Interactive effect of TLR SNPs and exposure to sexually transmitted infections on prostate cancer risk in Jamaican men.

BACKGROUND: Prostate cancer (PC) risk increases with African ancestry and a history of sexually transmitted infections (STIs). Also, single-nucleotide polymorphisms (SNPs) in toll-like receptor (TLR) genes influence PC risk. This pilot study explores interactions between STIs and TLR-related SNPs in relation to PC risk among Jamaican men. METHODS: This case-control study evaluates two TLR related SNPs in 356 Jamaican men (194 controls and 162 cases) with or without history of STIs using stepwise penalized logistic regression in multivariable analyses. RESULTS: Age (odds ratio [OR] = 1.08; 95% confidence interval [CI]: 1.04-1>.12; p < .001) and IRF3_rs2304206 GG genotype (OR = 0.47; 95% CI: 0.29-0<.78; p = .003) modulated PC risk in people with history of STIs. In the population with no history of STIs, resulting interactions between risk factors did not survive correction for multiple hypothesis testing. CONCLUSION: Overall, an interaction between the IFR3_rs2304206 variant and a history of exposure to STIs leads to greater decrease of PC risk than the presence of polymorphic genotype alone. These findings are suggestive and require further validation. Identification of gene variants along with detection of lifestyle behaviors may contribute to identification of men at a greater risk of PC development in the population.

The impact of genetic variants in inflammatory-related genes on prostate cancer risk among men of African Descent: a case control study.

PURPOSE: Although case-control studies have evaluated the role of variant inflammatory-related loci in prostate cancer, their impact is virtually unknown among men of African descent. To address this, we evaluated the impact of inflammatory cytokine single nucleotide polymorphisms (SNPs) on prostate cancer risk for men of African descent. METHODS: Forty-four SNPs in inflammatory cytokine-associated genes were evaluated among 814 African-American and Jamaican men (279 prostate cancer cases and 535 controls) using Illumina's Golden gate genotyping system. Individual SNP effects were evaluated using logistic regression analysis. RESULTS: Four SNPs were modestly associated with prostate cancer after adjusting for age. In the total population, inheritance of the IL1R2 rs11886877 AA, IL8RB rs11574752 AA, TNF rs1800629 GA + AA, and TNF rs673 GA genotypes modestly increased prostate cancer risk by 1.45 to 11.7-fold relative to the referent genotype. Among U.S. men, age-adjusted dominant, recessive and additive genetic models for the IL1R2 rs11886877 locus were linked to an increase in prostate cancer susceptibility. However, these main effects did not persist after adjusting for multiple hypothesis testing. CONCLUSION: Our preliminary data does not strongly support the hypothesis that inflammatory-related sequence variants influence prostate cancer risk among men of African descent. However, further evaluation is needed to assess whether other variant inflammatory-related genes may contribute to prostate cancer risk and disease progression in larger and ethnically diverse multi-center studies.

Inflammation polymorphisms and prostate cancer risk in Jamaican men: Role of obesity/body size.

African ancestry and obesity are associated with higher risk of prostate cancer (PC). In a pilot study, we explored interactions between obesity (as measured by waist to hip ratio (WHR)) and inflammatory SNPs in relation to PC risk among Jamaican men. This study evaluated 87 chemokine and cytokine associated SNPs in obese and normal weight cases (N=109) and controls (N=102) using a stepwise penalized logistic regression approach in multivariable analyses. Upon stratification by WHR (normal weight (WHR<0.90) or obese (WHR≥0.90)), inheritance of CCR6 rs2023305 AG+GG (OR=1.75, p=0.007), CCR9 rs7613548 AG+GG (OR=1.71, p=0.012) and IL10ra rs2229113 AG+GG (OR=1.45, p=0.01) genotypes was associated with increase in overall or low grade (Gleason score<7) PC risk among normal weight men. These odds were elevated among obese men who possessed the CCR5 rs1799987 AG+GG (OR=1.95, p=0.003) and RNASEL rs12135247 CT+TT genotypes (OR=1.59, p=0.05). CCR7 rs3136685 AG+GG (p=0.032) was associated with a 1.52-1.70 fold increase in the risk of high grade cancer (Gleason score≥7) among obese men. CCR7 variant emerged as an important factor associated with high grade PC risk among obese men in our analyses. Overall, genetic loci found significant in normal weight men were not significant in obese men and vice-versa, partially explaining the role of obesity on PC risk among black men. Also, older age was an important risk factor both in normal weight and obese men but only with regard to low grade PC. Associations of inflammatory SNPs with obesity are suggestive and require further validation in larger cohorts to help develop an understanding of PC risk among obese and non-obese men of African descent.

Chemokine Ligand 5 (CCL5) and chemokine receptor (CCR5) genetic variants and prostate cancer risk among men of African Descent: a case-control study.

BACKGROUND: Chemokine and chemokine receptors play an essential role in tumorigenesis. Although chemokine-associated single nucleotide polymorphisms (SNPs) are associated with various cancers, their impact on prostate cancer (PCA) among men of African descent is unknown. Consequently, this study evaluated 43 chemokine-associated SNPs in relation to PCA risk. We hypothesized inheritance of variant chemokine-associated alleles may lead to alterations in PCA susceptibility, presumably due to variations in antitumor immune responses. METHODS: Sequence variants were evaluated in germ-line DNA samples from 814 African-American and Jamaican men (279 PCA cases and 535 controls) using Illumina's Goldengate genotyping system. RESULTS: Inheritance of CCL5 rs2107538 (AA, GA+AA) and rs3817655 (AA, AG, AG+AA) genotypes were linked with a 34-48% reduction in PCA risk. Additionally, the recessive and dominant models for CCR5 rs1799988 and CCR7 rs3136685 were associated with a 1.52-1.73 fold increase in PCA risk. Upon stratification, only CCL5 rs3817655 and CCR7 rs3136685 remained significant for the Jamaican and U.S. subgroups, respectively. CONCLUSIONS: In summary, CCL5 (rs2107538, rs3817655) and CCR5 (rs1799988) sequence variants significantly modified PCA susceptibility among men of African descent, even after adjusting for age and multiple comparisons. Our findings are only suggestive and require further evaluation and validation in relation to prostate cancer risk and ultimately disease progression, biochemical/disease recurrence and mortality in larger high-risk subgroups. Such efforts will help to identify genetic markers capable of explaining disproportionately high prostate cancer incidence, mortality, and morbidity rates among men of African descent.

Interaction among apoptosis-associated sequence variants and joint effects on aggressive prostate cancer.

BACKGROUND: Molecular and epidemiological evidence demonstrate that altered gene expression and single nucleotide polymorphisms in the apoptotic pathway are linked to many cancers. Yet, few studies emphasize the interaction of variant apoptotic genes and their joint modifying effects on prostate cancer (PCA) outcomes. An exhaustive assessment of all the possible two-, three- and four-way gene-gene interactions is computationally burdensome. This statistical conundrum stems from the prohibitive amount of data needed to account for multiple hypothesis testing. METHODS: To address this issue, we systematically prioritized and evaluated individual effects and complex interactions among 172 apoptotic SNPs in relation to PCA risk and aggressive disease (i.e., Gleason score ≥ 7 and tumor stages III/IV). Single and joint modifying effects on PCA outcomes among European-American men were analyzed using statistical epistasis networks coupled with multi-factor dimensionality reduction (SEN-guided MDR). The case-control study design included 1,175 incident PCA cases and 1,111 controls from the prostate, lung, colo-rectal, and ovarian (PLCO) cancer screening trial. Moreover, a subset analysis of PCA cases consisted of 688 aggressive and 488 non-aggressive PCA cases. SNP profiles were obtained using the NCI Cancer Genetic Markers of Susceptibility (CGEMS) data portal. Main effects were assessed using logistic regression (LR) models. Prior to modeling interactions, SEN was used to pre-process our genetic data. SEN used network science to reduce our analysis from > 36 million to < 13,000 SNP interactions. Interactions were visualized, evaluated, and validated using entropy-based MDR. All parametric and non-parametric models were adjusted for age, family history of PCA, and multiple hypothesis testing. RESULTS: Following LR modeling, eleven and thirteen sequence variants were associated with PCA risk and aggressive disease, respectively. However, none of these markers remained significant after we adjusted for multiple comparisons. Nevertheless, we detected a modest synergistic interaction between AKT3 rs2125230-PRKCQ rs571715 and disease aggressiveness using SEN-guided MDR (p = 0.011). CONCLUSIONS: In summary, entropy-based SEN-guided MDR facilitated the logical prioritization and evaluation of apoptotic SNPs in relation to aggressive PCA. The suggestive interaction between AKT3-PRKCQ and aggressive PCA requires further validation using independent observational studies.

Recent patents in Toll-like receptor pathways and relevance to cancer.

The first lines of defense in the human innate immune system are membrane receptors called Toll-like receptors (TLRs). This family of receptors functions as primary sensors to recognize microbial pathogens. Subsequent binding of ligands to TLRs lend to the activation of cellular signaling pathways that regulate expression of genes related to inflammation and immunity. The discovery and supporting evidence of functional and structural diversity suggests TLRs are key participants in cellular immunity and are important to various medical conditions including the tumor microenvironment. TLR heterogeneity emphasizes the role of these receptors and suggests a new opportunity to develop therapies targeting specific or multiple TLRs that may contribute to the treatment of a myriad of diseases including various cancers. In this article, we intend to focus on a number of recently issued patents related to TLRs and to propose the relevance of these patents to novel treatments for cancers.