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.

Detection of mRNA for nuclear receptor co-activators 1 and 3 in archival breast cancer tissue and surrounding stroma : a tissue expression study

Before the age of 75 years, approximately 10% of women will be diagnosed with breast cancer, one of the most common malignancies and a leading cause of death among women. The objective of this study was to determine if expression of the nuclear receptor coactivators 1 and 3 (NCoA1 and NCoA3) varied in breast cancer grades. RNA was extracted from 25 breast tumours and transcribed into cDNA which underwent semi-quantitative polymerase chain reaction, normalised using 18S. Analysis indicated that an expression change for NCoA1 in cancer grades and estrogen receptor alpha negative tissue (P= 0.028 and 0.001 respectively). NCoA1 expression increased in grade 3 and estrogen receptor alpha negative tumours, compared to controls. NCoA3 showed a similar, but not significant, trend in grade and a non-significant decrease in estrogen receptor alpha negative tissues. Expression of NCoA1 in late stage and estrogen receptor alpha negative breast tumours may have implications to breast cancer treatment, particularly in the area of manipulation of hormone signalling systems in advanced tumours.

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.

Diurnal rhythm and effects of feeding, exercise and recombinant equine growth hormone on serum insulin concentrations in the horse

Reasons for performing the study As growth hormone increases lean body mass, it could be a therapy for obese horses. However, growth hormone use induces hyperinsulinaemia in some species, so further investigation is warranted. Objectives To investigate the effects of feeding, exercise and growth hormone therapy on basal insulin concentrations in healthy horses. Study design In vivo experimental study. Methods Blood samples were obtained every 30 min from 12 geldings over 24 h, to establish basal serum insulin concentrations, before they underwent a 3-week exercise programme. Horses were allocated into 2 groups and exercised for another 4 weeks. Group A received daily i.m. injections of recombinant equine growth hormone; 5 mg/day for 5 days, then 12.5 mg/day for 16 days. Blood samples were taken daily before feeding. Insulin vs. time area under curve of Groups A and B were compared using a Student's unpaired t test. Results Horses demonstrated insulin peaks within 2 h of feeding of 577 ± 108.3 pmol/l at 09.30 h and 342.4 ± 75.7 pmol/l at 17.30 h, despite receiving the same meal. The nadir was between midnight and 07.30 h. Exercise had no effect on basal insulin concentrations prior to equine growth hormone administrations. The equine growth hormone injections increased serum insulin concentrations (P = 0.01) within Group A, from 44.4 ± 15.3 pmol/l initially to 320.9 ± 238.2 pmol/l by Day 12. Exogenous growth hormone caused variable hyperinsulinaemia, which was alleviated once equine growth hormone administration ceased. Conclusions Single serum samples taken prior to the morning meal provide basal insulin concentrations. Exercise did not change basal insulin concentrations. However, equine growth hormone injections increased basal insulin concentrations, which were not ameliorated by exercise. Potential relevance This therapy is not recommended to address obesity in insulin-resistant equids.

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

Separable and non-separable discrete wavelet transform based texture features and image classification of breast thermograms

Highly sensitive infrared cameras can produce high-resolution diagnostic images of the temperature and vascular changes of breasts. Wavelet transform based features are suitable in extracting the texture difference information of these images due to their scale-space decomposition. The objective of this study is to investigate the potential of extracted features in differentiating between breast lesions by comparing the two corresponding pectoral regions of two breast thermograms. The pectoral regions of breastsare important because near 50% of all breast cancer is located in this region. In this study, the pectoral region of the left breast is selected. Then the corresponding pectoral region of the right breast is identified. Texture features based on the first and the second sets of statistics are extracted from wavelet decomposed images of the pectoral regions of two breast thermograms. Principal component analysis is used to reduce dimension and an Adaboost classifier to evaluate classification performance. A number of different wavelet features are compared and it is shown that complex non-separable 2D discrete wavelet transform features perform better than their real separable counterparts.

Gene expression profiling in human breast cancer – toward personalised therapeutics?

The most integrated approach toward understanding the multiple molecular events and mechanisms by which cancer may develop is the application of gene expression profiling using microarray technologies. As molecular alterations in breast cancer are complex and involve cross-talk between multiple cellular signalling pathways, microarray technology provides a means of capturing and comparing the expression patterns of the entire genome across multiple samples in a high throughput manner. Since the development of microarray technologies, together with the advances in RNA extraction methodologies, gene expression studies have revolutionised the means by which genes suitable as targets for drug development and individualised cancer treatment can be identified. As of the mid-1990s, expression microarrays have been extensively applied to the study of cancer and no cancer type has seen as much genomic attention as breast cancer. The most abundant area of breast cancer genomics has been the clarification and interpretation of gene expression patterns that unite both biological and clinical aspects of tumours. It is hoped that one day molecular profiling will transform diagnosis and therapeutic selection in human breast cancer toward more individualised regimes. Here, we review a number of prominent microarray profiling studies focussed on human breast cancer and examine their strengths, their limitations, clinical implications including prognostic relevance and gene signature significance along with potential improvements for the next generation of microarray studies.

The role of fathers in child feeding : perceived responsibility and predictors of participation

Background The role of fathers in shaping their child’s eating behaviour and weight status through their involvement in child feeding has rarely been studied. This study aims to describe the fathers’ perceived responsibility for child feeding, and to identify predictors of how frequently fathers eat meals with their child. Methods Four hundred and thirty-six Australian fathers (M age=37 years, SD=6 years; 34% university educated) of a 2-5 year old child (M age=3.5 years, SD=0.9 years; 53% boys) were recruited via contact with mothers enrolled in existing research projects or a University staff and student email list. Data were collected from fathers via a self-report questionnaire. Descriptive and hierarchical linear regression analyses were conducted. Results The majority of fathers reported that the family often/mostly ate meals together (79%). Many fathers perceived that they were responsible at least half of the time for feeding their child in terms of organizing meals (42%); amount offered (50%) and deciding if their child eats the ‘right kind of foods’ (60%). Time spent in paid employment was inversely associated with how frequently fathers ate meals with their child (β=-0.23, p<0.001); however, both higher perceived responsibility for child feeding (β=-0.16, p<0.004) and a more involved and positive attitude toward their role as a father (β=0.20, p<0.001) were positively related to how often they ate meals with their child, adjusting for a range of paternal and child covariates, including time spent in paid employment. Conclusions Fathers from a broad range of educational backgrounds appear willing to participate in research studies on child feeding. Most fathers were engaged and involved in family meals and child feeding. This suggests that fathers, like mothers, should be viewed as potential agents for the implementation of positive feeding practices within the family.

Dads at the dinner table a cross-sectional study of Australian fathers' child feeding perceptions and practices

Maternal perceptions and practices regarding child feeding have been extensively studied in the context of childhood overweight and obesity. To date, there is scant evidence on the role of fathers in child feeding. This cross-sectional study aimed to identify whether characteristics of fathers and their concerns about their children’s risk of overweight were associated with child feeding perceptions and practices. Questionnaires were used to collect data from 436 Australian fathers (mean age = 37 years, SD = 6) of a child (53% boys) aged between 2-5 years (M = 3.5 years, SD = 0.9). These data included a range of demographic variables and selected subscales from the Child Feeding Questionnaire on concern about child weight, perceived responsibility for child feeding and controlling practices (pressure to eat and restriction). Multivariable linear regression was used to examine associations between demographic variables and fathers’ feeding perceptions and practices. Results indicated that fathers’ who were more concerned about their child becoming overweight reported higher perceived responsibility for child feeding and were more controlling of what and how much their child eats. Greater time commitment to paid work, possessing a health care card (indicative of socioeconomic disadvantage) and younger child age were associated with fathers’ perceiving less responsibility for feeding. Factors such as paternal BMI and education level, as well as child gender were not associated with feeding perceptions or practices. This study contributes to the extant literature on fathers’ role in child feeding, revealing several implications for research and interventions in the child feeding field.

Validation of a new tool to measure responsiveness and structure in the feeding context : the Authoritative Feeding Practices Questionnaire

How mothers interact with their toddlers around food lays the foundations for healthy eating and healthy weight gain in later life. This research involving 467 Australian first-time mothers of 2-year-old children resulted in the development of a new self-report tool, the Authoritative Feeding Practices Questionnaire, assessing maternal responsive feeding and mealtime structure. Secondary analysis of the NOURISH randomised controlled trial included theory-driven item selection, confirmatory factor analysis, evaluation of psychometric properties and construct validation. The result is a brief, reliable and valid new tool for evaluating the maternal feeding practices that support children to become healthy, independent eaters.

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...

Platinum-based chemotherapy in metastatic breast cancer : current status

Cisplatin and carboplatin are active in previously untreated patients with metastatic breast cancer (MBC) with mean response rates (RRs) of 50 and 32%, respectively. In pretreated patients the RR to cisplatin/carboplatin monotherapy declines markedly to <10%. Cisplatin and carboplatin have been combined with many other cytotoxics. In first-line setting high activity has been observed in combination with taxanes or vinorelbine (RRs consistently ∼60%). It appears that these newer combinations are superior to older regimens with etoposide (RRs 30 to 50%) or 5-fluorouracil (RRs 40 to 60%). Cisplatin-/carboplatin-based regimens with infusional 5-FU and epirubicin/paclitaxel/vinorelbine achieve high RRs of around 60 to 80%. However these regimens are difficult to administer in all patients because they require central venous access for continuous 5-FU infusion. In pretreated MBC the combinations of cisplatin-taxane/vinorelbine/gemcitabine or carboplatin-docetaxel/vinorelbine yield RRs of 40 to 50%, which are higher than those achieved with platinum-etoposide/5-FU. In locally advanced disease cisplatin-based regimens achieve very high RRs (>80%). This would suggest that in chemotherapy-naïve patients platinum-based therapy might have an important role to play. Additionally the synergy demonstrated between platinum compounds, taxanes and herceptin, in preclinical and clinical studies is of immense importance and the results of the two ongoing Breast Cancer International Research Group randomized phase III studies are eagerly awaited. These studies may help clarify the role of platinum compounds in the treatment of metastatic and possibly early breast cancer. © 2003 Elsevier Ltd. All rights reserved.

Platinum-based chemotherapy in metastatic breast cancer : the Leicester (UK) experience

Aims: After failure of anthracycline- and taxane-based chemotherapy in metastatic breast cancer, treatment options until recently were limited. Until the introduction of capecitabine and vinorelbine, no standard regimen was available. We conducted a retrospective study to determine the efficacy and toxicity of platinum-based chemotherapy in metastatic breast cancer. Materials and methods: Forty-two women with metastatic breast cancer previously treated with anthracyclines (93%) and/or taxanes (36%) received mitomycin-vinblastine-cisplatin (MVP) (n = 23), or cisplatin-etoposide (PE) (n = 19), as first-, second- and third-line treatment at a tertiary referral centre between 1997 and 2002. Chemotherapy was given every 3 weeks as follows: mitomycin-C (8 mg/m 2) (cycles 1, 2, 4, 6), vinblastine (6 mg/m 2), and cisplatin (50 mg/m 2) all on day 1; and cisplatin (75 mg/m 2) and etoposide (100 mg/m 2) on day 1 and (100 mg/m 2) orally twice a day on days 2-3. Results: The response rate for 40 evaluable patients (MVP: n = 23; PE: n = 17) was 18% (95% confidence interval [CI]: 9-32%). The response rate to MVP was 13% (95% CI: 5-32%, one complete and two partial responses) and to PE 24% (10-47%, four partial responses). Disease stabilised in 43% (26-63%) and 47% (26-69%) of women treated with MVP and PE, respectively. After a median follow-up of 18 months, 37 women (MVP: n = 19; PE: n = 18) died from their disease. Median (range) progression-free survival and overall survival were 6 months (0.4-18.7) and 9.9 months (1.3-40.8), respectively. Median progression-free survival for the MVP and PE groups was 5.5 and 6.2 months (Log-rank, P = 0.82), and median overall survival was 10.2 and 9.4 months (Log-rank, P = 0.46), respectively. The main toxicity was myelosuppression. Grades 3-4 neutropenia was more common in women treated with PE than in women treated with MVP (74% vs 30%; P = 0.012), but the incidence of neutropenic sepsis, relative to the number of chemotherapy cycles, was low (7% overall). The toxicity-related hospitalisation rate was 1.2 admissions per six cycles of chemotherapy. No treatment-related deaths occurred. MVP and PE chemotherapy have modest activity and are safe in women with metastatic breast cancer. © 2005 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.