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Articles by M. E Martinez
Total Records ( 3 ) for M. E Martinez
  P. A Thompson , B. C Wertheim , D. J Roe , E. L Ashbeck , E. T Jacobs , P Lance , M. E Martinez and D. S. Alberts
 

Purpose: Ursodeoxycholic acid (UDCA) was one of the earliest agents investigated as a drug for colorectal cancer prevention. However, UDCA failed to show efficacy to prevent the development of colorectal adenomas in a large, phase III, randomized, placebo-controlled trial. We re-evaluated the effect of UDCA in men and women separately, based on sex-specific differences in bile acid metabolism and suspected variation in etiologic factors contributing to colorectal cancer risk.

Experimental Design: We conducted a secondary analysis of the efficacy of UDCA to prevent colorectal adenoma in men (n = 804) and women (n = 388).

Results: We found no reduction in risk of any metachronous adenoma with UDCA treatment in men or women. However, UDCA treatment significantly lowered the odds of advanced lesions [odds ratio (OR), 0.62; 95% confidence interval (CI), 0.43-0.89] in men, but not women. We also observed significantly higher odds of advanced lesions with UDCA treatment in women who were younger (age, <65 years; OR, 3.24; 95% CI, 1.10-9.56), obese (body mass index, ≥30 kg/m2; OR, 5.45; 95% CI, 1.42-20.9), or in the highest tertile of total dietary fat (≥56.2 g/day; OR, 3.48; 95% CI, 1.35-8.95). In a multivariate model, the interactive effect of fat intake accounted for the modulating effects of age and body mass index in women.

Conclusion: Our findings support the use of UDCA for preventing advanced colorectal adenomas in men. The increased odds of adenoma among women with high fat intake suggest a previously unrecognized harm that warrants further study, especially given the chronic exposure to UDCA in patients with primary biliary cirrhosis and the increasing investigational use of UDCA for several other conditions.

  E. T Jacobs , M. E Martinez , P. T Campbell , D. V Conti , D Duggan , J. C Figueiredo , R. W Haile , E. C LeRoy , J. N Poynter , P. A Thompson and J. A. Baron
 

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.

  P. T Campbell , E. T Jacobs , C. M Ulrich , J. C Figueiredo , J. N Poynter , J. R McLaughlin , R. W Haile , E. J Jacobs , P. A Newcomb , J. D Potter , L Le Marchand , R. C Green , P Parfrey , H. B Younghusband , M Cotterchio , S Gallinger , M. A Jenkins , J. L Hopper , J. A Baron , S. N Thibodeau , N. M Lindor , P. J Limburg , M. E Martinez and for the Colon Cancer Family Registry
  Background

Being overweight or obese is an established risk factor for colorectal cancer, more so for men than for women. Approximately 10%–20% of colorectal tumors display microsatellite instability (MSI), defined as the expansion or contraction of small repeated sequences in the DNA of tumor tissue relative to nearby normal tissue. We evaluated associations between overweight or obesity and colorectal cancer risk, overall and by tumor MSI status.

Methods

The study included 1794 case subjects with incident colorectal cancer who were identified through population-based cancer registries and 2684 of their unaffected sex-matched siblings as control subjects. Recent body mass index (BMI), BMI at age 20 years, and adult weight change were derived from self-reports of height and weight. Tumor MSI status, assessed at as many as 10 markers, was obtained for 69.7% of the case subjects and classified as microsatellite (MS)-stable (0% of markers unstable; n = 913), MSI-low (>0% but <30% of markers unstable; n = 149), or MSI-high (≥30% of markers unstable; n = 188). Multivariable conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). All statistical tests were two-sided.

Results

Recent BMI, modeled in 5 kg/m2 increments, was positively associated with risk of colorectal cancer for men and women combined (OR = 1.24; 95% CI = 1.15 to 1.34), for women only (OR = 1.20; 95% CI = 1.10 to 1.32), and for men only (OR = 1.30; 95% CI = 1.15 to 1.47). There was no interaction with sex (P = .22). Recent BMI, per 5 kg/m2, was positively associated with the risk of MS-stable (OR = 1.38; 95% CI = 1.24 to 1.54) and MSI-low (OR = 1.33; 95% CI = 1.04 to 1.72) colorectal tumors, but not with the risk of MSI-high tumors (OR = 1.05; 95% CI = 0.84 to 1.31).

Conclusion

The increased risk of colorectal cancer associated with a high BMI might be largely restricted to tumors that display the more common MS-stable phenotype, suggesting further that colorectal cancer etiology differs by tumor MSI status.

 
 
 
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