Non-dietary environmental risk factors in prostate cancer

The significance of biological, environmental, and social risk factors for prostate cancer in a cohort study in Brazil

PURPOSE

To evaluate the significance of several risk factors for prostate cancer in a cohort of Brazilian men.

SUBJECTS AND METHODS

Men ≥ 40 years-old participating in a prostate cancer screening program between December 2006 and April 2011 in the city of Curitiba, Brazil, were evaluated to determine the prevalence, relative risk (RR) and 95 % CI of prostate cancer according to age, race, ethnicity, family history of prostate cancer, educational level, and history of vasectomy, increased blood pressure, diabetes mellitus, and urethritis.

RESULTS

In 2121 men included in this study, prostate cancer prevalence was 0.6 % for men between 40-49 years versus 2.0 % (adjusted RR = 2.58), 7.7 % (adjusted RR = 5.76), and 8.4 % (adjusted RR = 4.88) for men 50-59 years, 60-69 years, and ≥ 70 years, respectively (p < 0.05 to all). The prevalence of cancer was 5.1% in blacks versus 3.3 % in whites (adjusted RR = 1.56, p > 0.05); 6.1 % in African descendants, in comparison to 3.0 % in non-African descendants (adjusted RR = 3.17, p < 0.05); 5.1% in men with a positive family history, compared to 2.5 % in those with no family history (adjusted RR = 1.55, p > 0.05); and 4.8 % in participants with incomplete elementary school level or lower, compared to 2.2 % in men with complete elementary school level or higher education (adjusted RR = 1.85, p > 0.05). Men with/without history of vasectomy, increased blood pressure, diabetes, and urethritis had a prostate cancer prevalence of 0.8 %/3.0 % (adjusted RR = 0.23, p > 0.05), 3.8 %/2.2 % (adjusted RR = 1.16, p > 0.05), 3.7 %/2.6 % (adjusted RR = 1.39, p > 0.05), and 2.6 %/2.6 % (adjusted RR = 0.99, p > 0.05), respectively.

CONCLUSIONS

Risk factors associated with an increased prevalence of prostate cancer in this cohort included increasing age and African ethnicity.

Steroid 5-alpha-reductase type 2 (SRD5A2) V89L and A49T polymorphisms and sporadic prostate cancer risk: a meta-analysis

Steroid 5-α-reductase type 2 (SRD5A2) V89L and A49T polymorphisms are thought to play a crucial role in the androgen synthesis and metabolic pathway, but their associations with prostate cancer risk remain controversial. To provide a more precise estimation of the associations between V89L and A49T polymorphisms and prostate cancer risk, we performed a meta-analysis using all published case-control studies of prostate cancer since January 1995. We used odds ratio (OR) and its 95% confidence interval (CI) to assess the strength of the association under various genetic models in both overall and stratified analyses. We also calculated the false-positive report probability, the power of the current study, and the observed P value for significant findings. This analysis included 45 eligible studies of a total of 15,562 cases and 15,385 controls, in which no significant associations were found for the V89L polymorphisms under all genetic models. However, small excess prostate cancer risk was associated with the 49T allele in mixed populations compared with the 49A allele (OR = 1.24, 95% CI = 1.02-1.50), and similar results were observed in Caucasians (OR = 1.24, 95% CI = 1.01-1.53). The sensitivity analysis further strengthened the validity of these findings without publication bias. Although there was no overall association between V89L and prostate cancer risk, A49T might play a role in the etiology of prostate cancer among Caucasians. Additional large and well-designed studies are warranted to validate these findings.

Evaluation of xenotropic murine leukemia virus and its R426Q polymorphism in patients with prostate cancer in Kerman, southeast of Iran

A role for the xenotropic murine leukemia virus (XMRV) in prostate cancer development has been postulated. To answer questions regarding the prevalence of XMRV in Iranian patients with prostate cancer and its association with the RNASEL R462Q polymorphism, we here investigated a series of cases in Kerman, in the Southeast of Iran, and sought to verify the association with the R462Q using Real Time PCR Method. Prostate tissue specimens of 200 patients with prostate cancer were genotyped for R462Q by real time polymerase chain reaction allelic discrimination and were screened for XMRV proviral DNA by real time polymerase chain reaction specific for the envelope gene. Of 200 patients in this study 8 (4%) cases were positive for XMRV, the QQ allele being the most frequent regarding the R426Q polymorphism while in negative patients it was the RQ allele. There was significant correlation between high pathological scores and XMRV positive samples. No significant relationship was found between age groups and XMRV results. XMRV was only found in patients with QQ and RQ alleles, not RR. XMRV is detectable in tumor prostate tissue from some patients with prostate cancer, independent of R462Q.