Association between 8q24 Gene Polymorphisms and the Risk of Prostate Cancer: A Systematic Review and Meta-Analysis

CASC11 and PVT1 spliced transcripts play an oncogenic role in colorectal carcinogenesis

Cancer is fundamentally a genetic disorder that alters cellular information flow toward aberrant growth. The coding part accounts for less than 2% of the human genome, and it has become apparent that aberrations within the noncoding genome drive important cancer phenotypes. The numerous carcinogenesis-related genomic variations in the 8q24 region include single nucleotide variations (SNVs), copy number variations (CNVs), and viral integrations occur in the neighboring areas of the MYC locus. It seems that MYC is not the only target of these alterations. The MYC-proximal mutations may act via regulatory noncoding RNAs (ncRNAs). In this study, gene expression analyses indicated that the expression of some PVT1 spliced linear transcripts, CircPVT1, CASC11, and MYC is increased in colorectal cancer (CRC). Moreover, the expression of these genes is associated with some clinicopathological characteristics of CRC. Also, in vitro studies in CRC cell lines demonstrated that CASC11 is mostly detected in the nucleus, and different transcripts of PVT1 have different preferences for nuclear and cytoplasmic parts. Furthermore, perturbation of PVT1 expression and concomitant perturbation in PVT1 and CASC11 expression caused MYC overexpression. It seems that transcription of MYC is under regulatory control at the transcriptional level, i.e., initiation and elongation of transcription by its neighboring genes. Altogether, the current data provide evidence for the notion that these noncoding transcripts can significantly participate in the MYC regulation network and in the carcinogenesis of colorectal cells.

Association between genetic variations at 8q24 and prostate cancer risk in Mexican Men

BACKGROUND

Variants of 8q24 locus have been associated with prostate cancer (PCa) susceptibility. This study aims to analyze the genetic basis of PCa susceptibility in Mexican men by analyzing SNPs in the 8q24 locus for the first time.

METHODS

A case-control study was performed in 875 men recruited from the Mexican Social Security Institute, 326 patients with PCa, and 549 non-PCa patients (88 with benign prostatic hyperplasia BPH and 461 healthy controls). The 8q24 locus SNPs: rs16901979, rs16983267, rs1447295, and rs7837328 were genotyped by allelic discrimination assays using TaqMan probes. Statistical analysis was performed using Epi Info statistical 7.0 and SNPstats softwares.

RESULTS

All genotype frequencies were in Hardy-Weinberg Equilibrium. No differences were observed in genotype distribution between PCa and non-PCa patients for rs6983267. Under different inheritance models, the rs16901979, rs1447295, and rs7837328 SNPs were associated with PCa (OR = 2.8, 1.8, and 1.72, respectively; Pc < 0.001) when comparing PCa patients against controls. This association remains between PCa and BPH patients under different models (OR = 8.5, 2.2, and 1.9, respectively; Pc < 0.001). There were no significant differences in allele and genotype distribution among BPH patients and controls. The combined effect of the alleles CGAA for the SNPs rs16901979, rs6983267, rs1447295, and rs7837328 showed significant differences between PCa patients and controls (OR = 2.9, 95% CI = 1.48-5.83, Pc = 0.008). Four 8q24 variants were not associated with D'Amico score, age at diagnosis, and bone metastases.

CONCLUSIONS

Our study provides the first confirmation that variants rs16901979, rs1447295, and 7837328 at 8q24 locus are associated with PCa susceptibility in Mexican men.

Association study between common variations in some candidate genes and prostate adenocarcinoma predisposition through multi-stage approach in Iranian population

BACKGROUND

Prostate cancer is one of the five common cancers and has the second incidence rate and the third mortality rate in Iranian population. The purpose of this study was to evaluate the association of rs16901979, rs4242382 and rs1447295 on 8q24 locus, rs2735839 (KLK3 gene) and rs721048 (EHBP1 gene) with prostate adenocarcinoma through multi-stage approach to identify the polymorphisms associated with prostate cancer and use them as screening factors. Screening tests can identify people who may have a chance of developing the disease before detection and any symptoms.

METHODS

The case-control study included 103 cases (prostate adenocarcinoma) and 100 controls (benign prostatic hyperplasia). Tetra-primer ARMS-PCR was used to genotyping of each participant. A Multi-stage approach was used for efficient genomic study. In this method, a smaller number of people can be used. Chi-squared, Fisher's exact test and logistic regression were used to investigate the SNPs associated with prostate cancer and Gleason score.

RESULTS

In the first stage (59 men), the frequency of polymorphisms rs16901979, rs4242382, rs1447295, rs2735839 and rs721048 in the prostate adenocarcinoma group was evaluated compared to the control group (P-value < 0.3) in order to select meaningful polymorphisms. There was not any significant difference between genotype frequency rs16901979 (P = 0.671) and rs721048 (P = 0.474) in the case group compared to BPH. Therefore, these polymorphisms were eliminated, and in the second step (144 men), rs4242382, rs2735839 and rs1447295 were evaluated (P-value < 0.05). According to the total population (203 men), there was significant difference between genotype frequency rs4242382 (P = 0.001), rs2735839 (P = 0.000) and rs1447295 (P = 0.005) even after using Bonferroni correction (p = 0.016). The effect of these three polymorphisms on prostate cancer was not modified by age and PSA. There was a significant difference between the allelic frequency of A vs G (rs4242382, rs2735839) at all classes of Gleason score and A vs C (rs1447295) at Gleason score ≥ 8.

CONCLUSIONS

The results of this study for rs2735839, rs4242382 and rs1447295 indicate the association of these polymorphisms with prostate adenocarcinoma predisposition in Iranian population. Exposure effect is homogeneous between different ages and PSA level categories. These three polymorphisms should be studied in a larger population to confirm these results.