Genes in the insulin and insulin-like growth factor pathway and odds of metachronous colorectal neoplasia.

Insulin and insulin-like growth factor (IGF) genes are implicated in colorectal carcinogenesis. Gene-by-gene interactions that influence the insulin/IGF pathways were hypothesized as modifiers of colorectal neoplasia risk. We built a classification tree to detect interactions in 18 IGF and insulin pathway-related genes and metachronous colorectal neoplasia among 1,439 subjects pooled from two chemoprevention trials. The probability of colorectal neoplasia was greatest (71.8%) among carriers of any A allele for rs7166348 (IGF1R) and AA genotype for rs1823023 (PIK3R1). In contrast, carriers of any A at rs7166348 (IGF1R), any G for the PIK3R1 variant, and AA for rs10426094 (INSR) had the lowest probability (14.3%). Logistic regression modeling showed that any A at rs7166348 (IGF1R) with the AA genotype at rs1823023 (PIK3R1) conferred the highest odds of colorectal neoplasia (OR 3.7; 95% CI 2.2-6.5), compared with carriage of GG at rs7166348 (IGF1R). Conversely, any A at rs7166348 (IGFR1), any G allele at rs1823023 (PIK3R1), and the AA genotype at rs10426094 (INSR) conferred the lowest odds (OR 0.22; 95% CI 0.07-0.66). Stratifying the analysis by parent study and intervention arm showed highly consistent trends in direction and magnitude of associations, with preliminary evidence of genotype effects on measured IGF-1 levels in a subgroup of subjects. These results were compared to those from multifactor dimensionality reduction, which identified different single nucleotide polymorphisms in the same genes (INSR and IGF1R) as effect modifiers for colorectal neoplasia. These results support a role for genetic interactions in the insulin/IGF pathway genes in colorectal neoplasia risk.

Vitamin D and breast cancer recurrence in the Women's Healthy Eating and Living (WHEL) Study.

BACKGROUND: There is a paucity of research evaluating the relation between vitamin D and recurrence of breast cancer after treatment. OBJECTIVE: This study was designed to evaluate the associations between circulating concentrations of 25-hydroxyvitamin D [25(OH)D] and dietary, supplemental, and total intake of vitamin D and recurrent or new breast cancer events within the Women's Healthy Eating and Living (WHEL) Study. DESIGN: A prospective cohort study design (n = 3085) was used to evaluate the relation between dietary, supplemental, and total vitamin D intake and recurrent breast cancer, and a nested case-control study with 512 matched pairs was used for analysis of the association between 25(OH)D and breast cancer recurrence. RESULTS: No relation between 25(OH)D and breast cancer recurrence was observed. Compared with women with serum concentrations of 25(OH)D ≥ 30 ng/mL, adjusted odds ratios (95% CI) for breast cancer recurrence were 1.14 (0.57, 2.31) for those with concentrations < 10 ng/mL, 1.00 (0.68-1.48) for concentrations ≥ 10 and < 20 ng/mL, and 1.05 (0.76, 1.47) for concentrations ≥ 20 and < 30 ng/mL. No significant associations were observed when analyses were stratified by pre- and postmenopausal status or for local, regional, or distant recurrence or death. Vitamin D intake was not related to breast cancer recurrence overall, although for premenopausal women there was a significant inverse association between dietary vitamin D intake and recurrence (P for trend = 0.02). CONCLUSION: These results do not provide support for a relation between concentrations of 25(OH)D after treatment and the recurrence of breast cancer. This trial is registered at clinicaltrials.gov for the WHEL Study as NCT00003787.

Genetic variation in the retinoid X receptor and calcium-sensing receptor and risk of colorectal cancer in the Colon Cancer Family Registry.

Genetic variants in the calcium/vitamin D metabolic pathway may be related to risk for colorectal cancer. While several investigations of vitamin D receptor (VDR) polymorphisms and colorectal cancer have been conducted, no studies to date have evaluated the association of genetic variation in the heterodimer partner for VDR, the retinoid X receptor (RXR). Another important gene in this pathway is the calcium-sensing receptor (CASR). Employing a discordant-sibship case-control design, we examined the association between single nucleotide polymorphisms (SNPs) in RXRA and CASR and risk for colorectal cancer overall and by colorectal subsite and microsatellite instability (MSI) status using data from the Colon Cancer Family Registry. No gene-level relationships between RXRA or CASR and colorectal cancer overall were observed. However, for RXRA SNP rs7861779, a high-interest SNP selected for study a priori, there was a statistically significantly increased risk for proximal colorectal cancer among those with at least one A allele [odds ratio (OR) = 1.42; 95% confidence interval (CI) = 1.03-1.97]. Another selected RXRA SNP, rs12004589, was significantly associated with risk of MSI-high cancers (OR = 2.27; 95% CI = 1.13-4.56). Additionally, CASR SNP rs1801726 was significantly associated with a reduced risk for rectal cancer (OR = 0.53; 95% CI = 0.29-0.96). These results provide support that RXRA SNPs rs7861779 and rs12004589 and CASR SNP rs1801726 may be important markers for colorectal neoplasia. Further work is needed to elucidate their role in the carcinogenic pathway.

Genetic polymorphisms in vitamin D receptor VDR/RXRA influence the likelihood of colon adenoma recurrence.

Low circulating levels of vitamin D affect colorectal cancer risk. The biological actions of the hormonal form of vitamin D, 1,25(OH)(2)D(3), are mediated by the vitamin D receptor (VDR), which heterodimerizes with retinoid X receptors (RXR). Using a single nucleotide polymorphism (SNP) tagging approach, we assessed the association between genetic variations in RXRA and VDR and odds of recurrent (metachronous) colorectal neoplasia in a pooled population of two studies. A total of 32 tag SNPs in RXRA and 42 in VDR were analyzed in 1,439 participants. A gene-level association was observed for RXRA and any (P = 0.04) or proximal (P = 0.03) metachronous neoplasia. No gene-level associations were observed for VDR, nor was any single SNP in VDR related to any metachronous adenoma after correction for multiple comparisons. In contrast, the association between RXRA SNP rs7861779 and proximal metachronous neoplasia was of borderline statistical significance [odds ratio (OR), 0.68; 95% confidence interval (95% CI), 0.53-0.86; unadjusted P = 0.001; adjusted P = 0.06], including when observed independently in each individual study. Haplotypes within linkage blocks of RXRA support an approximately 30% reduction in odds of metachronous neoplasia arising in the proximal colon among carriers of specific haplotypes, which was strongest (OR(proximal), 0.67; 95% CI, 0.52-0.86) for carriers of a CGGGCA haplotype (rs1805352, rs3132297, rs3132296, rs3118529, rs3118536, and rs7861779). Our results indicate that allelic variation in RXRA affects metachronous colorectal neoplasia, perhaps of particular importance in the development of proximal lesions.

Natural history of asymptomatic left ventricular systolic dysfunction in the community.

BACKGROUND: Information is limited regarding the rates of progression to congestive heart failure (CHF) and death in individuals with asymptomatic left ventricular systolic dysfunction (ALVD). We sought to characterize the natural history of ALVD, by studying unselected individuals with this condition in the community. METHODS AND RESULTS: We studied 4257 participants (1860 men) from the Framingham Study who underwent routine echocardiography. The prevalence of ALVD (visually estimated ejection fraction [EF]50%, n=4128) and ALVD (n=129) were 0.7 and 5.8 per 100 person-years, respectively. After adjustment for cardiovascular disease risk factors, ALVD was associated with a hazards ratio (HR) for CHF of 4.7 (95% CI 2.7 to 8.1), compared with individuals without ALVD. An elevated risk of CHF after ALVD was observed even in individuals without prior myocardial infarction or valvular disease, with an adjusted HR of 6.5 (CI 3.1 to 13.5). Mild ALVD (EF 40% to 50%, n=78) and moderate-to-severe ALVD (EF <40%, n=51) were associated with adjusted HRs for CHF of 3.3 (CI 1.7 to 6.6) and 7.8 (CI 3.9 to 15.6), respectively. ALVD was also associated with an increased mortality risk (adjusted HR 1.6, CI 1.1 to 2.4). The median survival of ALVD subjects was 7.1 years. CONCLUSIONS: Individuals with ALVD in the community are at high risk of CHF and death, even when only mild impairment of EF is present. Additional studies are needed to define optimal therapy for mild ALVD.