Investigation of glutathione S-transferase zeta and the development of sporadic breast cancer

Background Certain genes from the glutathione S-transferase superfamily have been associated with several cancer types. It was the objective of this study to determine whether alleles of the glutathione S-transferase zeta 1 (GSTZ1) gene are associated with the development of sporadic breast cancer. Methods DNA samples obtained from a Caucasian population affected by breast cancer and a control population, matched for age and ethnicity, were genotyped for a polymorphism of the GSTZ1 gene. After PCR, alleles were identified by restriction enzyme digestion and results analysed by chi-square and CLUMP analysis. Results Chi-squared analysis gave a χ2 value of 4.77 (three degrees of freedom) with P = 0.19, and CLUMP analysis gave a T1 value of 9.02 with P = 0.45 for genotype frequencies and a T1 value of 4.77 with P = 0.19 for allele frequencies. Conclusion Statistical analysis indicates that there is no association of the GSTZ1 variant and hence the gene does not appear to play a significant role in the development of sporadic breast cancer.

Polymorphisms of glutathione S-transferase genes (GSTM1, GSTP1 and GSTT1) and breast cancer susceptibility

The glutathione S-transferase (GST) family of enzymes function in the body to detoxify carcinogenic compounds. Several genes that code for these enzymes are polymorphic, with particular genotypes previously shown to confer an increased cancer risk. In this study, we investigated the role of three GST genes (GSTM1, GSTP1 and GSTT1) in the development of sporadic breast cancer. Genotypes were determined in 129 breast cancer affected and 129 age and sex matched control individuals. Results did not support an involvement of these specific GST gene polymorphisms, either independently or in combination, in susceptibility to sporadic breast cancer in the tested Australian Caucasian population.

Association of a vitamin D receptor polymorphism with sporadic breast cancer development

Breast cancer is the leading cause of cancer death among Australian women and its incidence is annually increasing. Genetic factors are involved in the complex etiology of breast cancer. The seco-steroid hormone, 1.25 dihydroxy vitamin D3 can influence breast cancer cell growth in vitro. A number of studies have reported correlations between vitamin D receptor (VDR) gene polymorphisms and several diseases including prostate cancer and osteoporosis. In breast cancer, low vitamin D levels in serum are correlated with disease progression and bone metastases, a situation also noted in prostate cancer and suggesting the involvement of the VDR. In our study, 2 restriction fragment length polymorphisms (RFLP) in the 3' region (detected by Apa1 and Taq1) and an initiation codon variant in the 5' end of the VDR gene (detected by Fok1) were tested for association with breast cancer risk in 135 females with sporadic breast cancer and 110 cancer-free female controls. Allele frequencies of the 3' Apa1 polymorphism showed a significant association (p = 0.016; OR = 1.56, 95% CI = 1.09-2.24) while the Taq1 RFLP showed a similar trend (p = 0.053; OR = 1.45, 95% CI = 1.00-2.00). Allele frequencies of the Fok1 polymorphism were not significantly different (p = 0.97; OR = 0.99, 95% CI = 0.69-1.43) in the study population. Our results suggest that specific alleles of the VDR gene located near the 3' region may identify an increased risk for breast cancer and justify further investigation of the role of VDR in breast cancer.

IS-RT-PCR assay detection of MT-MMP in a human breast cancer cell line

The in situ-reverse transcription-polymerase chain reaction (IS-RT-PCR) is a method that allows the direct localisation of gene expression. The method utilises the dual buffer mediated activity of the enzyme rTth DNA polymerase enabling both reverse transcription and DNA amplification. Labelled nucleoside triphosphates allow the site of expression to be labelled, rather than the PCR primers themselves, giving a more accurate localisation of transcript expression and decreased background than standard in situ hybridisation (ISH) assays. The MDA-MB-231 human breast carcinoma (HBC) cell line was assayed via the IS-RT-PCR technique, using primers encoding MT-MMP (membrane-type matrix metalloproteinase) and human β-actin. Our results clearly indicate baseline expression of MT-MMP in the relatively invasive MDA-MB-231 cell line at a signal intensity similar to the housekeeping gene β-actin, and results following induction with Concanavalin A (Con A) are consistent with our previous results obtained via Northern blotting.

A genetic variant located in miR-423 is associated with reduced breast cancer risk

Background/Aim: Since microRNAs (miRNAs) act as translational regulators of multiple genes, single nucleotide polymorphisms (SNP) in them can have potentially wide-ranging effects. Using an association approach, this research examined the effects of the rs6505162 SNP, an A>C polymorphism located in the premiRNA region of miR-423, on breast cancer development. Materials and Methods: Caucasian Australian women with breast cancer and controls matched for age and ethnicity were genotyped for rs6505162 and their genotypic and allelic frequencies analysed for significant differences. Results: Analysis indicated that there were significant differences between the case and control populations (χ 2=6.70, p=0.035), with the CC genotype conferring reduced risk of breast cancer development (odds ratio=0.50 95% confidence interval=0.27-0.92, p=0.03). Conclusion: Further functional research is required to determine the mechanism of action of this SNP on miRNA function.

Expression of glucocorticoid and progesterone nuclear receptor genes in archival breast cancer tissue.

BACKGROUND: Previous studies in our laboratory have shown associations of specific nuclear receptor gene variants with sporadic breast cancer. In order to investigate these findings further, we conducted the present study to determine whether expression levels of the progesterone and glucocorticoid nuclear receptor genes vary in different breast cancer grades. METHODS: RNA was extracted from paraffin-embedded archival breast tumour tissue and converted into cDNA. Sample cDNA underwent PCR using labelled primers to enable quantitation of mRNA expression. Expression data were normalized against the 18S ribosomal gene multiplex and analyzed using analysis of variance. RESULTS: Analysis of variance indicated a variable level of expression of both genes with regard to breast cancer grade (P = 0.00033 for glucocorticoid receptor and P = 0.023 for progesterone receptor). CONCLUSION: Statistical analysis indicated that expression of the progesterone nuclear receptor is elevated in late grade breast cancer tissue.

An androgen receptor mutation in the MDA-MB-453 cell line model of molecular apocrine breast cancer compromises receptor activity

Recent evidence indicates that the estrogen receptor-a-negative, androgen receptor (AR)- positive molecular apocrine subtype of breast cancer is driven by AR signaling. The MDA-MB-453 cell line is the prototypical model of this breast cancer subtype; its proliferation is stimulated by androgens such as 5a-dihydrotestosterone (DHT) but inhibited by the progestin medroxyprogesterone acetate (MPA) via AR-mediated mechanisms. We report here that the AR gene in MDAMB- 453 cells contains a G-T transversion in exon 7, resulting in a receptor variant with a glutamine to histidine substitution at amino acid 865 (Q865H) in the ligand binding domain. Compared with wild-type AR, the Q865H variant exhibited reduced sensitivity to DHT and MPA in transactivation assays in MDA-MB-453 and PC-3 cells but did not respond to non-androgenic ligands or receptor antagonists. Ligand binding, molecular modeling, mammalian two-hybrid and immunoblot assays revealed effects of the Q865H mutation on ligand dissociation, AR intramolecular interactions, and receptor stability. Microarray expression profiling demonstrated that DHT and MPA regulate distinct transcriptional programs in MDA-MB-453 cells. Gene Set Enrichment Analysis revealed that DHT- but not MPA-regulated genes were associated with estrogen-responsive transcriptomes from MCF-7 cells and the Wnt signaling pathway. These findings suggest that the divergent proliferative responses of MDA-MB-453 cells to DHT and MPA result from the different genetic programs elicited by these two ligands through the AR-Q865H variant. This work highlights the necessity to characterize additional models of molecular apocrine breast cancer to determine the precise role of AR signaling in this breast cancer subtype. Endocrine-Related Cancer (2012) 19 599–613

Review: "Breast cancer : can you prevent it?" by A. Lawson, J. Lawson. McGraw-Hill Book (1998)

While reviewing this book, I was not of the target audience. For example, there is a first chapter (presented as a case study, and integrated in an unconvincing manner into the remainder of the book) that obviously meant to soften the book for the lay person. In the third chapter, the authors provide their philosophical interpretation on the meaning of breasts for reasons that entirely escape me, and that have no relation to the book as a whole. Finally, there are potted histories of the heroics of ‘tireless’, ‘dedicated’ and ‘earnest’ epidemiologists, some of whom have nothing to do with breast cancer or the book at all. Despite this lack of focus, the authors give an honest and coherent account of the current state of breast cancer research from an epidemiological viewpoint...

Cross-sectional survey of the health behaviour of southeast Queensland women with cancer-treatment induced menopause : Implications for cancer and primary care nurses

Purpose Women who experience cancer treatment-induced menopause are at risk of long-term chronic morbidity. This risk can be prevented or offset with adherence to health promotion and risk reduction guidelines. The purpose of this study was to explore health behaviours in younger female survivors of cancer and the variables (quality of life and psychological distress) believed to moderate health behaviours. Design Cross-sectional survey of a convenience sample of women (n = 85) in southeast Queensland. Methods Health behaviour and health status were elicited with items from the Australian Health Survey and the Behavioural Risk Factor Surveillance System. The WHO Quality of Life (Brief) measured participants’ self-reported quality of life and their satisfaction with their health. The Brief Symptom Inventory-18 measured psychological distress. Findings Higher self-reported health status was associated with regular exercise and better quality of life. However, a substantial proportion of participants did not engage in the physical activity, dietary or cervical screening practices recommended by Australian guidelines. Conclusions The participants require education regarding the benefits of diet, exercise, weight loss and decreased alcohol intake, as well as information on future health risks and possible comorbidities. These education sessions could be addressed by a nurse-led health promotion model of care at the time of discharge or in the community.

Cardiac safety concerns for ondansetron, an antiemetic commonly used for nausea linked to cancer treatment and following anaesthesia

Introduction: Ondansetron is a 5-HT3 receptor antagonist commonly used as an anti-emetic to prevent the nausea and vomiting associated with anti-cancer drugs, cancer radiotherapy, or postoperatively. Recently, the US Food and Drug Administration (FDA) issued a warning for ondansetron due to a potential for prolongation of the QT interval of the electrocardiogram (ECG), a phenomenon that is associated with an increased risk of the potentially fatal arrhythmia torsade de pointes. Areas covered: We undertook a review of the cardiac safety of ondansetron. Our primary sources of information were PubMed (with downloading of full articles), and the internet. Expert opinion: The dose of ondansetron that the FDA has concerns about is 32 mg iv (or several doses that are equivalent to this), which is only used in preventing nausea and vomiting associated with cancer chemotherapy. This suggests that ondansetron may be safe in the lower doses used to prevent the nausea and vomiting in radiation treatment or postoperatively. However, as there is a report that a lower dose of ondansetron prolonged the QT interval in healthy volunteers, this needs to be clarified by the FDA. More research needs to be undertaken of the relationship between QT prolongation and torsades in order that the FDA can produce clear-cut evidence of pro-arrhythmic risk when introducing warnings for this.

Incidence of unilateral arm lymphoedema after breast cancer : a systematic review and meta-analysis

Background The body of evidence related to breast-cancer-related lymphoedema incidence and risk factors has substantially grown and improved in quality over the past decade. We assessed the incidence of unilateral arm lymphoedema after breast cancer and explored the evidence available for lymphoedema risk factors. Methods We searched Academic Search Elite, Cumulative Index to Nursing and Allied Health, Cochrane Central Register of Controlled Trials (clinical trials), and Medline for research articles that assessed the incidence or prevalence of, or risk factors for, arm lymphoedema after breast cancer, published between January 1, 2000, and June 30, 2012. We extracted incidence data and calculated corresponding exact binomial 95% CIs. We used random effects models to calculate a pooled overall estimate of lymphoedema incidence, with subgroup analyses to assess the effect of different study designs, countries of study origin, diagnostic methods, time since diagnosis, and extent of axillary surgery. We assessed risk factors and collated them into four levels of evidence, depending on consistency of findings and quality and quantity of studies contributing to findings. Findings 72 studies met the inclusion criteria for the assessment of lymphoedema incidence, giving a pooled estimate of 16·6% (95% CI 13·6–20·2). Our estimate was 21·4% (14·9–29·8) when restricted to data from prospective cohort studies (30 studies). The incidence of arm lymphoedema seemed to increase up to 2 years after diagnosis or surgery of breast cancer (24 studies with time since diagnosis or surgery of 12 to <24 months; 18·9%, 14·2–24·7), was highest when assessed by more than one diagnostic method (nine studies; 28·2%, 11·8–53·5), and was about four times higher in women who had an axillary-lymph-node dissection (18 studies; 19·9%, 13·5–28·2) than it was in those who had sentinel-node biopsy (18 studies; 5·6%, 6·1–7·9). 29 studies met the inclusion criteria for the assessment of risk factors. Risk factors that had a strong level of evidence were extensive surgery (ie, axillary-lymph-node dissection, greater number of lymph nodes dissected, mastectomy) and being overweight or obese. Interpretation Our findings suggest that more than one in five women who survive breast cancer will develop arm lymphoedema. A clear need exists for improved understanding of contributing risk factors, as well as of prevention and management strategies to reduce the individual and public health burden of this disabling and distressing disorder.

Delineating breast cancer cell interactions with engineered bone microenvironments

The mechanisms leading to colonization of metastatic breast cancer cells (BCa) in the skeleton are still not fully understood. Here, we demonstrate that mineralized extracellular matrices secreted by primary human osteoblasts (hOBM) modulate cellular processes associated with BCa colonization of bone. A panel of four BCa cell lines of different bone-metastatic potential (T47D, SUM1315, MDA-MB-231, and the bone-seeking subline MDA-MB-231BO) was cultured on hOBM. After 3 days, the metastatic BCa cells had undergone morphological changes on hOBM and were aligned along the hOBM's collagen type I fibrils that were decorated with bone-specific proteins. In contrast, nonmetastatic BCa cells showed a random orientation on hOBM. Atomic force microscopy-based single-cell force spectroscopy revealed that the metastatic cell lines adhered more strongly to hOBM compared with nonmetastatic cells. Function-blocking experiments indicated that β1-integrins mediated cell adhesion to hOBM. In addition, metastatic BCa cells migrated directionally and invaded hOBM, which was accompanied by enhanced MMP-2 and -9 secretion. Furthermore, we observed gene expression changes associated with osteomimickry in BCa cultured on hOBM. As such, osteopontin mRNA levels were significantly increased in SUM1315 and MDA-MB-231BO cells in a β1-integrin-dependent manner after growing for 3 days on hOBM compared with tissue culture plastic. In conclusion, our results show that extracellular matrices derived from human osteoblasts represent a powerful experimental platform to dissect mechanisms underlying critical steps in the development of bone metastases.

The impact of risk-reducing hysterectomy and bilateral salpingo-oophorectomy on survival in patients with a history of breast cancer – a population-based data linkage study

Prophylactic surgery including hysterectomy and bilateral salpingo-oophorectomy (BSO) is recommended in BRCA positive women, while in women from the general population, hysterectomy plus BSO may increase the risk of overall mortality. The effect of hysterectomy plus BSO on women previously diagnosed with breast cancer is unknown. We used data from a population-base data linkage study of all women diagnosed with primary breast cancer in Queensland, Australia between 1997 and 2008 (n=21,067). We fitted flexible parametric breast cancer specific and overall survival models with 95% confidence intervals (also known as Royston-Parmar models) to assess the impact of risk-reducing surgery (removal of uterus, one or both ovaries). We also stratified analyses by age 20-49 and 50-79 years, respectively. Overall, 1,426 women (7%) underwent risk-reducing surgery (13% of premenopausal women and 3% of postmenopausal women). No women who had risk-reducing surgery, compared to 171 who did not have risk-reducing surgery developed a gynaecological cancer. Overall, 3,165 (15%) women died, including 2,195 (10%) from breast cancer. Hysterectomy plus BSO was associated with significantly reduced risk of death overall (adjusted HR = 0.69, 95% CI 0.53-0.89; P =0.005). Risk reduction was greater among premenopausal women, whose risk of death halved (HR, 0.45; 95% CI, 0.25-0.79; P < 0.006). This was largely driven by reduction in breast cancer-specific mortality (HR, 0.43; 95% CI, 0.24-0.79; P < 0.006). This population-based study found that risk-reducing surgery halved the mortality risk for premenopausal breast cancer patients. Replication of our results in independent cohorts, and subsequently randomised trials are needed to confirm these findings.

Genetic polymorphisms in miRNAs targeting the estrogen receptor and their effect on breast cancer risk

Breast cancer is the cancer that most commonly affects women worldwide. This type of cancer is genetically complex, but is strongly linked to steroid hormone signalling systems. Because microRNAs act as translational regulators of multiple genes, including the steroid nuclear receptors, single nucleotide polymorphisms (SNPs) in microRNAs genes can have potentially wide-ranging influences on breast cancer development. Thus, this study was conducted to investigate the relationships between six SNPs (rs6977848, rs199981120, rs185641358, rs113054794, rs66461782, and rs12940701) located in four miRNA genes predicted to target the estrogen receptor (miR-148a, miR-221, miR-186, and miR-152) and breast cancer risk in Caucasian Australian women. By using high resolution melt analysis (HRM) and polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP), 487 samples including 225 controls and 262 cases were genotyped. Analysis of their genotype and allele frequencies indicated that the differences between case and control populations was not significant for rs6977848, rs66461782, and rs12940701 because their p-values are 0.81, 0.93, 0.1 which are all above the threshold value (p=0.05). Our data thus suggests that these SNPs do not affect breast cancer risk in the tested population. In addition, rs199981120, rs185641358, and rs113054794 could not be found in this population, suggesting that these SNPs do not occur in Caucasian Australians.

Racial differences in physical activity among breast cancer survivors : implications for breast cancer care

Background: Physical activity after breast cancer diagnosis is associated with improved survival. This study examines levels of and changes in physical activity following breast cancer diagnosis, overall and by race. Methods: The Carolina Breast Cancer Study, Phase III, assessed pre- and post-diagnosis physical activity levels in a cohort of 1,735 women, aged 20-74, diagnosed with invasive breast cancer between 2008 and 2011 in 44 counties of North Carolina. Logistic regression and analysis of variance were used to examine whether demographic, behavioral and clinical characteristics were associated with activity levels. Results: Only 35% of breast cancer survivors met current physical activity guidelines post-diagnosis. A decrease in activity following diagnosis was reported by 59% of patients, with the average study participant reducing their activity by 230 minutes (95% CI: 190, 270). Following adjustment for potential confounders, when compared to white women, African-American women were less likely to meet national physical activity guidelines post-diagnosis (odds ratio: 1.38, 95% CI: 1.01, 1.88), reported less weekly post-diagnosis physical activity (182 vs. 215 minutes; p=0.13), and reported higher average reductions in pre- versus post-diagnosis weekly activity (262 vs. 230 minutes; p-value = 0.13). Conclusion: Despite compelling evidence demonstrating the benefits of physical activity post-breast cancer, it is clear that more work needs to be done to promote physical activity in breast cancer patients, especially among African-American women.