Melatonin supplementation and oxidative DNA damage repair capacity among night shift workers: a randomised placebo-controlled trial.

Objectives: A decreased ability to repair oxidative DNA damage, due to melatonin suppression, is a compelling mechanism by which night shift workers are at an increased risk of cancer. We sought to determine if melatonin supplementation would improve oxidative DNA damage repair among night shift workers.

Methods: We conducted a parallel-arm randomised placebo-controlled trial of melatonin supplementation among 40 night shift workers.

Interactions between exposure to polycyclic aromatic hydrocarbons and xenobiotic metabolism genes, and risk of breast cancer.

Purpose: Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental pollutants associated with multiple cancers, including female breast cancer. Several xenobiotic metabolism genes (XMGs), including the CYP450 family, play an important role in activating and detoxifying PAHs, and variations in the activity of the enzymes they encode can impact this process. This study aims to examine the association between XMGs and breast cancer, and to assess whether these variants modify the effects of PAH exposure on breast cancer risk.

Tattoos and Hematologic Malignancies in British Columbia, Canada.

Background: Tattoos may cause a variety of adverse reactions in the body, including immune reactions and infections. However, it is unknown whether tattoos may increase the risk of lymphatic cancers such as non-Hodgkin lymphoma (NHL) and multiple myeloma.

Methods: Participants from two population-based case-control studies were included in logistic regression models to examine the association between tattoos and risk of NHL and multiple myeloma.

Mammographic density parameters and breast cancer tumor characteristics among postmenopausal women.

Purpose: Mammographic density is an important breast cancer risk factor, although it is not clear whether the association differs across breast cancer tumor subtypes. We examined the association between indicators of mammographic density and breast cancer risk by tumor subtype among postmenopausal women by investigating heterogeneity across tumor characteristics.

Methods: Mammographic density measures were determined for 477 breast cancer cases and 588 controls, all postmenopausal, in Vancouver, British Columbia, using digitized screening mammograms and Cumulus software.

Genetic variants in genes related to inflammation, apoptosis and autophagy in breast cancer risk.

Background: Inflammation contributes to breast cancer development through its effects on cell damage. This damage is usually dealt with by key genes involved in apoptosis and autophagy pathways.

Methods: We tested 206 single nucleotide polymorphisms (SNPs) in 54 genes related to inflammation, apoptosis and autophagy in a population-based breast cancer study of women of European (658 cases and 795 controls) and East Asian (262 cases and 127 controls) descent.

Women's occupational exposure to polycyclic aromatic hydrocarbons and risk of breast cancer.

Objective: To estimate the association between occupational polycyclic aromatic hydrocarbon (PAH) exposure and female breast cancer.

Methods: Lifetime work histories for 1130 cases and 1169 controls from British Columbia and Ontario (Canada) were assessed for PAH exposure using a job-exposure matrix based on compliance measurements obtained during US Occupational Safety and Health Administration workplace safety inspections.

Results: Exposure to any level of PAHs was associated with an increased risk of breast cancer (OR=1.

Mammographic non-dense area and breast cancer risk in postmenopausal women: a causal inference approach in a case-control study.

Purpose: The association between high mammographic density (MD) and elevated breast cancer risk is well established. However, the role of absolute non-dense area remains unclear. We estimated the effect of the mammographic non-dense area and other density parameters on the risk of breast cancer.

Polymorphisms of Insulin-Like Growth Factor 1 Pathway Genes and Breast Cancer Risk.

Genetic variants of insulin-like growth factor 1 (IGF1) pathway genes have been shown to be associated with breast density and IGF1 levels and, therefore, may also influence breast cancer risk via pro-survival signaling cascades. The aim of this study was to investigate associations between IGF1 pathway single nucleotide polymorphisms (SNPs) and breast cancer risk among European and East Asian women, and potential interactions with menopausal status and breast tumor subtype. Stratified analyses of 1,037 cases and 1,050 controls from a population-based case-control study were conducted to assess associations with breast cancer for 22 SNPs across 5 IGF1 pathway genes in European and East Asian women.

Genetic variation in vitamin D-related genes and risk of breast cancer among women of European and East Asian descent.

Studies of vitamin D-related genetic variants and breast cancer have been inconsistent. This study aimed to investigate associations of vitamin D-related polymorphisms and breast cancer risk among European and East Asian women and potential interactions with menopausal status and breast tumour subtypes. Data from a case-control study of breast cancer (1037 cases and 1050 controls) were used to assess relationships between 21 polymorphisms in two vitamin D-related genes (GC and VDR) and breast cancer risk.

A case-control study of lifetime light intensity physical activity and breast cancer risk.

Purpose: Physical activity reduces breast cancer risk, although most evidence is for activity in the moderate-to-vigorous intensity range. The effect of light intensity physical activity (LIPA) is unknown. We aimed to determine the association between self-reported lifetime LIPA and pre- and post-menopausal breast cancer risk.

Increased risk of breast cancer associated with long-term shift work in Canada.

Objectives: Long-term night work has been suggested as a risk factor for breast cancer; however, additional studies with more comprehensive methods of exposure assessment to capture the diversity of shift patterns are needed. As well, few previous studies have considered the role of hormone receptor subtype.

Methods: Relationships between night shift work and breast cancer were examined among 1134 breast cancer cases and 1179 controls, frequency-matched by age in Vancouver, British Columbia, and Kingston, Ontario.

Moderate-to-vigorous intensity physical activity across the life course and risk of pre- and post-menopausal breast cancer.

Moderate-to-vigorous intensity physical activity (MVPA) reduces breast cancer risk, although the effects of MVPA in different settings across the life course and how they may differ by menopausal status are unclear. This gap was addressed using data from a case-control study of 1,110 incident breast cancer cases and 1,172 cancer-free controls, frequency matched by age, from Vancouver and Kingston, Canada. In Vancouver, cases were recruited from the British Columbia Cancer Registry and controls from the Screening Mammography Program of British Columbia and in Kingston cases and controls were recruited from a breast assessment center.

Shift work, circadian gene variants and risk of breast cancer.

Circadian (clock) genes have been linked with several functions relevant to cancer, and epidemiologic research has suggested relationships with breast cancer risk for variants in NPAS2, CLOCK, CRY2 and TIMELESS. Increased breast cancer risk has also been observed among shift workers, suggesting potential interactions in relationships of circadian genes with breast cancer. Relationships with breast cancer of 100 SNPs in 14 clock-related genes, as well as potential interactions with shift work history, were investigated in a case-control study (1042 cases, 1051 controls).

Genetic variation in the NBS1, MRE11, RAD50 and BLM genes and susceptibility to non-Hodgkin lymphoma.

Background: Translocations are hallmarks of non-Hodgkin lymphoma (NHL) genomes. Because lymphoid cell development processes require the creation and repair of double stranded breaks, it is not surprising that disruption of this type of DNA repair can cause cancer. The members of the MRE11-RAD50-NBS1 (MRN) complex and BLM have central roles in maintenance of DNA integrity.

GBV-C/hepatitis G virus infection and non-Hodgkin lymphoma: a case control study.

We investigated whether there was an association between GBV-C viremia and the development of non-Hodgkin lymphoma (NHL) in 553 NHL cases and 438 controls from British Columbia, Canada. Cases were aged 20-79, diagnosed between March 2000 and February 2004, and resident in Greater Vancouver or Victoria. Cases and controls were tested for GBV-C RNA by RT-PCR and positive samples were genotyped.

Interaction between organochlorines and the AHR gene, and risk of non-Hodgkin lymphoma.

Background: Plasma organochlorines have been implicated to increase the risk of non-Hodgkin lymphoma (NHL), and interaction with the aryl hydrocarbon receptor gene (AHR) may modify this risk.

Methods: In this case-control study conducted in British Columbia, Canada, five single nucleotide polymorphisms (SNPs) of AHR were genotyped in 422 NHL cases and 459 controls to measure the association between individual SNPs, haplotypes, and risk of NHL. Pre-chemotherapy organochlorine levels were measured and gene-environment interaction analysis was performed.

Hepatitis C virus and risk of non-Hodgkin lymphoma in British Columbia, Canada.

We investigated Hepatitis C virus (HCV) seropositivity and the risk of non-Hodgkin lymphoma (NHL) in a population-based case-control study in British Columbia, Canada. Cases were aged 20-79, diagnosed between March 2000 and February 2004, and resident in greater Vancouver or Victoria. Cases with HIV or a prior transplant were excluded.

Organochlorines and risk of non-Hodgkin lymphoma.

Organochlorine chemicals and polychlorinated biphenyls (PCBs) have been suspected as possible risk factors for non-Hodgkin lymphoma (NHL). We investigated PCBs and organochlorine pesticides and risk of NHL in a population-based case-control study in British Columbia, Canada. Congeners of PCBs (including dioxinlike congeners) and pesticides or pesticide metabolites were measured in plasma of 422 pretreatment cases and 460 control subjects.