Genetic variants of chemokine CCL2 and chemokine receptor CCR2 genes and risk of prostate cancer

Raju K. Mandal, Toshi Agrawal, Rama Devi Mittal

Chemokines and their receptors acts as mediators of migration of immune cells to the site of inflammation and deregulated inflammatory response is associated with increased risk of cancer. We performed a case-control study to analyze the frequencies of CCL2 (I/D, rs3917887), -2518 (A > G, rs1024611), and CCR2 (G > A, rs1799864) polymorphisms for prostate cancer (PCa) risk. In this hospital-based case-control study, histologically confirmed 195 PCa patients and 250 unrelated healthy controls of similar ethnicity were genotyped by PCR-RFLP. The result showed that heterozygous ID (odds ratio (OR) = 1.71; p = 0.010) carrier genotype of CCL2 gene were at increased risk for developing PCa. Variant allele D carriers (ID + DD) demonstrated a 1.67-fold increased risk (OR = 1.67; p = 0.010), suggesting a dominant effect model involved in PCa risk. Similarly, variant allele D of CCL2 gene also had a higher risk (OR = 1.53; p = 0.040) for developing PCa. High risk to PCa was also observed with respect to diplotypes, I-G (OR = 1.83; Bonferroni corrected p value (P c) = 0.004) and D-A (OR = 2.11; P c = 0.004) of CCL2 I/D and -2518 (A > G). In association of genotypes with clinic-pathological grade of tumor, homozygous DD (OR = 7.40; P c = 0.042) and variant allele carrier ID + DD (OR = 2.42; P c = 0.036) genotypes of CCL2 gene conferred risk in high Gleason grade tumor of PCa. We observed a significantly enhanced risk for PCa due to interaction between CCL2 I/D, -2518 (A > G), and CCR2 (G > A) genotypes. However, -2518 (A > G) and CCR2 V64I (G > A) gene polymorphisms were not significantly associated with PCa risk. Our results supported that CCL2 I/D gene variant contribute to the susceptibility and clinic-pathological characteristic of PCa and could be considered as an important risk factor for this malignancy in North Indian men.