Is there an inter-relationship between prostate specific antigen, kallikrein-2 and androgen receptor gene polymorphisms with risk of prostate cancer in north Indian population?

Association between polymorphic CAG repeat lengths in the androgen receptor gene and susceptibility to prostate cancer: A systematic review and meta-analysis

BACKGROUND

Previous studies have been conducted to reveal the relationship between androgen receptor CAG polymorphism and risk of prostate cancer, yet the results were elusive and controversial. Thus, this meta-analysis was performed to clarify this association.

METHODS

To obtain the relevant available studies, online databases PubMed, Embase, and Web of science were searched until September 1st, 2016. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of such association. Subgroup analyses were conducted based on ethnicity and source of controls. Moreover, Begg's funnel plots and Egger's linear regression test were conducted to test the publication bias.

RESULTS

Overall, our results enrolled 51 studies indicated that significant increased risk of prostate cancer was associated with androgen receptor CAG polymorphism (OR  =  0.77, 95% CI: 0.67-0.89). In addition, compared with CAG repeat <20, 22, carriers of ≧20, 22 repeats had decreased risk of prostate cancer (cut-off point  =  20: OR  =  0.27, 95% CI: 0.13-0.52; cut-off point  =  22: OR  =  0.82, 95% CI: 0.70-0.97). However, when cut-off point  =  23, no significant result was detected in such association (pooled OR  =  0.88, 95% CI: 0.63-1.24). When cut-off point is 22, the results were positive only in Asian population (OR  =  0.53, 95% CI: 0.32-0.89) in the subgroup analysis by ethnicity. Besides, when the studies were stratified by source of controls, the results were not significant in both the subgroup of population-based controls and hospital-based controls.

CONCLUSIONS

This meta-analysis suggested the carriers of short polymorphic CAG repeats might increase susceptibility to prostate cancer, which held potential as a detecting marker of the risk of prostate cancer.

Androgen receptor gene polymorphisms and risk of prostate cancer: a meta-analysis

Although the association between CAG and GGN repeats in the androgen receptor gene and prostate cancer risk has been widely studied, it remains controversial from previous meta-analyses and narrative reviews. Therefore, we performed this meta-analysis to provide more precise estimates with sufficient power. A total of 51 publications with 61 studies for CAG repeats and 14 publications with 16 studies for GGN repeats were identified in the meta-analysis. The results showed that short CAG repeats (<22 repeats) carriers presented an elevated risk of prostate cancer than long CAG repeats (≥22) carriers (OR = 1.31, 95% CI 1.16 to 1.47). Prostate cancer cases presented an average fewer CAG repeats (MD = −0.85, 95% CI −1.28 to −0.42) than controls. Short GGN repeats (≤16) carriers presented an increased risk of prostate cancer than long GGN repeats (>16) carriers (OR = 1.38, 95% CI 1.05 to 1.82). In subgroup analyses, the abovementioned significant association was predominantly observed in Caucasian populations. The meta-analysis showed that short CAG and GGN repeats in androgen receptor gene were associated with increased risk of prostate cancer, especially in Caucasians.

Pulsed dye laser therapy for infantile hemangiomas: a systemic review and meta-analysis

BACKGROUND

Infantile hemangiomas (IH) are common pediatric tumors. This meta-analysis was performed to review the therapeutic efficacy and safety of pulsed dye laser (PDL) in the treatment of IH.

METHODS

Seven databases were searched, including PubMed, OvidSP, Karger, Elsevier, EMBASE, Web of Science and Wiley Online Library. The review collected the characteristics of year of publication, hemangiomas cases, prior treatment, laser parameters, adverse side, pretreatment symptom, and number of response from all articles.

RESULTS

A total of 1580 studies were identified, the first round search retrieved 39 articles met inclusion criteria. Of those, only 13 articles with 1529 hemangiomas were included in the meta-analysis. This meta-analysis demonstrated an overall resolution rate of 89.1% with 6.28% incidence of adverse effect.

CONCLUSION

PDL may be the effective modality to decrease the proliferative phase and accelerate rates of involution and resolution with few adverse events.

Genetic variation in KLK2 and KLK3 is associated with concentrations of hK2 and PSA in serum and seminal plasma in young men

BACKGROUND

Genetic variants in KLK2 and KLK3 have been associated with increased serum concentrations of their encoded proteins, human kallikrein-related peptidase 2 (hK2) and prostate-specific antigen (PSA), and with prostate cancer in older men. Low PSA concentrations in seminal plasma (SP) have been associated with low sperm motility. To evaluate whether KLK2 and KLK3 genetic variants affect physiological prostatic secretion, we studied the association of SNPs with hK2 and PSA concentrations in SP and serum of young, healthy men.

METHODS

Leukocyte DNA was extracted from 303 male military conscripts (median age 18.1 years). Nine SNPs across KLK2-KLK3 were genotyped. We measured PSA and hK2 in SP and serum using immunofluorometric assays. The association of genotype frequencies with hK2 and PSA concentrations was tested with the Kruskal-Wallis test.

RESULTS

Four KLK2 SNPs (rs198972, rs198977, rs198978, and rs80050017) were strongly associated with hK2 concentrations in SP and serum, with individuals homozygous for the major alleles having 3- to 7-fold higher concentrations than the intermediate concentrations found in other homozygotes and heterozygotes (all P < 0.001). Three of these SNPs were significantly associated with percentage of free PSA (%fPSA) in serum (all P < 0.007). Three KLK3 SNPs showed associations with PSA in SP, and the rs1058205 SNP was associated with total PSA in serum (P = 0.001) and %fPSA (P = 0.015).

CONCLUSIONS

Associations observed in young, healthy men between the SP and serum concentrations of hK2 and PSA and several genetic variants in KLK2 and KLK3 could be useful to refine models of PSA cutoff values in prostate cancer testing.

Association of Polymorphism rs198977 in Human Kallikrein-2 Gene (KLK2) with Susceptibility of Prostate Cancer: A Meta-Analysis

OBJECTIVES

To assess the association of polymorphism rs198977 in the human kallikrein-2 gene (KLK2) and risk of prostate cancer (PCa).

METHODS

Two investigators independently searched the PubMed, Elsevier, EMBASE, Web of Science, Wiley Online Library and Chinese National Knowledge Infrastructure (CNKI). Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for rs198977 and PCa were calculated in a fixed-effects model (the Mantel-Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate.

RESULTS

Six studies met the inclusion criteria in this meta-analysis, which included 5859 PCa cases and 4867 controls. Overall, rs198977 was associated with the PCa risk (TT+CT vs. CC, pooled OR = 1.163, 95% CI = 1.076-1.258, P-value <0.0001). When stratified by ethnicity, significant association was observed in Caucasian samples under both allele comparison (T vs. C, pooled OR = 1.152, 95% CI = 1.079-1.229, P-value <0.0001) and dominant model (TT+CT vs. CC, pooled OR = 1.197, 95% CI = 1.104-1.297, P-value <0.0001). In the overall analysis, a comparably significant increase in the frequency of allele T for rs198977 was detected between cases and controls in Caucasian.

CONCLUSION

This meta-analysis suggests that rs198977 of KLK2 was associated with susceptibility of PCa in Caucasian and the allele T might increase the risk of PCa in Caucasian.

Polymorphisms in androgen signaling pathway predisposing to prostate cancer

Prostate cancer is the most frequent male malignancy diagnosed in western countries and androgens are known to mediate key physiological processes in prostate tissue. Since endogenous androgens have long been considered to be risk factors for prostate cancer, genes involved in androgen biosynthesis and metabolism have been extensively studied. In this review, association of androgen pathway genes, their polymorphic sites and risk of prostate cancer in different ethnic backgrounds is addressed together with their use to predict susceptibility and clinical outcomes of prostate cancer patients. The effect of the polymorphisms seems vary in different patients, populations and ethnic backgrounds. To date it is evident that the association between androgen pathway gene polymorphisms and prostate cancer risk is complex and many of the results are characterized by irreproducibility, which can be attributed to a variety of biological, statistical and technical reasons. In the future, with increasing knowledge, developing technologies and new genomic biomarkers it likely becomes possible to better estimate the risk of prostate cancer, and distinguish indolent disease from aggressive based on molecular profiling, and the analysis of gene-gene and gene-environment interactions.

Association of androgen receptor, prostate-specific antigen, and CYP19 gene polymorphisms with prostate carcinoma and benign prostatic hyperplasia in a north Indian population

The genes involved in androgen pathway and metabolism have been reported to contribute considerably to prostate carcinoma (CaP) risk. The present study investigated the association of androgen receptor (AR), prostate-specific antigen (PSA or KLK3), and cytochrome P450 (CYP19) gene polymorphisms in CaP (n=105) and benign prostatic hyperplasia (BPH) (n=120) in comparison to normal healthy controls (n=106) in an Indian population. We also evaluated the functional consequences of these gene variants on AR and PSA mRNA expression. Significant association of short AR CAG repeats (≤24) with risk of CaP (odds ratios [OR]=2.98, p<0.001) and BPH (OR=1.96, p=0.01) was observed; however, CYP19 gene polymorphism was not found to be associated with disease phenotype (p>0.05). PSA G-158A SNP was found to be significantly associated with risk of CaP (AA: OR=2.68, p=0.016 and GA: OR=2.07, p=0.018) p-trend 0.031 and BPH (AA: OR=3.46, p<0.001 and GA: OR=2.47, p=0.03) p-trend 0.009, respectively. PSA G-158A genotype independently increased the risk of developing BPH (OR=16.37, p<0.001), irrespective of AR CAG repeat length. Using quantitative real-time polymerase chain reaction, we found a significant upregulation of AR and PSA mRNA expression in CaP comparison to BPH. While short AR CAG (≤24) repeats were associated with higher AR mRNA expression in CaP (p=0.002), the PSA SNP did not correlate with its mRNA expression. Interestingly, significantly higher risk estimates for CaP were observed for the combined analysis of short AR CAG and CYP19 genotypes (A2A2) (OR=7.18, p<0.001) or A2A3 (OR=7.60, p=0.004). Our results suggest significant association of androgen signaling gene polymorphisms with risk of CaP and BPH and provide evidence for a putative functional role of AR CAG repeat in regulating its mRNA expression and warrant the need of larger studies in the Indian population to confirm our results.

Relationship of obesity, androgen receptor genotypes and biochemical failure after radical prostatectomy

BACKGROUND

Obesity and androgen metabolism have been implicated in the progression of prostate cancer. Obesity has been associated with increased risk for advanced disease and biochemical failure after treatment. This association may be the result of changes in androgen metabolism that occur with obesity and are mediated by the androgen receptor (AR).

METHODS

To evaluate the effects of obesity and AR polymorphisms on biochemical failure, we conducted a study of 536 Caucasian prostate cancer cases. We determined the relationship between time to biochemical failure and obesity stratified by short and long AR-CAG and AR-GGN repeat sequence. The AR repeat groups were dichotomized at the median number of repeats for each polymorphism.

RESULTS

An association was found for obesity in the short CAG group (HR = 3.45, 95% CI = 1.00-11.96). Among obese patients diagnosed with localized disease (T1/T2), the risk of biochemical failure was significantly higher (HR = 7.05, 95% CI = 1.55-32.06). No difference was observed for high stage (T3/T4) obese patients. Additionally, no differences in biochemical failure were observed in obese and non-obese men grouped by number of AR-GGN repeats.

CONCLUSIONS

Obesity is significantly associated with increased risk of biochemical failure in men with the high-risk short CAG sequence on the AR gene. This effect is not observed in men with long CAG repeats. Therefore, it appears that the relationship between biochemical failure and obesity may be modified by the AR-CAG repeat pattern. The short AR-CAG genotype may be more responsive to an altered hormonal milieu created by obesity.

The CAG repeat polymorphism of androgen receptor gene and prostate cancer: a meta-analysis

The association between the polymorphic CAG repeat in androgen receptor gene (AR) and prostate cancer susceptibility has been studied extensively. However, the results are contradictory. The purpose of our meta-analysis was to investigate whether CAG repeat related to prostate cancer risk and had genetic heterogeneity across different geographic regions and study designs. Random-effects model was performed irrespective of between-study heterogeneity. Data and study quality were assessed in duplicate. Publication bias was assessed by the fail-safe number and Egger's test. There were 16 (patients/controls: 2972/3792), 19 (3835/4908) and 12 (3372/2631) study groups for comparisons of ≥ 20, 22 and 23 repeats of CAG sequence, respectively. Compared with CAG repeat <20, 22 or 23, carriers of ≥ 20, 22 or 23 repeats had 21% (95% CI: 0.61-1.02; P = 0.076), 5% (95% CI: 0.81-1.11; P = 0.508) and 5% (95% CI: 0.76-1.20; P = 0.681) decreased risk of prostate cancer. After classifying studies by geographic areas, carriers of ≥ 20 repeats had 11% decreased risk in populations from USA, 53% from Europe, and 20% from Asia (P > 0.05), whereas comparison of ≥ 23 repeats with others generated a significant prediction in European populations (OR = 1.17; P = 0.039). Stratification by study designs revealed no material changes in risk estimation. Meta-regression analysis found no significant sources of between-study heterogeneity for age, study design and geographic region for all comparisons. There was no identified publication bias. Taken together, our results demonstrated that AR CAG repeat polymorphism with ≥ 20 repeats might confer a protective effect among the prostate cancer patients with 45 years older but not all the prostate cancer patients.

Prostate-specific antigen and 17-hydroxylase polymorphic genotypes in patients with prostate cancer and benign prostatic hyperplasia

We investigated the association of prostate cancer (PCa) and benign prostatic hyperplasia (BPH) with genetic polymorphisms in prostate-specific antigen (PSA) (-158 G/A) and 17-hydroxylase (CYP17) (-34 T/C) genes in a Turkish population. In this study, we investigated the distribution of these polymorphisms in 148 PCa patients, 136 BPH patients, and 102 healthy individuals as controls. The polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism assay. Genotype and allele frequencies were calculated, and their associations with PCa or BPH risk are assayed. The frequency of PSA gene GA and GG genotypes was significantly higher in PCa patients than in controls (p = 0.017 and p = 0.019, respectively). GG genotype was also associated with BPH (p = 0.033). In a case analysis, according to Gleason score, the association of PSA gene GG genotype with Gleason score >7 was near to statistical significance (odds ratio, 2.94; 95% confidence interval, 0.95-9.28). There was also an association between CYP17 polymorphism and BPH (p = 0.004). No association was observed between PCa and CYP17 gene polymorphism. These data demonstrate that PSA gene promoter variation may play a significant role in the development of PCa and BPH, and that CYP17 gene polymorphism may be associated with BPH in the Turkish population studied.