The value of adjuvant radiotherapy on survival and recurrence in triple-negative breast cancer: A systematic review and meta-analysis of 5507 patients.

BACKGROUND: The value of adjuvant radiotherapy in triple negative breast cancer (TNBC) remains unclear. A systematic review and meta-analysis was conducted in TNBC patients to assess survival and recurrence outcomes associated with radiotherapy following either breast conserving therapy (BCT) or post-mastectomy radiotherapy (PMRT). METHODS: Four electronic databases were searched from January 2000 to November 2015 (PubMed, MEDLINE, EMBASE and Web of Science). Studies investigating overall survival and/or recurrence in TNBC patients according to radiotherapy administration were included. A random effects meta-analysis was conducted using mastectomy only patients as the reference. RESULTS: Twelve studies were included. The pooled hazard ratio (HR) for locoregional recurrence comparing BCT and PMRT to mastectomy only was 0.61 (95% confidence interval [CI] 0.41-0.90) and 0.62 (95% CI 0.44-0.86), respectively. Adjuvant radiotherapy was not significantly associated with distant recurrence. The pooled HR for overall survival comparing BCT and PMRT to mastectomy only was 0.57 (95% CI 0.36-0.88) and HR 1.12 (95% CI 0.75, 1.69). Comparing PMRT to mastectomy only, tests for interaction were not significant for stage (p=0.98) or age at diagnosis (p=0.85). However, overall survival was improved in patients with late-stage disease (T3-4, N2-3) pooled HR 0.53 (95% CI 0.32-0.86), and women <40years, pooled HR 0.30 (95% CI 0.11-0.82). CONCLUSIONS: Adjuvant radiotherapy was associated with a significantly lower risk of locoregional recurrence in TNBC patients, irrespective of the type of surgery. While radiotherapy was not consistently associated with an overall survival gain, benefits may be obtained in women with late-stage disease and younger patients.

Background risk of breast cancer influences the association between alcohol consumption and mammographic density.

BACKGROUND: Alcohol consumption has been suggested to increase risk of breast cancer through a mechanism that also increases mammographic density. Whether the association between alcohol consumption and mammographic density is modified by background breast cancer risk has, however, not been studied. METHODS: We conducted a population-based cross-sectional study of 53 060 Swedish women aged 40-74 years. Alcohol consumption was assessed using a web-based self-administered questionnaire. Mammographic density was measured using the fully-automated volumetric Volpara method. The Tyrer-Cuzick prediction model was used to estimate risk of developing breast cancer in the next 10 years. Linear regression models were used to evaluate the association between alcohol consumption and volumetric mammographic density and the potential influence of Tyrer-Cuzick breast cancer risk. RESULTS: Overall, increasing alcohol consumption was associated with higher absolute dense volume (cm(3)) and per cent dense volume (%). The association between alcohol consumption and absolute dense volume was most pronounced among women with the highest (⩾5%) Tyrer-Cuzick 10-year risk. Among high-risk women, women consuming 5.0-9.9, 10.0-19.9, 20.0-29.9, and 30.0-40.0 g of alcohol per day had 2.6 cm(3) (95% confidence interval (CI), 0.2-4.9), 2.9 cm(3) (95% CI, -0.6 to 6.3), 4.6 cm(3) (95% CI, 1.5-7.7), and 10.8 cm(3) (95% CI, 4.8-17.0) higher absolute dense volume, respectively, as compared with women abstaining from alcohol. A trend of increasing alcohol consumption and higher absolute dense volume was seen in women at low (⩽3%) risk, but not in women at moderate (3.0-4.9%) risk. CONCLUSION: Alcohol consumption may increase breast cancer risk through increasing mammographic density, particularly in women at high background risk of breast cancer.

Diabetes and onset of natural menopause: results from the European Prospective Investigation into Cancer and Nutrition.

STUDY QUESTION: Do women who have diabetes before menopause have their menopause at an earlier age compared with women without diabetes? SUMMARY ANSWER: Although there was no overall association between diabetes and age at menopause, our study suggests that early-onset diabetes may accelerate menopause. WHAT IS KNOWN ALREADY: Today, more women of childbearing age are being diagnosed with diabetes, but little is known about the impact of diabetes on reproductive health. STUDY DESIGN, SIZE, DURATION: We investigated the impact of diabetes on age at natural menopause (ANM) in 258 898 women from the European Prospective Investigation into Cancer and Nutrition (EPIC), enrolled between 1992 and 2000. PARTICIPANTS/MATERIALS, SETTING, METHODS: Determinant and outcome information was obtained through questionnaires. Time-dependent Cox regression analyses were used to estimate the associations of diabetes and age at diabetes diagnosis with ANM, stratified by center and adjusted for age, smoking, reproductive and diabetes risk factors and with age from birth to menopause or censoring as the underlying time scale. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, no association between diabetes and ANM was found (hazard ratio (HR) = 0.94; 95% confidence interval (CI) 0.89-1.01). However, women with diabetes before the age of 20 years had an earlier menopause (10-20 years: HR = 1.43; 95% CI 1.02-2.01, <10 years: HR = 1.59; 95% CI 1.03-2.43) compared with non-diabetic women, whereas women with diabetes at age 50 years and older had a later menopause (HR = 0.81; 95% CI 0.70-0.95). None of the other age groups were associated with ANM. LIMITATIONS, REASONS FOR CAUTION: Strengths of the study include the large sample size and the broad set of potential confounders measured. However, results may have been underestimated due to survival bias. We cannot be sure about the sequence of the events in women with a late age at diabetes, as both events then occur in a short period. We could not distinguish between type 1 and type 2 diabetes. WIDER IMPLICATIONS OF THE FINDINGS: Based on the literature, an accelerating effect of early-onset diabetes on ANM might be plausible. A delaying effect of late-onset diabetes on ANM has not been reported before, and is not in agreement with recent studies suggesting the opposite association. STUDY FUNDING/COMPETING INTERESTS: The coordination of EPIC is financially supported by the European Commission (DG-SANCO) and the International Agency for Research on Cancer. The national cohorts are supported by Danish Cancer Society (Denmark); Ligue Contre le Cancer, Institut Gustave Roussy, Mutuelle Générale de l'Education Nationale, Institut National de la Santé et de la Recherche Médicale (INSERM) (France); German Cancer Aid, German Cancer Research Center (DKFZ) and Federal Ministry of Education and Research (BMMF) (Germany); Ministry of Health and Social Solidarity, Stavros Niarchos Foundation and Hellenic Health Foundation (Greece); Italian Association for Research on Cancer (AIRC) and National Research Council (Italy); Dutch Ministry of Public Health, Welfare and Sports (VWS), Netherlands Cancer Registry (NKR), LK Research Funds, Dutch Prevention Funds, Dutch ZON (Zorg Onderzoek Nederland), World Cancer Research Fund (WCRF), Statistics Netherlands (The Netherlands); ERC-2009-AdG 232997 and Nordforsk, Nordic Centre of Excellence programme on Food, Nutrition and Health (Norway); Health Research Fund (FIS), Regional Governments of Andalucía, Asturias, Basque Country, Murcia (no. 6236) and Navarra, ISCIII RETIC (RD06/0020) (Spain); Swedish Cancer Society, Swedish Scientific Council and Regional Government of Skåne and Västerbotten (Sweden); Cancer Research UK, Medical Research Council, Stroke Association, British Heart Foundation, Department of Health, Food Standards Agency, and Wellcome Trust (UK). None of the authors reported a conflict of interest.

Testosterone, SHBG and cardiovascular health in postmenopausal women.

Cardiovascular disease (CVD) affects men and women differently with women having a lower incidence and later onset of disease. Research has recently refocused interest on the cardiovascular role of androgens. The purpose of this review is to summarize the evidence available on the association between testosterone and cardiovascular health in postmenopausal women. Published studies relating testosterone and sex hormone-binding globulin (SHBG) to CVD and its risk factors were reviewed. Studies included in this review suggest that increased androgenicity, characterized by high testosterone and low SHBG levels, is associated with an adverse CVD risk factor profile in postmenopausal women. However, evidence for an association with cardiovascular events is lacking and it is uncertain whether the observed associations with endogenous testosterone have clinical implications regarding the use of postmenopausal testosterone therapy. Large-scale, longitudinal studies relating testosterone and SHBG levels to cardiovascular risk factors and endpoints are needed to determine the temporal relationship between androgenicity and cardiovascular risk and to ascertain the long-term efficacy and safety of testosterone therapy in postmenopausal women.

Effect of transforming growth factor-beta on DNA synthesis by growth plate chondrocytes: modulation by factors present in serum.

Chondrocytes in the growth plate undergo rapid proliferation during the process of enchondral ossification. The factors that regulate this proliferative activity have not been defined although several local autocrine or paracrine growth factors have recently been discovered in cartilage. Transforming growth factor-beta 1 (TGF-beta) is an important regulator of cell metabolism and growth and is present in cartilage. The present study was designed to examine the influence of TGF-beta on DNA synthesis in chick epiphyseal chondrocytes. Chondrocytes were plated in serum-free (BSA-supplemented) medium or medium containing 10% FBS, and after 24 hours in monolayer culture, were treated with TGF-beta in identical medium. A 24 hour incubation with TGF-beta caused a biphasic dose-dependent increase in thymidine incorporation. The effect was greatly increased in serum-containing cultures where a maximal 20-fold increase in thymidine incorporation occurred compared with the 2 1/2-fold maximal increase obtained in serum-free cultures. The effect was present by 12 hours and maximal between 0.3 and 1.0 ng/ml of TGF-beta. Higher concentrations of TGF-beta were less stimulatory. The serum enhancement was dependent upon the simultaneous presence of TGF-beta and serum factors and was abolished when chondrocytes were plated and exposed to TGF-beta in medium containing dialyzed FBS (12-14 kD MW membrane). The nature of the uptake and incorporation of thymidine into DNA by individual chondrocytes appeared to be the same in both TGF-beta-treated and control cultures as the apparent Kms were similar. The present study indicates that TGF-beta increases DNA synthesis by growth plate chondrocytes. The effect is enhanced by factors present in serum.

Effects of transforming growth factor-beta on matrix synthesis by chick growth plate chondrocytes.

Transforming growth factor-beta (TGF beta) is a local regulator of cell metabolism and growth. TGF beta increases the synthesis of collagen and enhances the deposition of matrix by almost all cells studied to date. The presence of TGF beta in cartilage suggests an important autocrine function, and the present study was designed to examine its influence on the matrix synthesis of chick epiphyseal chondrocytes. Chondrocytes were plated in serum-free (BSA-supplemented) medium or medium containing 10% fetal bovine serum (FBS), and after 24 h in monolayer culture were treated with TGF beta in identical medium. A 24-h incubation with TGF beta caused a dose-dependent decrease in collagen synthesis (-14%) and increase in noncollagen protein synthesis (+25%), with greater effects in serum-containing medium (-22% and +58%, respectively). Similarly, the stimulation of sulfate incorporation by TGF beta was greater in FBS-containing medium (+140%) than in serum-free medium (+70%). These changes were present by 6 h, were maximal in the 0.3-3.0 ng/ml dose range, and were found to reflect an alteration in extracellular protein synthesis. The enhancement of TGF beta effects by serum was abolished when chondrocytes were plated and exposed to TGF beta in medium containing dialyzed FBS (12-14K membrane). The present study indicates that TGF beta influences the synthesis of matrix components by growth plate chondrocytes. The effects are enhanced by factors present in serum.

Synthesis of 1,25-dihydroxycholecalciferol and 24,25-dihydroxycholecalciferol by calvarial cells. Characterization of the enzyme systems.

The synthesis of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] and 24,25-dihydroxycholecalciferol [24,25(OH)2D3] from 25-hydroxycholecalciferol [25(OH)D3] has previously been shown to occur in cells isolated from bone. The main findings of the present study are that the enzyme systems which catalyse these syntheses are: (1) active at 'in vitro' substrate concentrations over the range of 2-50 nM; (2) regulatable in a complex way by 1,25(OH)2D3, 24,25(OH)2D3, 25,26-dihydroxycholecalciferol and 25(OH)D3, but not by cholecalciferol ('vitamin D3'); and (3) have relatively short half-lives (approx. 5 h).

Isolation and characterization of bone cells from a patient with osteogenesis imperfecta type 1b.

The metabolic defect(s) in bone cells which manifests itself in the disease osteogenesis imperfecta (OI) type 1 is not known. Since this form of the disease displays both a variable tissue involvement and the possibility of remission it is difficult to attribute its expression to a primary mutation in the structural gene for type I collagen (as can the perinatal lethal forms of OI). In an attempt to more fully understand OI type 1 we have isolated and characterized a subpopulation of cells obtained from a sample of bone from a patient with OI type 1b. This subpopulation of cells has been shown to morphologically resemble the osteoblast phenotype, to contain the highest level of alkaline phosphatase of the cells isolated, to synthesize collagen, to respond to bone target hormones such as 1,25(OH)2D3 and parathyroid hormone, and to proliferate rapidly. Moreover, the response of these cells to the vitamin D metabolites, from the standpoint of growth regulation, is qualitatively different from normal bone cells. We intend to use these cells as a model system for studying the defect in OI type 1b.

The effect of bone cell stimulatory factors can be measured with thymidine incorporation only under specific conditions.

This study examines the efficacy of using radiolabeled thymidine as a measure of bone cell DNA synthesis. The effect of a bone-active peptide on cell proliferation is assessed under different labeling conditions and it is shown that the apparent stimulation in DNA synthesis is due to an increase in participating cells and not to labeling artifacts. In another series of experiments we demonstrate how the use of carrier-free thymidine can cause erroneous results. From these data it is shown that only 10-28% of the cells in culture are participating in DNA synthesis. Therefore, under specific conditions, a 100% stimulation in thymidine incorporation by a mitogenic factor can be caused by as little as a 10% increase in the number of DNA synthesizing cells.

In vitro use of vitamin D3 metabolites: culture conditions determine cell uptake.

This report demonstrates that routine variations in cell culture conditions dramatically affect the amount of vitamin D3 metabolites to which cultured cells have access. Increasing the concentration of a metabolite in the medium increases the amount of the metabolite in the cell compartment. Increasing the volume of medium in the culture dishes (while maintaining a constant metabolite concentration) also increases the amount of metabolite in the cell compartment. Moreover, daily changes of the medium containing fresh metabolite increase the amount of the metabolite in the cell compartment as well. These variables may explain the inability of different laboratories to duplicate dose-response curves.

Bone cell phosphotyrosine phosphatase: characterization and regulation by calcitropic hormones.

Isolated bone cells in culture contain an enzyme capable of hydrolyzing the phosphate ester of phosphotyrosine. This enzyme, which we have termed phosphotyrosine phosphatase, has not previously been reported in bone. Some of its characteristics include: 1) maximum activity near physiological pH, 2) a Km for substrate of 52 microM, 3) marked inhibition by the phosphate analog vanadate ion, 4) activity correlation with bone cell alkaline phosphatase, and 5) regulation by bone target hormones. Data obtained with vanadate ion support the contention that this enzyme may play a role in the regulation of bone cell growth.

Enzymatic isolation of cells from neonatal calvaria using two purified enzymes from Clostridium histolyticum.

The enzymatic isolation of cells with bacterial collagenase has proved to be a powerful technique for the study of a wide variety of tissues. Unfortunately, for some applications such as the isolation of cells from membranous bone, the cellular damage that results from the exposure of the cells to cytotoxic contaminants of bacterial collagenase has limited the usefulness of this approach. The use of chromatographically purified collagenase alone is often ineffective or very slow to release cells from tissue. We have found that two enzymes are necessary and sufficient to isolate cells from neonatal mouse calvaria: purified collagenase and neutral protease. These two enzymes can be chromatographically purified on a preparative scale to yield 100 mg amounts of each enzyme. The purified enzymes can be recombined in amounts which will digest calvaria at the same rate as the crude bacterial collagenase from which they were derived. The cells that are isolated using the purified enzymes are undamaged, as indicated by the measurement of their equilibrium density on gradients of Ficoll and sodium metrizoate. Cells isolated with crude collagenase never reach an equilibrium density upon isopyknic centrifugation, whereas cells isolated with the purified enzymes reach an equilibrium density of 1.074 g/ml in 90 min.

Enzymatic isolation of cells from bone: cytotoxic enzymes of bacterial collagenase.

The enzymatic isolation of cells from fetal rat calvaria is most effectively achieved with crude Clostridium histolyticum collagenase. However, this bacterial collagenase damages the cells during the digestion of the tissue. We have used cell density, as measured by isopycnic centrifugation on polysucrose gradients, as an indicator of cell damage. There are at least two enzymes in crude bacterial collagenase capable of damaging the cells in this tissue. One of these is clostripain that has been well characterized. The other cytotoxic enzyme is uncharacterized, and its effects are not evident until the clostripain activity has been inhibited by alpha-tosyl-lysyl chloromethane. The apparent activity of this second enzyme can be inhibited by withholding magnesium from the digestion medium and by increasing the potassium concentration of the digestion medium.

Application of light sensitive chemicals to probe protein structure and function.

These results suggest that important information regarding the conformation of complementary binding sites and the behavior of various charged states of inhibitors can be obtained from studies of the pH dependence of photoaffinity labeling experiments. This information may assist in identifying the pKas of key residues controlling the binding interaction. This technique should prove very useful in probing binding site structure on nonfunctioning targets, such as enzyme zymogens, as well as complicated receptor interactions.

Fine structure of fetal rat calvarium; provisional identification of preosteoclasts.

This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive dna relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.

Potassium, sodium, and the intracellular fluid space of cells from bone.

Cells enzymatically dispersed from fetal rat calvaria were analyzed for sodium and potassium content and intracellular fluid space (ICF). Even when obtained in comparatively high yield, the cells are damaged by the isolation procedure as evidenced by high sodium and low potassium content immediately after isolation. During a post-incubation period potassium is accumulated and sodium extruded to steady-state levels. Although electrolyte content of cells after recovery did not vary as a function of cell yield, ICF was increased in cells obtained in lower yield, suggesting cell swelling as a result of membrane damage. The weighted mean values obtained for the best cell preparations were 117 mM K+ and 27 mM Na+. Based on DNA assay of isolated cells and the whole tissue, 20- to 21-day calvaria were found to have an average of 8.1 x 10(6) cells/calvarium. Combining cell data with analysis of total tissue sodium, potassium, and water, it was concluded that the tissue extracellular sodium is in equilibrium with blood but that the potassium concentraiton is approximately 5-fold higher than blood levels.

Parathyroid hormone stimulation of collagenase secretion by isolated bone cells.

Cells isolated from fetal rat calvaria were cultured in a [14C]glycine-labeled collagen gel. This method of culture places the cells in an environment similar to that in the intact tissue and provides a means for assaying the release of collagenase from the cells. Degradation of the collagen matrix begins within the first 3 h of cell culture, the earliest time point at which samples were taken, and continues for at least 12 h. When cells were prepared from calvaria incubated for 30 min with parathyroid hormone (PTH), there was a marked decrease in the collagenase content of the freshly isolated cells, indicating that secretion of collagenase had been enhanced by PTH. Upon subsequent culture of control and PTH-pretreated cells, there was an increase in lysis of collagen gels surrounding the hormone-treated cells within 8 h. The increased collagenolysis was prevented by exposure of the cells to puromycin before and during culture, suggesting that collagenase synthesis also was stimulated by PTH.