Evaluation of applying IHC4 as a prognostic model in the translational study of Intergroup Exemestane Study (IES): PathIES.

BACKGROUND: Intergroup Exemestane Study (IES) was a randomised study that showed a survival benefit of switching adjuvant endocrine therapy after 2-3 years from tamoxifen to exemestane. This PathIES aimed to assess the role of immunohistochemical (IHC)4 score in determining the relative sensitivity to either tamoxifen or sequential treatment with tamoxifen and exemestane. PATIENTS AND METHODS: Primary tumour samples were available for 1274 patients (27% of IES population). Only patients for whom the IHC4 score could be calculated (based on oestrogen receptor, progesterone receptor, HER2 and Ki67) were included in this analysis (N = 430 patients). The clinical score (C) was based on age, grade, tumour size and nodal status. The association of clinicopathological parameters, IHC4(+C) scores and treatment effect with time to distant recurrence-free survival (TTDR) was assessed in univariable and multivariable Cox regression analyses. A modified clinical score (PathIEscore) (N = 350) was also estimated. RESULTS: Our results confirm the prognostic importance of the original IHC4, alone and in conjunction with clinical scores, but no significant difference with treatment effects was observed. The combined IHC4 + Clinical PathIES score was prognostic for TTDR (P < 0.001) with a hazard ratio (HR) of 5.54 (95% CI 1.29-23.70) for a change from 1st quartile (Q1) to Q1-Q3 and HR of 15.54 (95% CI 3.70-65.24) for a change from Q1 to Q4. CONCLUSION: In the PathIES population, the IHC4 score is useful in predicting long-term relapse in patients who remain disease-free after 2-3 years. This is a first trial to suggest the extending use of IHC4+C score for prognostic indication for patients who have switched endocrine therapies at 2-3 years and who remain disease-free after 2-3 years.

Prognostic and predictive importance of the estrogen receptor coactivator AIB1 in a randomized trial comparing adjuvant letrozole and tamoxifen therapy in postmenopausal breast cancer: the Danish cohort of BIG 1-98.

PURPOSE: To evaluate the estrogen receptor coactivator amplified in breast cancer 1 (AIB1) as a prognostic marker, as well as a predictive marker for response to adjuvant tamoxifen and/or aromatase inhibitors, in early estrogen receptor-positive breast cancer. METHOD: AIB1 was analyzed with immunohistochemistry in tissue microarrays of the Danish subcohort (N = 1396) of the International Breast Cancer Study Group's trial BIG 1-98 (randomization between adjuvant tamoxifen versus letrozole versus the sequence of the two drugs). RESULTS: Forty-six percent of the tumors had a high AIB1 expression. In line with previous studies, AIB1 correlated to a more aggressive tumor-phenotype (HER2 amplification and a high malignancy grade). High AIB1 also correlated to higher estrogen receptor expression (80-100 vs. 1-79%), and ductal histological type. High AIB1 expression was associated with a poor disease-free survival (univariable: hazard ratio 1.35, 95% confidence interval 1.12-1.63. Multivariable: hazard ratio 1.29, 95% confidence interval 1.06-1.58) and overall survival (univariable: hazard ratio 1.34, 95% confidence interval 1.07-1.68. Multivariable: hazard ratio 1.25, 95% confidence interval 0.99-1.60). HER2 did not seem to modify the prognostic effect of AIB1. No difference in treatment effect between tamoxifen and letrozole in relation to AIB1 was found. CONCLUSIONS: In a subset of the large international randomized trial BIG 1-98, we confirm AIB1 to be a strong prognostic factor in early breast cancer. Hence, although tumor AIB1 expression does not seem to be useful for the choice of tamoxifen versus an aromatase inhibitor in postmenopausal endocrine-responsive breast cancer, AIB1 is an interesting target for new anti-cancer therapies and further investigations of this biomarker is warranted.

Prognostic and predictive value of ERß1 and ERß2 in the Intergroup Exemestane Study (IES)-first results from PathIES†.

BACKGROUND: Intergroup Exemestane Study (IES) was a randomised study that showed a survival benefit of switching adjuvant endocrine therapy after 2-3 years from tamoxifen to exemestane. PathIES aimed to assess the potential prognostic and predictive value of ERß1 and ERß2 expression in primary tumours in order to determine benefit in the two treatment arms. PATIENTS AND METHODS: Primary tumour samples were available for 1256 patients (27% IES population). ERß1 and ERß2 expression was dichotomised at the median IHC score (high if ERß1 ≥ 191, ERß2 ≥ 164). Hazard ratios (HRs) were estimated by multivariable Cox proportional hazards models adjusting for clinicopathological factors. Treatment effects with biomarker expressions were determined by interaction tests. Analysis explored effects of markers both as a continuous variable and with dichotomised cut-offs. RESULTS: Neither ERß1 nor ERß2 were associated with disease-free survival (DFS) or overall survival (OS) in the whole cohort. In patients treated with continued tamoxifen, high ERß1 expression compared with low was associated with better DFS [HR = 0.38:95% confidence interval (CI) 0.21-0.68, P = 0.001]. DFS benefit of exemestane over tamoxifen (HR = 0.40:95% CI 0.22-0.70) was found in the low ERß1 subgroup (interaction P = 0.01). No significant difference with treatment was observed for ERß2 expression in either DFS or OS. CONCLUSION: In the PathIES population, exemestane appeared to be superior to tamoxifen among patients with low ERß1 expression but not in those with high ERß1 expression. This is the first trial of its kind to report a parameter potentially predicting benefit of an aromatase inhibitor when compared with tamoxifen and an independent validation is warranted.

Prognostic and predictive role of ESR1 status for postmenopausal patients with endocrine-responsive early breast cancer in the Danish cohort of the BIG 1-98 trial.

BACKGROUND: Estrogen Receptor 1 (ESR1) aberrations may be associated with expression of estrogen receptor (ER) or progesterone receptor (PgR), human epidermal growth factor receptor-2 (HER2) or Ki-67 labeling index and prognosis. PATIENTS AND METHODS: ESR1 was assessed in 1129 (81%) of 1396 postmenopausal Danish women with early breast cancer randomly assigned to receive 5 years of letrozole, tamoxifen or a sequence of these agents in the Breast International Group 1-98 trial and who had ER ≥ 1% after central review. RESULTS: By FISH, 13.6% of patients had an ESR1-to-Centromere-6 (CEN-6) ratio ≥ 2 (amplified), and 4.2% had ESR1-to-CEN-6 ratio <0.8 (deleted). Deletion of ESR1 was associated with significantly lower levels of ER (P < 0.0001) and PgR (P = 0.02) and more frequent HER2 amplification. ESR1 deletion or amplification was associated with higher-Ki-67 than ESR1-normal tumors. Overall, there was no evidence of heterogeneity of disease-free survival (DFS) or in treatment effect according to ESR1 status. However, significant differences in DFS were observed for subsets based on a combination of ESR1 and HER2 status (P = 0.02). CONCLUSIONS: ESR1 aberrations were associated with HER2 status, Ki-67 labeling index and ER and PgR levels. When combined with HER2, ESR1 may be prognostic but should not be used for endocrine treatment selection in postmenopausal women with endocrine-responsive early breast cancer.

Which patients benefit most from adjuvant aromatase inhibitors? Results using a composite measure of prognostic risk in the BIG 1-98 randomized trial.

BACKGROUND: On average, aromatase inhibitors are better than tamoxifen when used as initial or sequential therapy for postmenopausal women with endocrine-responsive early breast cancer. Because there may be contraindications to their use based on side-effects or cost, we investigated subgroups in which aromatase inhibitors may be more or less important. PATIENTS AND METHODS: Breast International Group 1-98 trial randomized 6182 women among four groups comparing letrozole and tamoxifen with sequences of each agent; 5177 (84%) had centrally confirmed estrogen receptor (ER) positivity. We assessed whether centrally determined ER, progesterone receptor (PgR), human epidermal growth factor receptor 2, and Ki-67 labeling index, alone or in combination with other prognostic features, predicted the magnitude of letrozole effectiveness compared with either sequence or tamoxifen monotherapy. RESULTS: Individually, none of the markers significantly predicted differential treatment effects. Subpopulation treatment effect pattern plot analysis of a composite measure of prognostic risk revealed three patterns. Estimated 5-year disease-free survival for letrozole monotherapy, letrozole→tamoxifen, tamoxifen→letrozole, and tamoxifen monotherapy were 96%, 94%, 93%, and 94%, respectively, for patients at lowest risk; 90%, 91%, 93%, and 86%, respectively, for patients at intermediate risk; and 80%, 76%, 74%, and 69%, respectively, for patients at highest risk. CONCLUSION: A composite measure of risk informs treatment selection better than individual biomarkers and supports the choice of 5 years of letrozole for patients at highest risk for recurrence.

Supraphysiological hyperinsulinaemia is necessary to stimulate skeletal muscle protein anabolism in older adults: evidence of a true age-related insulin resistance of muscle protein metabolism.

AIMS/HYPOTHESIS: The physiological increase in muscle protein anabolism induced by insulin is blunted in healthy, glucose-tolerant older adults. We hypothesised that the age-related defect in muscle protein anabolism is a true insulin resistance state and can be overridden by supraphysiological hyperinsulinaemia. METHODS: We used dye dilution, stable isotopic and immunoblotting techniques to measure leg blood flow, muscle protein synthesis, protein kinase B/mammalian target of rapamycin (Akt/mTOR) signalling, and amino acid kinetics in 14 healthy, glucose-tolerant older volunteers at baseline, and during an insulin infusion at postprandial (PD, 0.15 mU min(-1) 100 ml(-1)) or supraphysiologically high (HD, 0.30 mU min(-1) 100 ml(-1)) doses. RESULTS: Leg blood flow, muscle protein synthesis, and Akt/mTOR signalling were not different at baseline. During hyperinsulinaemia, leg blood flow (p < 0.01) and muscle protein synthesis increased in the HD group only (PD [%/h]: from 0.063 +/- 0.006 to 0.060 +/- 0.005; HD [%/h]: from 0.061 +/- 0.007 to 0.098 +/- 0.007; p < 0.01). Muscle Akt phosphorylation increased in both groups, but the increase tended to be greater in the HD group (p = 0.07). The level of p70 ribosomal S6 kinase 1 (S6K1) phosphorylation increased in the HD group only (p < 0.05). Net amino acid balance across the leg improved in both groups, but a net anabolic effect was observed only in the HD group (p < 0.05). CONCLUSIONS/INTERPRETATION: We conclude that supraphysiological hyperinsulinaemia is necessary to stimulate muscle protein synthesis and anabolic signalling in healthy older individuals, suggesting the existence of a true age-related insulin resistance of muscle protein metabolism.

Human-human hybridomas and human monoclonal antibodies obtained by fusion of lymph node lymphocytes from breast cancer patients.

Lymphocytes from lymph nodes obtained from breast cancer patients undergoing mastectomy were fused with the 0467.3, UC729HF2, or KR-12 human cell lines, totaling 42 fusions with lymphocytes from 23 patients. A total of 1696 human-human hybridomas were generated, 675 (39.8%) of which produced human IgG and/or IgM. Seventy-three human hybridomas produced antibodies binding to autologous malignant breast tissue and/or MCF-7 cells, as assayed by immunohistology or by cell-binding enzyme-linked immunosorbent assay. Twelve of these hybridomas, all reacting with malignant breast tissue, were subcloned to stabilize the production of human immunoglobulin. The reaction patterns of these 12 human monoclonal antibodies were investigated further by immunohistology on formalin-fixed, paraffin-embedded tissues. The reaction patterns of the various antibodies showed substantial variation and the antibodies reacted with a varying frequency with antigens expressed by different malignant breast tumors. One of these antibodies, MAC 40/43 (IgM), reacted with malignant breast and colon carcinomas and other epithelial derived neoplasms but did not react with normal breast tissue or with other normal and malignant tissues tested, except for a weak reaction with certain normal epithelial tissues. The antigen defined by MAC 40/43 was identified as a Mr approximately equal to 47,000 glycoprotein.

Elastosis in relation to prognosis in primary breast carcinoma.

The content of elastic tissue has been evaluated in 171 primary breast carcinomas. Of the tumors, 35% had no or very little elastic tissue in the malignant areas, 42% presented with medium elastosis, and 22% had gross elastosis. The occurrence of elastin has been related to different prognostic factors. An increasing amount of elastin was found with increasing amounts of estrogen receptor (p = 0.0003), while there was only a slight correlation to the progesterone receptor content. Furthermore, the highly differentiated tumors contained more elastin in their tumor tissue than the poorly differentiated tumors (p = 0.003), and parous women had significantly more elastin than nonparous women (p = 0.02). The presence of elastin was not, however, of any demonstrable prognostic significance.

Prognostic value of steroid hormone receptors: multivariate analysis of systemically untreated patients with node negative primary breast cancer.

The value of estrogen and progesterone receptor (ER and PgR, respectively) determinations in predicting the recurrence-free survival (RFS) has been evaluated in a group of 807 node negative breast cancer patients. All of these patients are enrolled in the Danish Breast Cancer Cooperative Group (DBCG) 77-1a and 82-a protocols for low risk patients, and none of them have received systemic adjuvant therapy. At a median observation time of 50 months and in an evaluation of the total patient population as an entity, ER+ patients had only a marginally significant (P = 0.07) longer RFS than ER- patients while PgR+ patients experienced a significant advantage (P = 0.02). Among patients subgrouped according to menopausal status, both ER and PgR statuses were found to be significant prognostic factors for predicting RFS in the premenopausal women (less than 50 years) but not in peri- or postmenopausal women. Using Cox's multivariate analysis, nuclear pleomorphy was found to be the only significant prognostic variable, while the value of PgR status as a prognostic factor approached significance (P = 0.065). Although knowledge of ER status did not significantly improve distinction between patients with good and poor prognoses in the relatively small subgroup of premenopausal patients (n = 120) when PgR status was known, ER+PgR- patients have a lower risk of recurrence or death than ER-PgR- patients. Using a log-likelihood model, significant and distinct cut-off limits for the definition of receptor positivity were found for premenopausal patients: these were 5 fmol/mg cytosol protein for ER and 10 fmol/mg cytosol protein for PgR. These cut-off levels may reflect the ability of the ligand binding assay method used to discriminate between tissues with and without receptor proteins. Qualitative assessment of receptor status was as valuable as quantitative expression of receptor concentrations in predicting the RFS of the natural course of the disease among node negative premenopausal patients.

Prognostic value of surface antigens in primary human breast carcinomas, detected by monoclonal antibodies.

Three monoclonal antibodies, raised against human milk fat globule membranes, have been applied to 194 primary human breast carcinomas. The detected antigenic sites were found to be heterogeneously distributed. A statistical association with estrogen receptor content and grade of anaplasia was found for two of the antigens, Mam 3a and Mam 3b. The presence of all three antigens was independent of menopausal status, age, primary lymph node metastases, and progesterone receptor status. Life table analysis showed a better survival for patients with tumors positive for Mam 3b. The effect of these variables on recurrence-free survival has been analyzed using a Cox regression model. It is found that the most important prognostic factors are the number of positive lymph nodes, the estrogen receptor content, and the menopausal status of the high-risk patients. The ability of a model based on these factors to predict recurrence is not significantly improved by including any of the three surface antigens.

Association between high concentrations of Mr 52,000 cathepsin D and poor prognosis in primary human breast cancer.

The Mr 52,000 cathepsin D is the precursor of a lysosomal protease secreted in excess by breast cancer cells. This protease can degrade extracellular matrices and proteoglycans and is induced by estrogens in estrogen receptor-positive breast cancer cell lines. In a 4- to 6-yr retrospective cohort study, the concentration of the total cathepsin D (precursor plus intermediate and mature chains) was assayed in cytosols of primary tumors from 242 pre/perimenopausal and 154 postmenopausal breast cancer patients in a solid-phase immunoassay using two specific monoclonal antibodies. Patients were initially divided into groups with low, intermediate, or high concentrations of cathepsin D corresponding to the quartiles of the overall distribution. Using these groupings, the level of Mr 52,000 cathepsin D was not significantly associated with the recognized prognostic factors of age, lymph node involvement, tumor size, and/or grade of anaplasia. A significant association was found between cathepsin D concentrations and estrogen receptor status only among pre/perimenopausal patients. Receptor-positive tumors (greater than or equal to 10 fmol of estrogen receptor/mg of cytosol protein) had a significantly greater proportion of patients with high Mr 52,000 cathepsin D concentrations. Patients with high Mr 52,000 cathepsin D concentrations (greater than 78 pmol/mg for pre/perimenopausal and greater than 24 for postmenopausal patients) have shorter recurrence-free survival (P = 0.06 for pre/peri- and P = 0.039 for postmenopausal patients) and have a trend toward shorter overall survival (P = 0.30 and P = 0.089 for pre/peri- and postmenopausal groups, respectively). In multivariate analysis, Mr 52,000 cathepsin D status was found to be an independent prognostic factor for recurrence-free survival of about the same import as lymph node status for both menopausal groups. This first retrospective study demonstrates that the level of Mr 52,000 cathepsin D in cytosol of primary breast cancer biopsies is an independent prognostic factor in predicting relapses in both pre/peri- and postmenopausal patients.

Prognostic usefulness of estrogen receptor immunocytochemical assays for human breast cancer.

Breast cancers of postmenopausal patients at high risk for recurrence participating in an adjuvant therapy protocol were independently assayed for estrogen receptor by conventional dextran-coated charcoal steroid binding assays and by immunocytochemistry (ER-ICA) to compare the two assays and to assess the prognostic usefulness of ER-ICA. The ER-ICA was based on a monoclonal antibody to the estrogen receptor and was applied to lightly fixed, frozen sections of the cancers. Excellent agreement was found between the two estrogen receptor methods. It was found that a combination of the distribution of ER-ICA stained cells and the overall staining intensity gave a statistically significant correlation with the quantitative estrogen receptor dextran-coated charcoal steroid binding assay value. In addition, the overall appraisal of the lesion as ER-ICA positive or negative as well as the ER-ICA staining intensity and proportion of ER-ICA stained cancer cells related to patient disease-free interval and survival, independent of patient lymph node involvement. This relationship of ER-ICA status to prognosis appeared not to relate only to responses to adjuvant tamoxifen treatment since it also was observed with patients who did not receive the antiestrogen.

Value of epidermal growth factor receptor, HER2, p53, and steroid receptors in predicting the efficacy of tamoxifen in high-risk postmenopausal breast cancer patients.

PURPOSE: Few studies have examined the possible importance of biologic prognostic factors in breast cancer connected with differentiation and growth in predicting response to a specific adjuvant treatment. HER2, epidermal growth factor receptor (EGFR), and p53 have all been suggested as possible markers of tamoxifen resistance. The aim of this study was to investigate interactions between adjuvant treatment with tamoxifen and the content of EGFR, HER2, and p53 in steroid receptor-positive patients. PATIENTS AND METHODS: A total of 1,716 high-risk postmenopausal breast cancer patients were randomly assigned to treatment with tamoxifen (868 women) or to observation (848 women) in a prospective trial (Danish Breast Cancer Cooperative Group's 77c protocol). The content of the steroid receptors and expression of p53, EGFR, and HER2 were determined by immunohistochemical analysis of paraffin-embedded tissue. The length of follow-up was 10 years. The end point for this analysis was disease-free survival. RESULTS: Multivariate analysis demonstrated no increased risk of recurrence after treatment with tamoxifen for HER2-, EGFR-, and p53-positive, high-risk, steroid receptor-positive patients. Patients with steroid receptor-positive tumors and positive immunohistochemical staining for HER2, EGFR or p53 benefited from treatment with tamoxifen for 1 year, although the latter variable contained independent prognostic information by itself. CONCLUSION: With the statistical power of the present randomized study, we did not find support for the hypothesis that HER2/EGFR or p53 status predicts benefit from tamoxifen treatment in estrogen receptor-positive patients with early-stage breast cancer. Thus, neither HER2, EGFR, nor p53 overexpression/accumulation should be used as a contraindication for giving tamoxifen.

A kinase inhibitor screen identifies Mcl-1 and Aurora kinase A as novel treatment targets in antiestrogen-resistant breast cancer cells.

Antiestrogen resistance is a major problem in breast cancer treatment. Therefore, the search for new therapeutic targets and biomarkers for antiestrogen resistance is crucial. In this study, we performed a kinase inhibitor screen on antiestrogen responsive MCF-7 cells and a panel of MCF-7-derived tamoxifen- and fulvestrant-resistant cell lines. Our focus was to identify common and distinct molecular mechanisms involved in tamoxifen- and fulvestrant-resistant cell growth. We identified 18 inhibitors, of which the majority was common for both tamoxifen- and fulvestrant-resistant cell lines. Two compounds, WP1130 and JNJ-7706621, exhibiting prominent preferential growth inhibition of antiestrogen-resistant cell lines, were selected for further studies. WP1130, a deubiquitinase inhibitor, induced caspase-mediated cell death in both tamoxifen- and fulvestrant-resistant cell lines by destabilization of the anti-apoptotic protein Mcl-1. Mcl-1 expression was found upregulated in the antiestrogen-resistant cell lines and depletion of Mcl-1 in resistant cells caused decreased viability. JNJ-7706621, a dual Aurora kinase and cyclin-dependent kinase inhibitor, specifically inhibited growth and caused G2 phase cell cycle arrest of the tamoxifen-resistant cell lines. Knockdown studies showed that Aurora kinase A is essential for growth of the tamoxifen-resistant cells and inhibition of Aurora kinase A resensitized tamoxifen-resistant cells to tamoxifen treatment. Preferential growth inhibition by WP1130 and JNJ-7706621 was also found in T47D-derived tamoxifen-resistant cell lines, pointing at Mcl-1 and Aurora kinase A as potential treatment targets. In addition, tumor samples from 244 estrogen receptor-positive breast cancer patients treated with adjuvant tamoxifen showed that higher expression level of Aurora kinase A was significantly associated with shorter disease-free and overall survival, demonstrating the potential of Aurora kinase A as a biomarker for tamoxifen resistance.

The response of muscle protein anabolism to combined hyperaminoacidemia and glucose-induced hyperinsulinemia is impaired in the elderly.

Muscle mass declines with aging. Amino acids alone stimulate muscle protein synthesis in the elderly. However, mixed nutritional supplementation failed to improve muscle mass. We hypothesized that the failure of nutritional supplements is due to altered responsiveness of muscle protein anabolism to increased amino acid availability associated with endogenous hyperinsulinemia. We measured muscle protein synthesis and breakdown, and amino acid transport in healthy young (30 +/- 3 yr) and elderly (72 +/- 1 yr) volunteers in the basal postabsorptive state and during the administration of an amino acid-glucose mixture, using L-[ring-(2)H(5)]phenylalanine infusion, femoral artery and vein catheterization, and muscle biopsies. Basal muscle amino acid turnover was similar in young and elderly subjects. The mixture increased phenylalanine leg delivery and transport into the muscle in both groups. Phenylalanine net balance increased in both groups (young, -27 +/- 8 to 64 +/- 17; elderly, -16 +/- 4 to 29 +/- 7 nmol/(min.100 mL); P: < 0.0001, basal vs. mixture), but the increase was significantly blunted in the elderly (P: = 0.030 vs. young). Muscle protein synthesis increased in the young, but remained unchanged in the elderly [young, 61 +/- 17 to 133 +/- 30 (P: = 0. 005); elderly, 62 +/- 9 to 70 +/- 14 nmol/(min.100 mL) (P: = NS)]. In both groups, protein breakdown decreased (P: = 0.012) and leg glucose uptake increased (P: = 0.0258) with the mixture. We conclude that the response of muscle protein anabolism to hyperaminoacidemia with endogenous hyperinsulinemia is impaired in healthy elderly due to the unresponsiveness of protein synthesis.

Androstenedione does not stimulate muscle protein anabolism in young healthy men.

Androstenedione is the immediate precursor of testosterone. Androstenedione intake has been speculated to increase plasma testosterone levels and muscle anabolism. Thus, androstenedione supplements have become widely popular in the sport community to improve performance. This study was designed to determine whether 5 days of oral androstenedione (100 mg/day) supplementation increases skeletal muscle anabolism. Six healthy young men were studied before the treatment period and after 5 days of oral androstenedione supplementation. Muscle protein turnover parameters were compared to those of a control group studied twice as well and receiving no treatment. We measured muscle protein kinetics using a three-compartment model involving infusion of L-[ring-2H5]phenylalanine, blood sampling from femoral artery and vein, and muscle biopsies. Plasma testosterone, androstenedione, LH, and estradiol concentrations were determined by RIA. After ingestion of oral androstenedione, plasma testosterone and LH concentrations did not change from basal, whereas plasma androstenedione and estradiol concentrations were significantly increased (P<0.05). Compared to a control group, androstenedione did not affect muscle protein synthesis and breakdown, or phenylalanine net balance across the leg. We conclude that oral androstenedione does not increase plasma testosterone concentrations and has no anabolic effect on muscle protein metabolism in young eugonadal men.

Classical prognostic factors in node-negative breast cancer: the DBCG experience.

Classical prognostic factors were analyzed in patients with low-risk primary breast cancer, defined as absence of tumor-positive axillary lymph nodes, tumor size less than or equal to 5 cm in diameter, and no invasion into skin or deep fascia. The primary surgical treatment was total mastectomy and lower axillary dissection. None of the patients received adjuvant therapy. Between 1977 and 1990, 7315 patients entered the study, and at the time of this analysis (January 1, 1990), the median follow-up time is 5 years. In univariate analyses, the following variables were significantly related to recurrence-free survival: age in premenopausal patients; tumor size; number of negative nodes removed; histological grade; and in premenopausal patients, estrogen receptor and progesterone (PgR) status. In multivariate analyses, age in premenopausal patients was the most important factor, followed by tumor size and histological grade, whereas PgR status in premenopausal patients was just of borderline significance. These variables should be included in multivariate analyses testing the value of more recently introduced prognostic factors.

Fluvoxamine inhibits the CYP2C19-catalyzed bioactivation of chloroguanide.

OBJECTIVE: To investigate the interaction between fluvoxamine and chloroguanide (INN, proguanil) to confirm that fluvoxamine inhibits CYP2C19. METHODS: The study was carried out with a randomized, in vivo, crossover design. Six volunteers were extensive metabolizers of the S-mephenytoin oxidation polymorphism, and six volunteers were poor metabolizers. In period A of the study, each subject took 200 mg chloroguanide orally. In period B, each subject took 100 mg/day fluvoxamine for 8 days and on day 6 ingested 200 mg chloroguanide. In both periods, blood and urine were sampled at regular intervals. Chloroguanide and its two metabolites cycloguanil and 4-chlorphenylbiguanide in plasma and in urine were assayed by means of HPLC. RESULTS: During fluvoxamine use, the median of the total clearance of chloroguanide decreased in a statistically significant way from 1282 ml/min to 782 ml/min among the extensive metabolizers, whereas there was no change among the poor metabolizers. The partial clearance of chloroguanide by means of cydoguanil and 4-chlorphenylbiguanide formation among the extensive metabolizers decreased from 222 ml/min and 97 ml/min before to 33 ml/min and 11 ml/min during fluvoxamine intake, respectively. Among poor metabolizers the corresponding values were 35 ml/min and 7.6 ml/min before and 38 ml/min and 6.9 ml/min during fluvoxamine intake. For each metabolite clearance the change was statistically significant among the extensive metabolizers but not among the poor metabolizers. Both cycloguanil and 4-chlorphenylbiguanide formation clearances were statistically significantly higher among the extensive metabolizers than the poor metabolizers in period A but not in period B (phenocopy). CONCLUSION: Fluvoxamine is an effective inhibitor of CYP2C19.

Imipramine demethylation in vivo: impact of CYP1A2, CYP2C19, and CYP3A4.

OBJECTIVE: To further substantiate the role of CYP1A2 and CYP3A4 for the N-demethylation in vivo. At least three different P450s appear to be responsible for the N-demethylation of imipramine to desipramine in vivo: CYP1A2, CYP2C19, and CYP3A4. The role of CYP2C19 in this regard is well documented, but for the two other P450s the evidence is either indirect or based on in vitro studies. METHODS: Phenotypic tests for imipramine N-demethylation, CYP1A2 (caffeine testing), CYP2C19 (mephenytoin and chloroguanide [proguanil] testing), and CYP3A4 (hydrocortisone and quinidine testing) were carried out in 32 healthy young Danes; all were poor (n = 31) or extremely slow extensive metabolizers (n = 1) of sparteine. RESULTS: By exclusion of the insignificant log-transformed variables, multiple regression analysis for In (desipramine/imipramine) showed that only in (mephenytoin S/R) correlated (p = 0.013; r2 = 0.19). For in (2-hydroxydesipramine/2-hydroxyimipramine) we found that in (mephenytoin S/R) and in (4-chlorophenylbiguanide/chloroguanide) correlated (p = 0.001; r2 = 0.41). CONCLUSION: We did not find in vivo evidence of either CYP1A2 or CYP3A4 activity in the N-demethylation of imipramine. This could be due in part to inadequate CYP1A2 and CYP3A4 in vivo function tests.

Short recurrence-free survival associated with high oestrogen receptor levels in the natural history of postmenopausal, primary breast cancer.

The ability of oestrogen and progesterone receptor (ER and PgR, respectively) status to discriminate recurrence-free survival (RFS) among a cohort of consecutively accrued 952 postmenopausal patients has been studied. None of the cohort members investigated were treated with adjuvant therapy. Using a graduated scale of receptor status [low, intermediate and high receptor levels (< 10 vs. 10-107 vs. > or = 108 fmol/mg cytosol protein, respectively)] instead of the more commonly used dichotomous subdivision (positive vs. negative), ER level significantly discriminated between groups of patients with long vs. short RFS. Contrary to our expectations, patients with highest ER levels have as poor a prognosis as ER-negative patients, while patients with intermediate ER levels have longest RFS. The group of patients with ER levels > or = 108 fmol/mg cytosol protein comprises 47% of the cohort. The independent significance of overexpression of ER as a prognostic factor among this patient group is demonstrated in multivariate analysis where ER level is more significant than either grade of anaplasia or tumour size. PgR status did not significantly predict RFS among these patients. While the highest ER levels predispose for poorer prognosis among postmenopausal patients, it is precisely this group that experiences greatest benefit from adjuvant treatment with tamoxifen. Thus, patients who might otherwise go untreated due to their node-negative status can be readily identified and offered adjuvant treatment.