Biomedical subjects

I Bodrogi

Publications and source records attributed to I Bodrogi.

60 records · Page 4Linked to original sources

PubMedDate not supplied

MRP expression of testicular cancers and its clinical relevance.

BACKGROUND: The expression of a multidrug resistance associated protein (MRP) has been investigated in a variety of human tumors. However, there is a lack of data regarding its expression in germ cell testicular tumors (GCTTs). PATIENTS AND METHODS: MRP expression was examined by immunohistochemistry (IHC) using mouse monoclonal antibody (MRPm6) against human MRP in 56 testis cancer specimens. This antigen was also correlated with the histology, metastatic behavior, clinical stage and tumor suppressor protein p53 immunostaining of GCTTs. RESULTS: All testis tumors, regardless of their histology, metastatic status and clinical stage gave positive signals. MRP was positive not only in the cytoplasm but, very interestingly, in the nuclei. CONCLUSION: Our results suggested that ala GCTTs express high levels of MRP protein with no relation to any of clinicopathological variables investigated here. Since germ cell tumors are very sensitive to chemotherapy, the role of MRP as mediator of drug resistance seems unconvincing in this malignancy. MRP is located in the cytoplasm and the nuclei of tumor cells and may be involved in transportation and/or redistribution certain substrates from the nucleus to the cytoplasm.

ATP-Binding Cassette Transporters↗

PubMedDate not supplied

Glutathione related enzymes in human testicular germ cell tumors and normal testes.

In this study, the activity of the glutathione related enzymes, namely glutathione S-transferase (GST), glutathione reductase (GSSG-R), Selenium-dependent and -independent glutathione peroxidase (GPX) of various TGC tumors (n = 18) obtained from untreated patients, was compared to that of the corresponding enzymes of normal testicular tissues (n = 5). The enzymes of all tumorous tissues except teratomas were significantly less active, than the corresponding enzymes of nontumorous tissues. The GST was in seminomas 4.3-20-, in embryonal carcinomas 47-, and in mixed tumors 13-47-fold less active than in the normal testes. The GST activity of teratomas was about half of that of the normal tissues. The Se-independent GPX, component of GST alfa class, comprised about 90 percent of the total GPX activity in normal testis; however it was absent or barely detectable in all TGC tumors except teratomas. The latter had about the same GPX activity as the tumor-free testicular tissues. Apart from the teratoma, the GSSG-R activity of all TGC tumors was also suppressed to about one third of that of the normal testis. The insufficient function of glutathione related enzymes of TGC tumors may contribute to their sensitivity against treatment. The poorer prognosis of teratomas, however, may be explained by the relatively higher activity of their detoxifying enzymes.

Germinoma↗

PubMedDate not supplied

Multidrug resistance of testis cancers: the study of clinical relevance of P-glycoprotein expression.

Germ cell testicular tumors (GCTTs) are very sensitive to anticancer treatment. However some patients ultimately die of their disease due to tumor resistance. Multidrug resistance is mediated by the mdr1 gene product P-glycoprotein (P-gp) which is one important mechanism of drug resistance. This study attempted to examine the correlation between P-gp and tumor progression and to evaluate the clinical relevance of P-gp immunoreactivity in patients with GCTT. Expression of the P-glycoprotein was screened in 48 primary human GCTTs, that have not been treated with chemotherapy, using monoclonal antibody (C219) and immunoenzyme staining. Of the samples from 14 seminomatous germ cell testicular tumors (SGCT, 2 seminomas (14%), and of 34 non-seminomatous tumors (NSGCT) 18 (53%) showed high expression of P-glycoprotein. This difference proved to be significant (P = 0.006). The expression of P-gp showed a statistically significant positive correlation with cancers of advanced stages (P = 0.003) and cancers that showed resistance to chemotherapy (P = 0.0052). Detection of P-gp expression in patients with GCTTs before the application of anti-cancer treatment can be used as a useful prognostic marker to isolate patient subgroups with worse prognosis and less susceptibility to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Is p53 expression, detected by immunohistochemistry, an important parameter of response to treatment in testis cancer?

BACKGROUND: Several prior studies revealed positive p53 expression via immunohistochemistry (IHC) in a large percentage of germ cell testicular cancers (GCTTs). However, the predicting and prognostic value of this protein remains to be defined. Therefore, the aim of our study was to further clarify the role of p53 protein in GCTTs and to look for correlations between its gene expression and other disease parameters, including histological subtype, stage and clinical resistance sensitivity. Furthermore, we correlated p53 protein expression with that of MDRI gene product protein (Pgp) in order to examine the interrelationship between these two markers. PATIENTS AND METHODS: 77 untreated patients with GCTTs were investigated for their p53 expression using monoclonal antibody and immunohistochemistry in paraffin-embedded specimens. There were 34 patients with stage I, 16 with stage II, 27 with stage III disease. RESULTS: All tumor types, except differentiated teratomas, were immunoreactive for p53 to a various extent ranging from scarcely positive to homogeneously stained tumor cells. Seminomas (S) and embryonal carcinoma (EC) components showed the most positive nuclear staining. p53 expression showed a significant inverse correlation with the stage of disease (P < 0.0003). There was a significant positive relationship between p53 immunoreactivity and response to treatment (P = 0.0012), i.e. high levels of p53 expression correlated with clinical sensitivity of the tumors to chemotherapy. We could demonstrate a statistically significant opposite relationship between p53 and Pgp immunoreactivity (P < 0.0005). CONCLUSION: Our results show that p53 status in tumor cells may be a strong determinate of susceptibility to chemotherapy and that p53 overexpression has a favorable prognosis in terms of response to treatment in GCTTs. Moreover, the findings provide clinical evidence for the presense of significant relationship between p53 and MDR1/Pgp immunoreactivity. They also suggest that patients resistant to chemotherapy and lacking p53 expression might benefit from an alternative appropriately designed chemotherapeutic regimen to achieve further successful treatment in GCTTs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Differential expression of glutathione S-transferases in germ cell tumors of human testes.

Glutathione S-transferase (GST) isoenzymes alfa, mu and pi were assessed by Western blotting in normal testes, seminomas and non-seminomatous germ cell tumors (NSGCTs). GST alfa and mu were strongly expressed in all normal specimens (n = 6), the pi isoform, however, could not or barely be detected. Ten (92%) of 11 seminomas had GST pi and only 2 (16%) showed alfa expression. In contrast, twelve (80%) of 15 NSGCTs showed a significant level of GST alfa and only 2 (13%) had GST pi expression. The absence or paucity of mu isoform was characteristic for all neoplastic testicular tissues. A statistically significant relationship (P = 0.021) could be established between GST alfa and stages of disease, i.e., alfa isoform was prevalent in the later stage (IIB, III) NSGCT tumors. These results suggest that the poor prognosis of the later stage NSGCTs may be due to their high GST alfa content, while the GST pi does not seem to have role in this relation.

Germinoma↗

PubMedDate not supplied

Drug resistance and sensitivity of germ cell testicular tumors: evaluation of clinical relevance of MDR1/Pgp, p53, and metallothionein (MT) proteins.

BACKGROUND: Although in vitro and clinical studies indicate that overexpression of P-glycoprotein (Pgp), p53, or metallothionein (MT) is involved in modulating drug resistance/sensitivity of cancer cells, the clinical relevance of the overexpression remains to be elucidated. MATERIALS AND METHODS: In this paper the expression and clinical value of Pgp, p53, and MT were evaluated immunohistochemically in 77 specimens of germ cell testicular tumors (GCT). We also studied the interrelationship(s) between the investigated markers. RESULTS: Pgp positivity correlated with cancers of advanced stages (P = 0.000). p53 and MT immunostaining does not predict a poor response to chemotherapy, but rather is correlated to a favorable clinical outcome (P = 0.001, P = 0.00006 respectively). We obtained an inverse association between Pgp and p53 (P = 0.0005), and positive strong association between p53 and MT immunoreactivity (P = 0.0002). CONCLUSIONS: Based on our results in patients with germ cell testicular tumors we assume that the poor clinical outcome seen in certain Pgp positive tumors is the consequence of Pgp association with a more progressive malignant phenotype, rather than its role in multidrug resistance (MDR). p53 and MT immunoreactivity predicts a better response rate to chemotherapy, wheres tumors lacking or demonstrating low MT and or p53 expression show a worse prognosis.

ATP Binding Cassette Transporter, Subfamily B, Mem↗