Biomedical subjects

S Romain

Publications and source records attributed to S Romain.

49 records · Page 3Linked to original sources

PubMed1991

Determination of oestrogen receptors: application of the Passing-Bablock linear regression technique for comparison of enzyme immunoassay and radioligand binding assay in 1841 breast cancer tumours.

To test the qualities of two assays in the same laboratory on the same tumours, a single-point dextran-coated charcoal radioligand binding assay (RLA-DCC) and the Abbott enzyme immunoassay (EIA) were used to perform oestrogen receptor determinations on cytosols from 1841 breast cancers over a 2-year period. Statistical analysis of the data was performed by the Passing-Bablock linear regression technique. The final regression curve between EIA (y) and RLA-DCC (x) yielded y = 1.187 x fmol/mg of protein. However, a high variability in this correlation was observed from 1986 to 1988. This variability could be explained by calibration problems in the immunoassay kits and changes in our technical team. The binding assay appears to be more sensitive to the technicians' experience than the immunoassay. Other technical points are discussed, particularly cytosol preparation and KCl presence or absence in the homogenisation buffer. Finally, the Passing-Bablock and the least squares regression procedures are compared. The conditions allowing optimal correlation and routine determination reliability are defined and the correlation variability is discussed.

Breast Neoplasms↗

PubMed1991

[Determination of estradiol receptors by immunoenzyme technique and by radioligand binding in 2134 breast tumors].

In order to test the qualities of the 2 assays, in the same laboratory and on the same tumors, a single-point dextran-coated charcoal radioligand binding assay (RLA-DCC) and Abbott enzyme immunoassay (EIA) were used for more than two years to perform estrogen receptor determinations on cytosols from 2,134 breast cancers. Statistical analysis of the data was performed according to the method of Passing-Bablock. The final regression curve between EIA (y) and RLA-DCC (x) was excellent y = 1.187 X fmol/mg of protein. However, from 1986 to 1988, a great variability was observed for this correlation. We report the study of this variability, which could be explained by several factors, especially calibration problems for the immunoassay kits and changes in our technical team. The binding assay appears to be more sensitive to the technicians' experience than the immunoassay. Technical points are discussed, particularly cytosol preparation and KCl presence or absence in the homogeneisation buffer. The conditions allowing for optimal correlation and routine determination fiability can therefore be defined.

Breast↗

PubMed1991

[Reevaluation of indications for adjuvant hormone therapy in primary breast cancer with high metastatic risk].

This study concerns the correlation between ER and PR status, menopausal status and the effect of adjuvant hormonotherapy in high risk primary breast cancer patients. We have compared the results obtained in a randomized trial (Institut Paoli-Calmettes, Marseille) with those of a historic series (Centre René Huguenin, Saint-Cloud). The patients presented the same clinical and histological criteria and received identical therapeutic protocols (chemotherapy and/or hormonotherapy). Compared with patients receiving no adjuvant treatment, it appeared that: 1) in post-menopausal patients, a significant detrimental effect of tamoxifen was found in ER-negative patients, while in ER-positive patients hormonal treatment was well correlated with both the presence and level of steroid receptors; 2) in pre-menopausal patients, hormonal therapy (oophorectomy + tamoxifen) appeared to be mediated by a complex mechanism involving more than an ER-positive cell population. In the light of the published results, the present findings underline the importance of reevaluating the indications of hormonotherapy in terms of hormone receptors and menopausal status. They also indicate the importance of biological factors in the evaluation of response to therapy. They can identify, subsets of patients in whom a given therapeutic protocol is detrimental, even though it may be beneficial for the overall population. heterogeneity in response to therapy among patient subsets is one of the most important problems which confronts medical statisticians and clinical investigators.

Adult↗

PubMed1990

[Prognostic value of thymidine kinase in cancer of the breast].

We have measured by a radioenzymatic assay the thymidine kinase in the cytosol of 182 primary infiltrating breast cancers. Maximal follow-up is 95 months. Thymidine kinase was found to be related to SBR grade, tumour size and absence of oestradiol receptors (RE). Univariate analysis has pointed out a significant linkage between overall or metastase free survival and thymidine kinase, using a cut-off level of 80 mU/mg protein which is the most discriminating value. Thymidine kinase appeared to be particularly useful in lymph-node-positive, RE-negative and grade 3 patients. Multivariate analysis of the overall survival and of the metastase free survival (Cox model) revealed that they were strongly related to thymidine kinase status.

Axilla↗

PubMed1990

[Cathepsin D: an independent prognostic factor in cancer of the breast].

The total amount of cathepsin-D (mature forms and pro-enzyme especially) in the cytosol of 88 breast cancers including 85 primary cancers and 11 axillary lymph node metastasis was measured by way of immuno-radiometric assay. Maximum follow-up is 58 months. Cathepsin-D was found to be independent of clinical and biological parameters including axillary lymph node involvement and oestradiol receptors (RE). Univariate analysis has pointed out a significant linkage between overall survival and cathepsin-D, using a cut-off level of 30 pmol/mg protein which is the most discriminating value. Cathepsin-D appeared to be particularly useful in lymph-node-positive and RE-negative patients but it was not significant in the node-negative population. Multivariate analysis of the overall survival (Cox model) revealed that it was strongly related to oestradiol receptor, lymph node involvement and cathepsin-D.

Adult↗

PubMed1989

Prognostic value of epidermal growth factor receptor in node-positive breast cancer.

The prognostic significance of EGFR (epidermal growth factor receptor) was studied in a cohort of 68 node-positive patients with breast cancer, who entered a controlled protocol of adjuvant therapy between February 1980 and June 1984. EGFR radioligand binding assay was carried out on frozen stored samples. Twenty five (37%) of 68 primary sites and 9 (41%) of 19 lymph node metastases assayed were EGFR-positive with a cut off value of 5 fmol/mg membrane protein; there is no statistical difference between the two distributions. EGFR was significantly correlated to ER and histological grade. EGFR-positive tumors and high levels of EGFR were mainly found in the ER-negative group of tumors (p = 0.008) and in histological grade III (p = 0.007). Fifty five patients could be followed for 40 to 92 months. EGFR was an independent prognostic factor for survival after 40 months (p = 0.05). EGFR+/ER- patients had the lowest survival probability, but statistical significance was not reached (p = 0.06). The EGFR phenotype appeared as a patients with different early outcome, with potential therapeutic implication especially in the group of ER-negative patients. These results emphasize the need for a standardized assay methodology and for further clinical studies, particularly in protocols where adjuvant hormonal therapy is prescribed on the basis of steroid hormone receptor status, in order to assess the respective prognostic worth of EGFR and ER (or PR).

Axilla↗

PubMed1989

Correlation of erbB-2 gene amplification with low levels of estrogen and/or progesterone receptors in primary breast cancer: do erbB-2 products delineate hormone-independent tumors?

We analyzed erbB-2 gene amplification in 170 primary breast carcinomas. Thirty-one percent of tumors exhibited additional copies of erbB-2 gene. Chi-square analysis did not elicit any association between gene amplification and either menopausal or node status. A slight trend was observed with respect to the SBR grading. In contrast, significant correlation was associated with the age of patients and we found a strong relation with the intratumoral steroid receptor status. ErbB-2 amplification significantly occurs in tumors whose estrogen receptor and progesterone receptor were below the cut-off value or absent and tumors with dissociated estrogen receptor and progesterone receptor status were revealed as entities similar to both estrogen receptor and progesterone receptor negative tumors.

Adult↗

PubMedDate not supplied

[Results of the conservative surgical and irradiation treatment of 132 nonpalpable ductal carcinomas in situ of the breast].

PURPOSE: Retrospective analysis of results of treatment of 132 subclinical ductal carcinomas in situ, non-palpable. MATERIAL AND METHODS: Patients were treated with limited surgery and 70 Gy radiation therapy (70 Gy). RESULTS: With a median follow-up of 7 years, the total recurrence rate was 6%, and the actuarial rate at 5 years 4% and at 10 years 13% at. These have no influence on recurrence on the specific actuarial survival rate which was 100% at 10 years. In spite of five infiltrating recurrences of seven, no metastasis appeared 48 months after the salvage surgery. The global rate of breast preservation was 92% at 7 years. DISCUSSION AND CONCLUSION: Therapeutic indications were developed taking into account the present analysis and a literature review (2,338 in situ ductal carcinomas, palpable or not, treated with conservative surgery, with or without adjuvant radio-therapy).

Adult↗

PubMedDate not supplied

Mutation analysis in the coding sequence of thymidine kinase 1 in breast and colorectal cancer.

We report the first mutational study of thymidine kinase 1 (TK1) performed in human solid tumors. We sequenced cDNAs representing the complete coding region of TK1 in human breast (n=22) and colorectal (n=26) cancer. Codon 106 near the ATP binding site constantly differed (ATG --> GTG; Met --> Val) from the one deposited by Bradshaw and Deininger in the Genbank database (Accession number NM_003258). Silent polymorphisms at codon 11 (CCC --> CCT; Pro --> Pro) and codon 75 (GCG --> GCA; Ala --> Ala) were frequently detected in tumors as well as in normal tissues. In breast cancer the two polymorphisms were observed in 63.6% of the samples analyzed. No significant association could be found between polymorphisms and TK activity. In colorectal cancer the incidence of the two changes was 73.1% and 69.2%, respectively. Interestingly, one colon cancer with high cytosolic TK activity displayed two missense mutations located in and near the putative phosphorylation site by tyrosine kinase (s) (TAT --> CAT; Tyr --> His) and by cAMP-, cGMP-dependent protein kinase (TAC --> TGC; Tyr --> Cys), respectively; adjacent normal mucosa showed no mutation. This may open new avenues that imply TK1 activity in tumor cell proliferation.

Adenosine Triphosphate↗

PubMedDate not supplied

Reliability and discriminant validity of HER2 gene quantification and chromosome 17 aneusomy analysis by real-time PCR in primary breast cancer.

There is an increasing demand for the evaluation of HER2 status in breast cancer. In this study, sections from fixed tissues and triton extracts of tissue homogenates were obtained from 163 malignant breast tumors and analyzed in parallel using immunohistochemistry combined with fluorescence in situ hybridization, as gold standard tests, and an ELISA test (c-erbB2/c-neu Rapid Format ELISA, Oncogene Research Products, USA). Tumor DNA was employed to evaluate two quantitative PCR methods: the HER2/neu DNA Quantification Kit (Roche Diagnostics GmbH, Germany), which uses the gastrin chromosome 17 reference gene, and our recently developed Oncolab qPCR assay, where both a chromosome 17 gene (somatostatin receptor type II (SSTR2)) and a non-chromosome 17 reference gene (glyceraldehyde-3-phosphate deshydrogenase (GAPDH)) were used to detect an increase in HER2 gene copy number and to evaluate the aneusomy of chromosome 17, respectively. By IHC/FISH and ELISA, HER2 was overexpressed in 27 (16.6%) and 24 (14.7%) samples, respectively. With the Roche and Oncolab qPCR assays, 29 (17.8%) samples showed a ratio of HER2/gastrin > or = 2.0 and 26 (16.0%) showed a ratio of HER2/SSTR2 > or = 2.0, respectively. In samples presenting HER2/SSTR2 <2.0 and HER2/GAPDH > or = 2.0, which was indicative of a chromosome 17 polysomy, we observed a modest increase in HER2 protein expression. Complete agreement between the four methods for HER2 status determination was obtained for 154 (94.5%) samples. Overall, these results demonstrate that quantitative PCR is a reliable method for analyzing HER2 status and chromosome 17 polysomy.

Biomarkers, Tumor↗

PubMedDate not supplied

[Standardization and quality control in the evaluation of proliferation parameters in T1T2, N0N1, M0 breast cancer : multicentric retrospective study I. DNA synthesis enzyme activities].

As part of a clinical research project co-ordinated in Grenoble, six French institutions (CRLCC Angers, CHU Grenoble, Hospices civils Lyon, AP Marseille, CRLCC St-Cloud, CHU Tours) grouped together in order to study the following proliferative parameters in primary breast cancer: DNA synthesis enzymes [thymidine kinase (TK), thymidylate synthase (TS)], signal transduction enzyme [protein tyrosine kinase (PTK)] and S-phase fraction (%S). TK, TS and PTK were measured in cytosols using radio-enzymatic biochemical methods. S-phase was estimated using flow cytometry. The first step consisted in standardization and technical validation of the measurements. The second step consisted in the clinical validation by using a retrospective series of 1,003 breast cancers T1T2, N0N1, M0. We report the results of the first step, together with the distributions of the variables and their relationship with classical clinical variables: 1) Using standardized methods and a cytosolic control, a good reproducibility of measurements was obtained, whether assays were performed in one (TS, PTK) or in several laboratories (TK). 2) Significantly different distributions of TK and TS were observed between the different centres mainly due to different conditions of storage of tumours and cytosols. 3) A highly significant correlation was observed between TK, TS and PTK. Highest TK, TS and PTK levels were observed in tumours with high histological grade or receptor negative tumors. This study clearly illustrates the importance of quality assurance of multicentre studies.

Adult↗

PubMedDate not supplied

[Standardization and quality control in the evaluation of proliferation parameters in T1T2, N0N1, M0 breast cancer: multicentric retrospective study II. DNA-ploidy and S-phase fraction].

As part of a clinical research project, proliferative parameters were studied in primary breast cancer: standardization and technical validation of thymidine kinase (TK), thymidylate synthase (TS) and protein tyrosine kinase (PTK) are described. A total of 633 frozen tumor specimens, available in four institutions, was analyzed in three flow cytometry laboratories for DNA content and percentage of S-phase cells (%S) measurement. 1) The standardization step consisted in developing a common protocol for sample preparation; then, common cell suspensions were analyzed in order to perform an inter-laboratory control. Objective guidelines were elaborated to interpret DNA histograms in breast carcinoma. 2) DNA-aneuploidy was observed in 61% of cases of the retrospective series. Compared with DNA-aneuploid tumors, mean %S was significantly lower in case of DNA-diploidy (respectively: 6.4% and 2.2%, p < 0.001). When compared between the four institutions, %S distributions did not differ significantly. 3) %S is strongly correlated with TK, TS and PTK and high percentages were also observed in high grade tumors or tumor without hormone receptors. These results show that a standardization in using flow cytometers and DNA software allows multicenter studies.

Adult↗

PubMedDate not supplied

EORTC receptor and biomarker study group report analytical and technical evaluation of a thymidine kinase radio-enzymatic assay in breast cancer cytosols.

BACKGROUND: High thymidine kinase (TK) activity in cancer cells could counteract adjuvant chemotherapy directed at the inhibition of de novo DNA synthesis. TK is an independent prognostic factor in breast cancer patients receiving adjuvant chemotherapy. MATERIAL AND METHODS: In this paper, we describe the effects of extraction and dilution buffer composition on TK enzymatic activity values obtained in breast cancer cytosols with the Prolifigen serum TK-REA kit (Sangtec Medical, Sweden). RESULTS: The addition of MgCl2 and ATP early in the assay, preferably during the extraction of tumor tissue, seems critical to stabilise the enzyme. Furthermore, the use of normal calf serum to dilute both standards and samples is necessary to obtain satisfactory parallelism between TK values in serial dilutions of breast cancer cytosols. CONCLUSION: Based on the data reported here, the manufacturer has changed the cytosol diluent composition and is adding a specific cytosol assay insert to the Prolifigen TK-REA kit. As evidenced by the laboratory reproducibility, these modifications to the serum assay led to an adequate, standardized protocol for analyzing TK activity in breast tumor cytosols.

Biomarkers, Tumor↗