A comparative study of P53/MDM2 genes alterations and P53/MDM2 proteins immunoreactivity in soft-tissue sarcomas.

In the present study, the expression of P53 and MDM2 proteins were examined in 94 soft-tissue sarcomas (35 malignant fibrohistiocytomas, 15 neurosarcomas, 14 liposarcomas, 13 leiomyosarcomas, 11 fibrosarcomas and 6 dermatofibrosarcomas) by immunohistochemistry. The immunohistochemical findings were correlated with P53 mutation analysis using PCR-SSCP, PCR-HDF and direct sequencing, and MDM2 amplification studies by differential PCR. P53 immunopositivity was found in 25 out of 94 (26.6%) cases. Alterations of the P53 gene were detected in 12 (12.8%) tumors; eight of these tumors revealed P53 immunoreactivity. A high number of P53 positive and P53 mutated tumors were histologically defined as poorly differentiated G3 (64.0% and 75.0%, respectively). MDM2 immunopositivity was revealed in 36 out of 94 (38.3%) cases. MDM2 amplification occurred in 17 tumors (18.1%); only nine of these tumors exhibited MDM2 immunoreactivity. Overall, MDM2 positivity was not associated with MDM2 amplification in 27 out of 94 tumors (28.7%). There was no significant correlation between MDM2 overexpression and histological grade. However, when the samples were stratified by immunophenotype, the majority of tumors (52.5%) with isolated MDM2 overexpression (dissociated from P53 positivity) were defined histologically as low grade (G1 + G2). These results support the notion that besides P53 alterations, MDM2 gene deregulation seems to be an important event in sarcomas evolution. Additionally, the mechanism of MDM2-mediated degradation of P53 protein, without involving stabilization and inactivation of P53 gene, should be considered for better understanding of all features of tumor progression processes.

Expression of P53, MDM2 and Ki-67 antigens in soft tissue sarcomas.

The expression of P53 and MDM2 proteins was examined by immunohistochemistry in 115 soft-tissue sarcomas (STSs), including 32 malignant peripheral nerve sheath tumours, 27 liposarcomas, 18 leiomyosarcomas, 16 synovial sarcomas, 14 fibrosarcomas and 8 dermatofibrosarcomas, to investigate their possible association with clinicopathologic features and proliferative rate. Positivity for P53 and MDM2 was found in 9.7% and 28.1% tumours, respectively. The fraction of P53 and MDM2 positive tumours was the highest in leiomyosarcomas (16.7% and 17.2%, respectively) and the lowest in dermatofibrosarcomas (0% and 4.3%, respectively). Overall, P53(-)/MDM2(+) phenotype predominated (20.2%), while 7.9% of tumours were both P53 and MDM2 positive, and 1.8% of tumours were only P53 positive. P53 accumulation was associated with a high histological malignancy grade and a higher proliferative rate. MDM2 immunoreactivity was revealed in tumours of all malignancy grades and there was no association between MDM2 positivity and tumours proliferative activity. These results suggest that P53 overexpression underlays rather late events in the oncogenesis of STSs, which might be a determinant of their proliferative rate. In contrast, MDM2 deregulation seems to be an early rather than a late event in STSs, which may occur without involving stabilization and inactivation of P53 gene.

Immunohistochemical status of p53, mdm2 and Ki-67 in malignant fibrous histiocytoma.

The aim of the study was to evaluate the frequency of p53, mdm2 and Ki-67 immunopositivity in MFH, and to investigate possible associations of their expression with the grade of malignancy and predominant histological pattern--storiform, pleomorphic and myxoid subtype of MFH. A total number of 51 tumor samples from 21 primary and 30 secondary MFHs was studied using monoclonal anti-p53 (DO-78, DAKO), anti-mdm2 (1F2, NOVOCASTRA) and polyclonal anti-Ki-67 (DAKO) antibodies. The p53 immunopositivity was observed in 32.7% of all tumor samples (in 36.8% of primary and in 30% of recurrent and metastatic tumors). The mdm2 immunopositivity was noted in 34.8% of all tumor samples (in 33.3% of primary and 35.7% of secondary tumors). The mean percentage of p53, mdm2 and Ki-67 positive cells was 15.5, 8.8 and 7.05, respectively. The mean Ki-67 LI was statistically higher in grade 3 than in grade 2 of malignancy (p = 0.006). A significant correlation was found between mdm2 positivity and histological subtypes of MFH--storiform and pleomorphic types were more frequently mdm2 positive than myxoid variant (p = 0.035 and p = 0.009, respectively). No such correlation was observed for p53 positivity of tumors and subtypes, but there was a statistically significant difference in the percentage of p53 positive cells between storiform and myxoid type (p = 0.049). We also noted more tumors expressing high percentage (over 20%) of mdm2 positive cells in pleomorphic and storiform subtypes than in myxoid variant (p = 0.048). The Ki-67 LI was also higher in pleomorphic than in other types of MFH (p = 0.012). A strong positive correlation was found between p53 positivity and mdm2 positivity of tumors in primary MFHs (p = 0.00146). p53 and mdm2 positive tumors were mainly in grade 3 of malignancy, but no statistically significant correlations were noted. A positive correlation between the percentage of p53 positive cells and Ki-67 positive cells (p = 0.0028) was observed.

The expression of the proliferating antigen Ki67, PCNA and products of suppressor gene p53 in primary invasive ductal breast carcinoma.

The classification of histological malignancy by Bloom and Richardson used in ductal invasive breast cancer seems to be not sufficient. In the same group of patients with the same clinical status as well as pathological malignancy the prognosis can be different and unpredictable. The aim of the study was to examine a consecutive series of primary ductal invasive tumours to find out: a) the expression of some biological cellular parameters as proliferating antigens Ki67 and PCNA and the products of the suppressor gene p53; b) the correlation between the levels of expression of those factors and classical prognostic factors, such as tumour diameter, status of axillary lymph nodes, status of steroids receptors, degree of histological differentiation. It seems that the estimation of proliferating antigens together with products of suppressor gene p53 might have greater prognostic value than the estimation of single factors.

A 65 kDa oncofetal protein (p65), proliferating cell nuclear antigen (PCNA) and Ki67 expression in breast cancer patients.

Paraffin-embedded tissue slides from 89 infiltrating ductal breast carcinoma, 10 fibrocystic disease and 10 fibroadenoma were assessed immunohistochemically using monoclonal antibodies against human p65 antigen and polyclonal antibodies against p65-like protein present in fetal bovine serum. We did not find any evident differences in p65 detection by polyclonal and monoclonal antibodies, however, monoclonal antibody seems to be more specific. This factor is not induced by cellular proliferation associated with nonneoplastic diseases what was confirmed by immunohistochemical analysis of expression of p65 protein and well know markers of proliferation (proliferating cell nuclear antigen--PCNA and Ki67). It was established that there is no correlation between p65 and PCNA or Ki67 expression. High proliferating indexes (PI) for PCNA (PI-PCNA) or Ki67 (PI-Ki67) may help in selection of tumors with high proliferating activity independently from histological grade of malignancy established by routine methods. The estimation of p65 protein may be useful in the selection of precancerous changes and more differentiated ductal cancer of the breast what raises the possibility that p65 antigen may be helpful in the screening examination of women with high risk for cancer development.

Glutathione and glutathione metabolizing enzymes in tissues and blood of breast cancer patients.

Many reports indicate that glutathione and enzymes cooperating with it are important in neoplastic processes. Glutathione (GSH) concentrations and glutathione S-transferase (GSH STr) and glutathione peroxidase (GSH-Px) activities were determined in breast cancer tissue and adjacent healthy tissues, as well as in blood of 28 patients. There were considerable differences in the investigated parameters among individual patients. Therefore we analyzed the paired samples of normal and cancerous tissues from the same individual. In 68% of the patients the activities of GSH-Px and in 85% patients those of GSH STr were found to be higher in the tumor than in the normal tissue. GSH concentration in 48% tumor samples were higher and in 44% lower than in corresponding normal tissues. Statistically significant correlation was found between GSH-Px and GSH STr in normal (r = 0.51, p < 0.005) and in cancer tissues (r = 0.64, p = 0.001). Correlation coefficient between GSH Px activity in normal and corresponding cancer tissues was r = 0.71 (p < 0.001), however this correlation in the case of GSH STr was much lower but still significant (r = 0.38, p < 0.05). No significant correlation in the determined parameters was found between erythrocytes or plasma and normal or cancer tissues.

Usefulness of cytogenetic analysis in the diagnosis of undifferentiated synovial sarcoma of the chest wall. A case report.

A case of poorly differentiated spindle cell malignant neoplasm of the chest wall in a 21-year-old man is reported. The results of histopathological and immunohistochemical examinations were not characteristic enough to establish the precise diagnosis. Due to the age of the patient and the location of the lesion and NSE positivity of tumor cells, the possibility of Askin's tumour or malignant peripheral nerve sheath tumour was considered. Cytogenetic analysis revealed a chromosomal translocation t(X;18)(p11;q11), which is known as the specific aberration in synovial sarcoma. Chromosome study seems to be a useful tool for identifying undifferentiated mesenchymal tumours.