the development of chondrosarcomas.
PURPOSE: Radiotherapy (RT) has been the predominant local treatment for Ewing's sarcoma of bone at the University of Florida. Twice-daily hyperfractionated RT was initiated in 1982 to improve local control and functional outcome. This retrospective review compares the results of once-daily vs. twice-daily RT in patients with primary Ewing's sarcoma of an extremity, with emphasis on functional outcome. METHODS AND MATERIALS: Between June 1971 and January 1990, 37 patients were treated at the University of Florida for nonmetastatic Ewing's sarcoma of bone with a primary lesion in an extremity. Three patients underwent amputation. Of 34 patients treated with RT, 31 had RT alone and 3 had a combination of RT and local excision. Before 1982, 14 patients received once-daily RT; since 1982, 17 patients have received twice-daily RT. Doses of once-daily RT varied from 47 to 61 Gy at 1.8-2 Gy per fraction. Doses of twice-daily RT varied, depending on the response of the soft-tissue component of the tumor to chemotherapy, and ranged from 50.4 to 60 Gy at 1.2 Gy per fraction. Some patients in the twice-daily RT group also received total body irradiation 1-3 months after local RT as part of a conditioning regimen before marrow-ablative therapy with stem cell rescue. They received either 8 Gy in two once-daily fractions or 12 Gy in six twice-daily fractions. The six patients who received surgery were excluded from local control analysis. Local control rates were calculated using the Kaplan-Meier (actuarial) method. Fifteen patients had a formal functional evaluation. RESULTS: In the 31 patients treated with RT alone, the actuarial local control rate at 5 years was 81% for patients treated twice daily and 77% for those treated once daily (p = NS). No posttreatment pathologic fractures occurred in patients treated twice daily, whereas five fractures occurred in those treated once daily (p = 0.01). On functional evaluation, less loss in range of motion (15 degrees vs. 28 degrees of loss, p = 0.02) and a lesser degree of muscle atrophy (8% vs. 21% loss in muscle circumference, p = 0.0004) occurred with twice-daily than with once-daily RT. A trend toward less fibrosis and less local alopecia was seen in patients treated twice daily. Patients treated twice daily received a higher Musculoskeletal Tumor Society functional rating (determined by the Department of Orthopaedics) than those treated once daily (29.4 vs. 26.0, p = 0.15). CONCLUSIONS: Local control rates were similar in the two groups (77% vs. 81%), but functional results were superior in the group treated twice daily.