Biomedical subjects

Thibault Verjat

Publications and source records attributed to Thibault Verjat.

4 recordsLinked to original sources

PubMed2006

Prognostic significance of urokinase plasminogen activator and plasminogen activator inhibitor-1 mRNA expression in lymph node- and hormone receptor-positive breast cancer.

BACKGROUND: One of the most thoroughly studied systems in relation to its prognostic relevance in patients with breast cancer, is the plasminogen activation system that comprises of, among others, the urokinase Plasminogen Activator (uPA) and its main inhibitor, the Plasminogen Activator Inhibitor-1 (PAI-1). In this study, we investigated the prognostic value of uPA and PAI-1 at the mRNA level in lymph node- and hormone receptor-positive breast cancer. METHODS: The study included a retrospective series of 87 patients with hormone-receptor positive and axillary lymph node-positive breast cancer. All patients received radiotherapy, adjuvant anthracycline-based chemotherapy and five years of tamoxifen treatment. The median patient age was 54 and the median follow-up time was 79 months. Distant relapse occurred in 30 patients and 22 patients died from breast cancer during follow-up. We investigated the prognostic value of uPA and PAI-1 at the mRNA level as measured by real-time quantitative RT-PCR. RESULTS: uPA and PAI-1 gene expression was not found to be correlated with any of the established clinical and pathological factors. Metastasis-free Survival (MFS) and Breast Cancer specific Survival (BCS) were significantly shorter in patients expressing high levels of PAI-1 mRNA (p < 0.0001; p < 0.0001; respectively). In Cox multivariate analysis, the level of PAI-1 mRNA appeared to be the strongest prognostic factor for MFS (Hazard Ratio (HR) = 10.12; p = 0.0002) and for BCS (HR = 13.17; p = 0.0003). Furthermore, uPA gene expression was not significantly associated neither with MFS (p = 0.41) nor with BCS (p = 0.19). In a Cox-multivariate regression analysis, uPA expression did not demonstrate significant independent prognostic value. CONCLUSION: These findings indicate that high PAI-1 mRNA expression represents a strong and independent unfavorable prognostic factor for the development of metastases and for breast cancer specific survival in a population of hormone receptor- and lymph node-positive breast cancer patients.

Breast Neoplasms↗

PubMed2006

Correction for chromosome-17 is critical for the determination of true Her-2/neu gene amplification status in breast cancer.

PURPOSE: Trastuzumab is the cornerstone for treatment of women with HER2-overexpressing breast cancer, both in the adjuvant and in the metastatic settings. The accurate assessment of HER2 is, therefore, critical to identifying patients who may benefit from trastuzumab-based therapy. This project aimed to determine the optimal scoring method for fluorescence in situ hybridization (FISH) assay. METHODS: FISH assay was done on 893 samples of breast cancer. Three scoring methods were evaluated: Her2/CEP17> or =2, Her2>4, or Her2>6. Protein and gene expression were evaluated by immunohistochemistry (n = 584) and mRNA/assay/nucleic acid sequence-based amplification (NASBA; n = 90). RESULTS: Samples were divided into five groups based on FISH results: disomic amplified and nonamplified, polysomic amplified, nonamplified, and discordant (10.8% of cases, mostly positive with Her2>4 scoring, but negative with the others). Her2/CEP17> or =2 and Her2>6 scoring methods showed the best association (a) with regard to FISH scoring (kappa = 0.906, P < 10(-6)) and (b) between FISH and immunohistochemistry (3+ as positive; kappa > 0.650, P < 10(-6)) or NASBA (kappa > 0.536, P < 10(-6)). Polysomy had an effect on Her2 copy number (P < 10(-6)), but had no effect on protein and mRNA content. Therefore, within the discordant subgroup, for which additive Her-2 gene copies are due to high polysomy, protein and mRNA levels were similar to those of the nonamplified samples. For this subgroup, the best concordance between FISH/immunohistochemistry/NASBA was observed with the Her2/CEP17 ratio and Her-2>6 scoring (68% and 58% perfect matches, respectively). No perfect matches were observed using the Her2>4 scoring method. CONCLUSION: Correction for chromosome-17 is the method of choice for clinical practice; Her-2>6, but not Her-2>4, could be used as an alternative.

Aneuploidy↗

PubMed2006

NASBA: a novel approach to assess hormonal receptors and ERBB2 status in breast cancer.

In human breast cancer, estrogen receptor-alpha (ERalpha), progesterone receptor (PR) and human epidermal growth factor receptor (ERBB2) status are currently determined using different techniques. We propose to assess the mRNA expression of these three clinically relevant markers using a unique technique, real-time nucleic acid sequence-based amplification (NASBA). Gene expression of hormone receptors was analyzed and compared to the cytosolic functional protein content as determined with a ligand binding assay (LBA), while ERBB2 mRNA expression was compared to quantitative PCR and ELISA. We observed that the three markers are significantly overexpressed at the mRNA level in positive tumors, as measured by DNA- or protein-based techniques. Biostatistical analysis of the receiver operating characteristic (ROC) curve demonstrated high concordance between NASBA and LBA [area under the curve (AUC) for ROC of 0.899] and showed that ERalpha status could be predicted using the molecular assay with a sensitivity of 72.7% and a specificity of 93.5%. Similar results were obtained for PR (AUC ROC 0.938, sensitivity 75.3%, specificity 100%). Moreover, excellent concordance was observed between NASBA, quantitative PCR and ELISA with respect to ERBB2 (AUC ROC 0.92, sensitivity 90%, specificity 89.7%; and AUC ROC 0.98, sensitivity 100%, specificity 91.5%, respectively). These results suggest that NASBA is well suited for assessing ER, PR and ERBB2 status in breast tumor samples. This approach is rapid, highly sensitive and a standardized method that could be complementary to the existing techniques, especially for small tumors.

Adult↗

PubMed2004

Multiparametric duplex real-time nucleic acid sequence-based amplification assay for mRNA profiling.

Nucleic acid sequence-based amplification (NASBA) is a sensitive isothermal transcription-based amplification method. We have developed real-time NASBA assays to detect mRNA coding for the estrogen receptor alpha (ESR1) and the progesterone receptor (PGR) in breast tumors by means of duplex reactions using cyclophilin B (PPIB) as the normalizing gene. Both the ESR1/PPIB and PGR/PPIB duplex NASBA assays are highly sensitive, specific, and reproducible. Quantification is determined using external standard calibration curves and the ratio between the number of target and housekeeping gene mRNA copies. Amplification of the target gene in the duplex NASBA assay was disrupted when this latter was mixed with a large amount of the housekeeping PPIB gene, suggesting that it is preferable for the normalizing gene chosen to have an expression level comparable to the target gene. Sensitivity and robustness of the duplex NASBA assays were assessed in breast cancer cell lines. Such a rapid and easy-to-use multiparametric duplex real-time NASBA assay could also advantageously be set up for other mRNA profiling applications.

Biological Assay↗