Romain S

Bio: Romain S is an academic researcher from Curie Institute. The author has contributed to research in topics: Etoposide & Fluorouracil. The author has an hindex of 1, co-authored 2 publications receiving 81 citations.

Thymidine Kinase as a Proliferative Marker: Clinical Relevance in 1,692 Primary Breast Cancer Patients

Abstract: PURPOSE: To assess the prognostic value of thymidine kinase (TK), an enzyme involved in the DNA synthesis salvage pathway, relative to other prognostic factors in primary breast cancer. PATIENTS AND METHODS: This retrospective study involved 1,692 patients with operable breast cancer treated in six institutions (median follow-up, 82 months). Among the 857 node-negative patients, 135 received adjuvant chemotherapy (fluorouracil, doxorubicin, cyclophosphamide [FAC] or fluorouracil, etoposide, and cisplatin [FEC]). TK was assayed in cytosol with a quantitative radioenzymatic technique. Disease-specific survival (DSS), local recurrence-free interval (LRI), and distant-relapse-free interval (DRI) were investigated. RESULTS: High TK levels were associated with large tumor size, high histologic grade, and steroid hormone receptor negativity. Univariate analysis of the entire data set showed that high TK levels were related to shorter DSS (P < 10-5), LRI (P < 10-3), and DRI (P < 10-5). In time-dependent Cox model...

A multicolor nanoprobe for detection and imaging of tumor-related mRNAs in living cells.

Abstract: Cancer is a leading cause of death worldwide and accounts for several millions of deaths every year. The survival of cancer patients is strongly associated with the stage of the tumor at the time of diagnosis. Identifying the cancer at the cellular level in an early stage before metastasis holds great promise for increasing the survival of cancer patients. A major focus of research towards this goal is on the estimation of abnormalities in gene expression in living cells. Tumor-related mRNA has been widely used as a specific marker to assess the migration of tumor cells locally or in the bloodstream. Changes in the level of tumor-related mRNA expression are correlated with tumor burden and malignant progression. The detection of tumor-related mRNA markers in intact cancer cells provides new tools for identifying cancer cells in clinical samples. Recently, a variety of techniques have been exploited to monitor tumor-related mRNAs. Among these methods, fluorescence imaging analysis offers an appealing approach for the detection of cancer at the cellular level, which may be of prognostic significance. Many fluorescence probes have been synthesized for the detection and imaging of mRNA in cancer cells and most of the research focuses on detecting a single type of mRNA, which may yield false positive results and limits the development of intracellular mRNA imaging and detection. Notably, cancer is associated with multiple tumor-related mRNAs, and some mRNA markers are expressed in normal cells. Simultaneous detection of multiple targets brings new opportunities for improving the accuracy of early cancer detection over the single-marker assay. Although various types of platforms for the detection of multiple targets have been developed, none have been designed for imaging three or more markers in living cells. Such intracellular imaging techniques for multiple tumorrelated mRNAs could promote the progress of early cancer detection. Herein, we describe a multicolor fluorescence nanoprobe based on nanoflares, which simultaneously detects three intracellular tumor-related mRNAs. The nanoprobe consists of gold nanoparticles (Au NPs) functionalized with a dense shell of recognition sequences (synthetic oligonucleotides) hybridized to three short dye-terminated reporter sequences by gold–thiol bond formation (Figure 1). The recognition sequences contain 21-base recognition elements for three specific mRNA transcripts: c-myc mRNA, TK1 mRNA, and GalNAc-T mRNA.

FRET Nanoflares for Intracellular mRNA Detection: Avoiding False Positive Signals and Minimizing Effects of System Fluctuations

Abstract: A new class of intracellular nanoprobe, termed fluorescence resonance energy transfer (FRET) nanoflares, was developed to sense mRNA in living cells. It consists of a gold nanoparticle (AuNP), recognition sequences, and flares. Briefly, the AuNP functionalized with recognition sequences hybridized to flares, which are designed as hairpin structures and fluorescently labeled donors and acceptors at two ends, respectively. In the absence of targets, the flares are captured by binding with the recognition sequences, separating of the donor and acceptor, and inducing low FRET efficiency. However, in the presence of targets, the flares are gradually displaced from the recognition sequences by the targets, subsequently forming hairpin structures that bring the donor and acceptor into close proximity and result in high FRET efficiency. Compared to the conventional single-dye nanoflares, the upgraded FRET nanoflares can avoid false positive signals by chemical interferences (such as nuclease and GSH) and thermodynamic fluctuations. Moreover, the signal generation in FRET nanoflares can be easily made with ratiometric measurement, minimizing the effect of system fluctuations.

Correlation between MIB-1 and other proliferation markers: clinical implications of the MIB-1 cutoff value.

Abstract: BACKGROUND Cell proliferation is a major determinant of the biologic behavior of breast carcinoma. MIB-1 monoclonal antibody is a promising tool for determining cell proliferation on routine histologic material. The objectives of this study were to compare MIB-1 evaluation to other methods of measuring cell proliferation, with a view to refining the cutoff used to classify tumors with low and high proliferation rates in therapeutic trials. METHODS One hundred eighty-five invasive breast carcinomas were evaluated for cell proliferation by determining monoclonal antibody MIB-1 staining, histologic parameters (Scarff–Bloom–Richardson grade and mitotic index) on paraffin sections, S-phase fraction (SPF) by flow cytometry, and thymidine-kinase (TK) content of frozen samples. RESULTS There was a high correlation (P = 0.0001) between the percentage of MIB-1 positive tumor cells and SPF, TK, histologic grade, and the mitotic index. Multivariate analyses including MIB-1 at 5 different cutoffs (10%, 15%, 17% [median], 20%, 25%) and the other proliferative markers showed that the optimal MIB-1 cutoff was 25% and that the mitotic index was the proliferative variable that best discriminated between low and high MIB-1 samples. A MIB-1 cutoff of 25% adequately identified highly proliferative tumors. Conversely, with a MIB-1 cutoff of 10%, few tumors with low proliferation were misclassified. CONCLUSIONS The choice of MIB-1 cutoff depends on the following clinical objective: if MIB-1 is used to exclude patients with slowly proliferating tumors from chemotherapeutic protocols, a cutoff of 10% will help to avoid overtreatment. In contrast, if MIB-1 is used to identify patients sensitive to chemotherapy protocols, it is preferable to set the cutoff at 25%. The MIB-1 index should be combined with some other routinely used proliferative markers, such as the mitotic index. Cancer 2002;94:2151–9. © 2002 American Cancer Society. DOI 10.1002/cncr.10458