Serum carbon and nitrogen stable isotopes as potential biomarkers of dietary intake and their relation with incident type 2 diabetes: the EPIC-Norfolk study

BACKGROUND

Stable-isotope ratios of carbon (¹³C/¹²C, expressed as δ¹³C) and nitrogen (¹⁵N/¹⁴N, or δ¹⁵N) have been proposed as potential nutritional biomarkers to distinguish between meat, fish, and plant-based foods.

OBJECTIVE

The objective was to investigate dietary correlates of δ¹³C and δ¹⁵N and examine the association of these biomarkers with incident type 2 diabetes in a prospective study.

DESIGN

Serum δ¹³C and δ¹⁵N (‰) were measured by using isotope ratio mass spectrometry in a case-cohort study (n = 476 diabetes cases; n = 718 subcohort) nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk population-based cohort. We examined dietary (food-frequency questionnaire) correlates of δ¹³C and δ¹⁵N in the subcohort. HRs and 95% CIs were estimated by using Prentice-weighted Cox regression.

RESULTS

Mean (±SD) δ¹³C and δ¹⁵N were -22.8 ± 0.4‰ and 10.2 ± 0.4‰, respectively, and δ¹³C (r = 0.22) and δ¹⁵N (r = 0.20) were positively correlated (P < 0.001) with fish protein intake. Animal protein was not correlated with δ¹³C but was significantly correlated with δ¹⁵N (dairy protein: r = 0.11; meat protein: r = 0.09; terrestrial animal protein: r = 0.12, P ≤ 0.013). δ¹³C was inversely associated with diabetes in adjusted analyses (HR per tertile: 0.74; 95% CI: 0.65, 0.83; P-trend < 0.001], whereas δ¹⁵N was positively associated (HR: 1.23; 95% CI: 1.09, 1.38; P-trend = 0.001).

CONCLUSIONS

The isotope ratios δ¹³C and δ¹⁵N may both serve as potential biomarkers of fish protein intake, whereas only δ¹⁵N may reflect broader animal-source protein intake in a European population. The inverse association of δ¹³C but a positive association of δ¹⁵N with incident diabetes should be interpreted in the light of knowledge of dietary intake and may assist in identifying dietary components that are associated with health risks and benefits.

Reproductive risk factors and oestrogen/progesterone receptor-negative breast cancer in the Breast Cancer Family Registry

BACKGROUND

Oestrogen receptor (ER)- and progesterone receptor (PR)-negative (ER-PR-) breast cancer is associated with poorer prognosis compared with other breast cancer subtypes. High parity has been associated with an increased risk of ER-PR- cancer, but emerging evidence suggests that breastfeeding may reduce this risk. Whether this potential breastfeeding benefit extends to women at high risk of breast cancer remains critical to understand for prevention.

METHODS

Using population-based ascertained cases (n=4011) and controls (2997) from the Breast Cancer Family Registry, we examined reproductive risk factors in relation to ER and PR status.

RESULTS

High parity (≥3 live births) without breastfeeding was positively associated only with ER-PR- tumours (odds ratio (OR)=1.57, 95% confidence interval (CI), 1.10-2.24); there was no association with parity in women who breastfed (OR=0.93, 95% CI 0.71-1.22). Across all race/ethnicities, associations for ER-PR- cancer were higher among women who did not breastfeed than among women who did. Oral contraceptive (OC) use before 1975 was associated with an increased risk of ER-PR- cancer only (OR=1.32, 95% CI 1.04-1.67). For women who began OC use in 1975 or later there was no increased risk.

CONCLUSIONS

Our findings support that there are modifiable factors for ER-PR- breast cancer and that breastfeeding in particular may mitigate the increased risk of ER-PR- cancers seen from multiparity.

Testing for her2 in breast cancer: current pathology challenges faced in Canada

This review is designed to highlight several key challenges in the diagnosis of human epidermal growth factor receptor 2 (her2)-positive breast cancer currently faced by pathologists in Canada: Pre-analysis issues affecting the accuracy of her2 testing in non-excision sample types: core-needle biopsies, effusion samples, fine-needle aspirates, and bone metastasesher2 testing of core-needle biopsies compared with surgical specimensCriteria for retesting her2 status upon disease recurrenceLiterature searches for each topic were carried out using the medline, Embase, International Pharmaceutical Abstracts, and biosis databases. In addition, the congress databases of the American Society of Clinical Oncology (2005-2011) and the San Antonio Breast Cancer Symposium (2007-2011) were searched for relevant abstracts.All authors are expert breast pathologists with extensive experience of her2 testing, and several participated in the development of Canadian her2 testing guidelines. For each topic, the authors present an evaluation of the current data available for the guidance of pathology practice, with recommendations for the optimization or improvement of her2 testing practice.

Abstract P2-11-01: Molecular Profiling Identifies Differentially Expressed Genes between Normal Breast Tissue from BRCA Carriers and Women at Population Risk

Background: Women found to carry a BRCA1 or BRCA2 gene mutation are at significant risk of future breast cancer (BC). Prophylactic mastectomy (PM) remains the most effective risk reducing strategy in that setting. Thus far, there are no data available identifying changes in gene expression profiles prior to the onset of BC in these women using microarray technology.

Material and methods : In this pilot study, we prospectively collected PM specimens from BRCA1/2 mutation carriers (n=21), and reduction mammoplasty (RM) specimens from healthy controls at population risk of breast cancer (n=13). Samples were collected from all 4 quadrants (fresh frozen) and careful histological examination was conducted. Selected samples (most dense parenchymal tissue) were sent for microarray analyses (19K chip, http://www.uhnres.utoronto.ca/facilities/index.htm). We compared the molecular profiles of breast tissue obtained from these two groups using two approaches: 1) microarray analysis for a global assessment of gene expression, and 2) gene set analysis to identify differences based on cellular function and biologic themes. Results: Women in each group were of similar age (p=NS). No invasive cancer was identified. In histologically normal breast tissue, class comparison identified differential gene expression between RM and PM tissues. Gene set analysis of five collections including MSigDB C2, C4, cytobands, Stanford 5Mb chromosomal tiles and KEGG database identified 22 significant gene sets. Nine sets were overexpressed and 13 sets were underexpressed in PM tissues (FDR &lt; 0.2; p &lt; 0.012). We found overexpression of genes relating to proliferation and transcription specifically in the PM tissues enriched for Gene Ontology annotations. The top 200 genes ranked by SAM were also examined by pathway analysis that showed high enrichment for cancer related pathways. All three approaches implicated T cell receptor signaling and a TSG101-stathmin breast cancer related pathway as contributing to the differential molecular profiles between RM and PM tissues.

Discussion: We have shown differential expression of single genes as well as cancer related biologic pathways (using microarray and gene set analyses) between normal breast tissue from BRCA1/2 mutation carriers (at high risk of BC) and healthy controls (at population risk of BC). These differences may represent early molecular defects of genetic pathways potentially involved in the early stages of breast carcinogenesis in women at hereditary high risk or may represent the result of BRCA1/2 haploinsufficiency. These results support the hypothesis that molecular pathways leading to BC formation are unique to BRCA1/2 carriers. This information may help the development of innovative preventive strategies for BRCA carriers in the future.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-11-01.

Granular cell tumour of the breast: MRI findings and review of the literature

Granular cell tumours (GCTs) are uncommon, usually benign neoplasms that can mimic malignancy on breast imaging. GCTs can originate anywhere in the body but are most frequently found in the head and neck area, particularly in the oral cavity. When occurring in the breast, as occurs in 5-8% of all cases of GCT, the clinical presentation is similar to that of a primary breast carcinoma. We report a case of granular cell tumour of the breast presenting as a suspicious lesion on breast imaging, and review the MRI features of GCTs.

Effect of increasing silver content in phosphate-based glasses on biofilms ofStreptococcus sanguis

Silver is a powerful antibacterial ion that may be useful for dealing with localized infections, such as periodontitis. However, the use of silver in this role could be significantly improved by the development of an effective means of delivery. Phosphate-based glasses may provide a means of delivering the ions in a controlled manner. In our study, we have examined the effect of increasing silver content in phosphate-based glasses on biofilms of Streptococcus sanguis. Glasses of nominally the same dissolution rate were doped with silver at 1, 5,10, and 15 mol % and the number of colony-forming units (CFUs) determined after 6 and 24 h in a constant depth film fermenter (CDFF). The 1 mol % silver showed little change between 6 and 24 h. However, only 0.5 log CFUs were present on the glass containing 5 mol % at 6 h, and this reduced to virtually zero at 24 h. Few viable bacteria were found on the 10 mol % glass at both 6 and 24 h. The 15 mol % glass was investigated in this experiment, but no viable counts were detected. In a second set of experiments, glasses with 10 and 15 mol % silver were tested in the CDFF for up to 192 h. For the 10 mol % silver glass, there was approximately 0.8 log CFUs on this glass, which dropped to almost zero at 50 h. This was approximately 1.5-2.0 log reduction in CFUs compared to controls, and this difference was maintained for the first 50 h. After 50 h, there was a slow increase in the CFUs on all samples. However, CFUs on the 10 mol % silver glass were still suppressed up to 192 h compared to the controls. However, both controls also exhibited a decrease in viable counts at 50 h; this may have been due to carryover of silver into the control sample holders. However, this was minimized by the specimen layout in the CDFF and by having gaps between specimen sets. For the 15 mol % silver glass, counts for both this glass and the controls decreased to virtually zero between 24 and 48 h, but the numbers slowly increased up to 170 h, but the number of CFUs was suppressed compared to the 10 mol % glass at the same time point. The decrease seen is clearly the effect of the silver ions; however, the slow increase in CFUs may be accounted for by the biofilms forming thick layers on top of the glass discs inhibiting the release of ions from the glass by forming a "sacrificial layer" through which further ions have to diffuse.

The effect of increasing copper content in phosphate-based glasses on biofilms of Streptococcus sanguis

This paper reports the effect of a series of phosphate-based glasses based on the Na(2)O-CaO-P(2)O(5) system doped with increasing amounts of copper and the effect of this increasing copper content on the viability of an in vitro biofilm of Streptococcus sanguis over an 8 day period in a constant depth film fermenter. The addition of copper to the glass caused the solubility to change, so the glasses were adjusted in order that their solubility in artificial saliva was nominally the same (0.3062 +/- 0.07 mg cm(-2) h(-1)). Initial experiments on glasses with 1.5% and 10% copper showed that after 6 h there was no statistical difference between the copper containing glasses and the non-copper containing glass and HA in terms of the viability of the biofilms. However, at 24 h there was an approximately 0.8-0.9 log reduction in viability of the biofilms grown on the 5% copper glass and an approximately 1.0-1.3 log reduction for the 10% copper containing glass. Further experiments on the glass with 10% copper and another glass with 15% copper were carried out in a time dependent study. For both glasses a clear decrease in viable counts at 24 h was found but for both glasses these returned to levels similar to those of controls. The initial decrease in viability during the first 24 h is likely to be due to the antibacterial effect of the copper and this could be correlated with copper content. The recovery after 24 h is probably due to the dead cells forming a barrier, making diffusion of the antibacterial ions, increasingly difficult. This study has shown that phosphate-based glasses could potentially be used to deliver antibacterial ions to help combat oral infections. Copper, which has been shown to have antibacterial properties, could be incorporated but some development of the glasses used in this investigation may be required. Further work is needed to determine the effectiveness of copper containing glasses on oral bacterial communities.