Biomedical subjects

G Gamberi

Publications and source records attributed to G Gamberi.

24 records · Page 2Linked to original sources

PubMed1997

Altered G1 phase regulation in osteosarcoma.

Alterations in the normal cell cycle lead to abnormal cell proliferation and to tumor development. To explore the role of the cyclin D/Cdk4 complex and the retinoblastoma protein (pRb) in the growth and spread of osteoblastic osteosarcoma (OS), 40 tumor samples were selected. In 17 of these cases, lung metastases occurred during follow-up. Expression of pRb, cyclin D1 and its catalytic subunit, Cdk4, was studied by immunohistochemistry and immunoblotting. As controls, non-neoplastic tissues surrounding the tumor were used. The expression level and pattern were compared to clinical outcome. Cdk4 was over-expressed in 80% of OS, independently of clinical outcome, and showed an intense and uniform distribution in tumor cells compared to normal cells. However, co-immunoprecipitation of Cdk4 with cyclin D1 revealed low levels of cyclin D/Cdk4 complex; 20 of 40 OS examined had a negative or minimal immunostaining for active pRb. The probability of relapse was significantly higher in pRb-negative than in the -positive patients (p < 0.05). The ratio of unphosphorylated/hyperphosphorylated pRb was lower in relapsed patients than in patients with no evident disease, though the difference was not statistically significant. High levels of pRb/cyclin D1 were found in all samples exhibiting functional pRb expression. Our results show that G1 phase deregulation is involved in formation and development of OS. The expression levels of both pRb and cyclin D1 had a clear correlation with clinical outcome, suggesting that these parameters could be used as prognostic markers.

Bone Neoplasms↗

PubMed1994

Cytokeratin expression and distribution in adamantinoma of the long bones and osteofibrous dysplasia of tibia and fibula. An immunohistochemical study correlated to histogenesis.

Twenty-four cases of adamantinoma and 24 cases of osteofibrous dysplasia of the long bones were studied to evaluate the expression and distribution of cytokeratin (CK) subtypes in relation to histogenesis and differentiation. The immunohistochemical study was performed on tissue fixed in buffered formalin and embedded in paraffin wax utilizing antibodies to vimentin, factor VIII, epithelial membrane antigen and cytokeratins of different molecular weights. In all cases the vimentin antibody marked positively in stroma, endothelium and osteoblasts, while factor VIII expression was confined to endothelial cells. In 71% of adamantinomas, vimentin showed strong immunoreactivity in the tumour cells of nests and tubules. CKAE1/AE3 and CK19 were strongly expressed in all morphological patterns of adamantinoma emphasizing their epithelial origin, while the antibodies to CK8 and CK18 showed a high percentage of negative responses. In osteofibrous dysplasia the epithelial-like component was much smaller than in adamantinoma and was present in scattered islands composed of a few cell positive for CKAE1/AE3 and CK19 and negative for other keratins. These results suggest that these two lesions are of a similar histogenesis.

Ameloblastoma↗

PubMedDate not supplied

C-myc and c-fos in human osteosarcoma: prognostic value of mRNA and protein expression.

The c-myc and c-fos proto-oncogenes have several putative functions, including regulation of cell growth. In many neoplasms c-myc overexpression has been linked to poor prognosis. In order to study the role of c-myc and c-fos expression on the tumorigenesis, and the metastatic spread of osteosarcoma, frozen and paraffin-embedded tissue 38 primary osteosarcoma and 10 lung metastases were analyzed. The mRNA analysis was performed by quantitative reverse transcription-polymerase chain reaction and in situ hybridization. The protein expression was studied by Western blot analysis and immunohistochemistry. C-myc and c-fos were found overexpressed in a high percentage of the relapsed tumors and of the metastases, and overexpression of both oncogenes in the same tumor was strongly correlated to the development of metastases (p < 0.05), as 6 of the 7 primary tumors overexpressing both the oncogenes gave metastases. In conclusion, both c-myc and c-fos are involved in the growth and spread of osteosarcoma and a synchronous overexpression of both oncogenes is highly significant for a metastatic potential of a primary tumor.

Adolescent↗

PubMedDate not supplied

Bone hemangioendothelioma: an immunohistochemical study related to histological malignancy and proliferative activity (NORs).

AIMS AND BACKGROUND: Forty-four bone hemangioendotheliomas (HEs) of different histological grades were studied to evaluate the expression and distribution of laminin, type IV collagen, cathepsin G and cathepsin D in cell differentiation and malignancy. RESULTS: In poorly-differentiated HEs the discontinuous distribution of laminin and type IV collagen around angioblastic cords, tubes and cavities revealed an irregular and disorganized basement membrane (BM) architecture corresponding to an increased cell proliferation and secretion of cathepsin D and cathepsin G by tumor cells. CONCLUSIONS: The mean nucleolar organizer region (NOR) area, as a measure of cell proliferation, was significantly higher in grade 4 malignancies than in lower grades, revealing novel prognostic parameters.

Adult↗

PubMedDate not supplied

Increased c-myc oncogene expression in Ewing's sarcoma: correlation with Ki67 proliferation index.

AIMS AND BACKGROUND: Ewing's sarcoma is a highly malignant musculoskeletal tumor composed of small round cells. Although important results have been achieved with surgery associated with chemotherapy, recurrent disease is still a major problem. In order to define new prognostic factors useful for therapeutic decision-making, we conducted a study on 38 Ewing's sarcoma samples in which c-myc oncogene expression and Ki67 proliferation index were correlated with clinical outcome. METHODS AND STUDY DESIGN: Nineteen patients developed metastases during follow-up and 10 of these patients died. C-myc and Ki67 protein expression was evaluated by immunohistochemistry performed on 5 microm formalin-fixed and paraffin-embedded sections, while the c-myc mRNA transcript was localized using in situ hybridization. RESULTS: A statistically positive correlation was found between c-myc protein and Ki67 (P = 0.001) and c-myc mRNA and Ki67 expression (P = 0.047). The 38 patients were divided into two groups using as the cutoff 50% of Ki67-positive cells. The disease-free survival and overall survival estimates were 68% and 90%, respectively, in the group of patients with a percentage of Ki67-positive cells <50%, and 25% and 50%, respectively, in the group with a percentage of Ki67-positive cells > or = 50%. The difference between the survival curves was statistically significant (P <0.05 and P <0.01). Furthermore, relapsed patients had a high and uniform expression of c-myc protein and mRNA compared to disease-free patients. CONCLUSION: These results suggest a possible role of the c-myc oncogene and Ki67 antigen in the malignant progression of Ewing's sarcoma.

Adolescent↗

PubMedDate not supplied

Additional methods of diagnosis in the histopathology of the musculoskeletal system.

In recent years because of their diagnostic importance techniques of immunohistochemistry have been increasingly employed; The use of specific cellular antibodies has allowed for the recognition of tumors of mesenchymal, epithelial, muscular, endothelial, and neuroendocrine origin, and, within these classes, for the revelation of different cellular populations. These techniques together with histochemical and ultramicroscopic studies help define not only the genesis but also the stage of differentiation and the cell function, which are important factors in the prognosis of tumors. These have proven to be particularly useful for the differential diagnosis of highly undifferentiated forms in which cellular morphology differs from that of the tissue of origin.

Bone Neoplasms↗