The Cumulative Effect of Gene-Gene and Gene-Environment Interactions on the Risk of Prostate Cancer in Chinese Men

Genetic variants of antioxidant and xenobiotic metabolizing enzymes and their association with prostate cancer: A meta-analysis and functional in silico analysis

The development and progression of prostate cancer (PCa) depends on complex interactions between genetic, environmental and dietary factors that modulate the carcinogenesis process. Interactions between chemical exposures and genetic polymorphisms in genes encoding xenobiotic metabolizing enzymes (XME), antioxidant enzymes and DNA repair enzymes have been reported as the main drivers of cancer. Thus, a better understanding of the causal risk factors for PCa will provide avenues to identify men at increased risk and will contribute to develop effective detection and prevention methods. We performed a meta-analysis on 17,518 cases and 42,507 controls obtained from 42 studies to determine whether seven SNPs and one CNV pertaining to oxidative stress, xenobiotic detoxification and DNA repair enzymes are associated with the risk of PCa (GPX1 (rs1050450), XRCC1 (rs25487), PON1 (rs662), SOD2 (rs4880), CAT (rs1001179), GSTP1 (rs1695) and CNV GSTM1). A significant increased risk of PCa was found for SOD2 (rs4880) ORGG+GA vs. AA 1.08; 95%CI 1.01-1.15, CAT (rs1001179) ORTT vs. TC+CC 1.39; 95%CI 1.17-1.66, PON1 (rs662) ORCT vs. CC+TT 1.17; 95%CI 1.01-1.35, GSTP1 (rs1695) ORGG vs. GA+AA 1.20; 95%CI 1.05-1.38 and GSTM1 (dual null vs. functional genotype) ORN vs. NN1+NN2 1.34; 95%CI 1.10-1.64. The meta-analysis showed that the CNV GSTM1, and the SNPs GSTP1 (rs1695) and CAT (rs1001179) are strongly associated with a greater risk of PCa and, to a lesser extent, the genetic variants SOD2 (rs4880) and PON1 (rs662). Although several antioxidant enzymes and XME play an important role in the PCa development, other risk factors such as chemical exposures should also be considered to gain insight on PCa risk. The functional in silico analysis showed that the genetic variants studied had no clinical implication regarding malignancy, except for GPX1 (rs1050450) SNP.

The Association Between the Genetic VDR SNP c.907+75C>T and Prostate Cancer Risk Is Modified by Tanning Potential

BACKGROUND

Prostate cancer (PCa) is a multifactorial disease involving complex interactions between genetic and physiological/environmental factors. Vitamin D receptor (VDR) plays a role in numerous cellular pathways and it has been suggested that VDR genetic variants influence individual susceptibility to PCa.

MATERIALS AND METHODS

Logistic regression analysis was used to assess the association of six VDR single nucleotide polymorphisms (SNPs) and factors such as tanning potential and UV sunlight exposure with PCa risk.

RESULTS

Marginal significant interactions were found, with a 2-fold increase risk of PCa between SNP 1 (c.278-69G>A) and sunlight UV exposure [odds ratio (OR)=2.02, 95% confidence intervaI (CI)=1.036-4.36; p=0.05]; and a 4-fold increase risk of PCa between SNP 4 (c.907+75C>T) and tanning potential (OR=4.40, 95% CI=0.89-29.12; p=0.0591). In contrast, SNP 5 (rs731236, TaqI) and tanning potential interaction had a protective effect by reducing the risk of PCa by 55% (β=-0.804; OR=0.448, 95% CI=0.197-9.42; p=0.0427). SNPs 2 (rs61614328) and 6 (rs533037428) did not show any association with PCa even in the presence of UV sunlight exposure.

CONCLUSION

The protective effect of SNP 4 from PCa is lost and modified by tanning potential in African Americans. This finding needs to be verified by larger studies in different ethnic populations.

Intensity modulated radiotherapy in combination with endocrinotherapy in the treatment of middle and advanced Prostatic Cancer

Objective:

To evaluate the clinical efficacy of intensity modulated radiation therapy and endocrinotherapy for middle and advanced prostate cancer.

Methods:

Total 104 elderly patients with middle and advanced prostate cancer who were admitted to our hospital from November 2014 to August 2015 were selected using random number table method. They were divided into intensity-modulated radiotherapy combined with endocrinotherapy group (observation group) and conventional radiotherapy combined with endocrinotherapy group (control group), 52 each. The serum levels of prostate specific antigen (PSA) and free prostate antigen (f PSA) were measured three months after treatment. The short-term efficacy and toxic and side effects of the patients were observed, and the survival rate was recorded through three-year follow up.

Results:

The clinical effective rate of the observation group was 92.68%, and that of the control group was 70.73%; there was a significant difference between the two groups (P<0.05). The serum PSA and f PSA levels of the two groups were similar before treatment, but there was no significant difference (P>0.05). The serum PSA and f PSA levels after treatment were significantly lower than before treatment. The incidence of adverse reactions in the observation group was lower than that in the control group (P<0.05). The one-year and three-year survival rates of the two groups were significantly different (90.0 vs. 80.0%, 60.0 vs. 43.3%, P>0.05).

Conclusion:

Intensity modulated radiotherapy combined with endocrinotherapy was safe and well tolerated in the treatment of middle and advanced prostate cancer. It can improve the short-term efficacy and effectively reduce the serum oncological index concentration of patients. It can be promoted in clinics.

Assessing health risks from multiple environmental stressors: Moving from G×E to I×E

Research on disease causation often attempts to isolate the effects of individual factors, including individual genes or environmental factors. This reductionist approach has generated many discoveries, but misses important interactive and cumulative effects that may help explain the broad range of variability in disease occurrence observed across studies and individuals. A disease rarely results from a single factor, and instead results from a broader combination of factors, characterized here as intrinsic (I) and extrinsic (E) factors. Intrinsic vulnerability or resilience emanates from a variety of both fixed and shifting biological factors including genetic traits, while extrinsic factors comprise all biologically-relevant external stressors encountered across the lifespan. The I×E concept incorporates the multi-factorial and dynamic nature of health and disease and provides a unified, conceptual basis for integrating results from multiple areas of research, including genomics, G×E, developmental origins of health and disease, and the exposome. We describe the utility of the I×E concept to better understand and characterize the cumulative impact of multiple extrinsic and intrinsic factors on individual and population health. New research methods increasingly facilitate the measurement of multifactorial and interactive effects in epidemiological and toxicological studies. Tiered or indicator-based approaches can guide the selection of potentially relevant I and E factors for study and quantification, and exposomics methods may eventually produce results that can be used to generate a response function over the life course. Quantitative data on I×E interactive effects should generate a better understanding of the variability in human response to environmental factors. The proposed I×E concept highlights the role for broader study design in order to identify extrinsic and intrinsic factors amenable to interventions at the individual and population levels in order to enhance resilience, reduce vulnerability and improve health.

Associations of LIM kinase1 (LIMK1) gene single nucleotide polymorphisms with prostate cancer susceptibility in Chinese population

BACKGROUND

Prostate cancer is one of the most common cancers in men. LIM kinase1 (LIMK1) is a mediator in the process of cytoskeleton reorganization and cell motility. LIMK1 is related to progression, invasiveness and metastases of prostate cancer. However, the relationship between LIMK1 single nucleotide polymorphism (SNP) and the risk of prostate cancer has not been studied.

AIM

The aim of our study is to determine the association between LIMK1 polymorphisms and the risk of prostate in a Chinese population.

METHODS

This case-control study consisted of 162 prostate cancer patients and 187 healthy control subjects. Five SNPs of LIMK1 including rs2269082, rs2269081, rs178409, rs6460071 and rs710968 were genotyped using iPLEX genotyping assays on a MassARRAY^® platform.

RESULTS

No significant relationships were found between polymorphisms genotypes and the risk of prostate cancer. Also, no significant associations were found between genotypes and the individual factors such as Gleason Score, alcohol and cigarette consuming statuses.

CONCLUSION

These polymorphisms of LIMK1 were not significantly associated with prostate cancer susceptibility in Chinese men.