Yifeng Zhou

A non-synonymous polymorphism Thr115Met in the EpCAM gene is associated with an increased risk of breast cancer in Chinese population

As a tumor-associated antigen and a surface marker of breast cancer stem cells (BCSCs), epithelial cell adhesion molecule (EpCAM) plays an important role in not only cell adhesion, morphogenesis, metastases but also carcinogenesis. A non-synonymous C/T polymorphism (rs1126497) in exon3 of EpCAM causes a transition of 115 amino acid from Met to Thr. Another polymorphism (A/G, rs1421) in the 3′UTR causes loss of has-miR-1183 binding. A multiple independent case–control analysis was performed to assess the association between EpCAM genotypes and breast cancer risk. We observed that the variant EpCAM genotype (rs1126497 CT, and TT) was associated with substantially increased risk of breast cancer. Genotyping a total of 1643 individuals with breast cancer and 1818 control subjects in Eastern and Southern Chinese populations showed that rs1126497 CTxa0+xa0TT genotype had an odd ratio of 1.40 (95% confidence interval, 1.16–1.57) for developing breast cancer compared with CC genotype. The allele T increases the risk of breast cancer in a dose-dependent response manner (Ptrendxa0<xa00.001). Moreover, compared to breast cancer patients carrying the CC genotype, the EpCAM SNP rs1126497 CT or TT carrier was significantly associated with early breast cancer onset (Pxa0=xa00.0023). However, no significant difference was found in genotype frequencies at the rs1421 A/G site between cases and controls. These findings suggest that M115T polymorphism in EpCAM may be a genetic modifier for developing breast cancer.

CD44 rs13347 C>T polymorphism predicts breast cancer risk and prognosis in Chinese populations.

IntroductionIt has been demonstrated that the interplay of adhesion molecule CD44 and its ligands can regulate cancer cell proliferation, migration and invasion, as well as tumor-associated angiogenesis and is related to breast cancer patient survival. In this two-stage, case control study, we determined whether common functional tagSNPs (single nucleotide polymorphisms) are associated with breast cancer risk and prognosis.MethodsFive tagSNPs of CD44 (rs10836347C>T, rs13347C>T, rs1425802A>G, rs11821102G>A, rs713330T>C) were selected and genotyped in 1,853 breast cancer patients and 1,992 healthy control subjects in Eastern and Southern populations. Potential function of rs13347C>T and association between this variation and breast cancer were further studied.ResultsCompared with the most common rs13347CC genotype, variant genotypes (CT and TT) increased an individuals susceptibility to breast cancer, especially in estrogen receptor (ER) negative patients (odds ratio (OR) = 1.37, 95%CI = 1.17 to 1.59 for ER positive patients; OR = 2.37, 95% CI = 2.00 to 2.80 for ER negative patients). We also found that rs13347CT+ TT genotypes predicts lower five-year survival rate (hazard ratio (HR) = 1.85, 95% CI = 1.09 to 3.15, P = 0.023), with the lowest survival probability in ER negative T allele carriers. Furthermore, our reporter assay findings, although preliminary and rather modest, showed that miR-509-3p may suppress CD44 expression more strongly in C allele carriers than T allele carriers (P < 0.01). Similarly, rs13347 variant genotypes (CT and TT) carriers were shown to have more CD44 expression than CC carriers in both immunohistochemistry (P < 0.001) and western blotting (P = 0.001) results.ConclusionThese findings suggest that CD44 rs13347C>T polymorphism may affect breast cancer development and prognosis by increasing CD44 expression.

A Sequence Polymorphism in miR-608 Predicts Recurrence after Radiotherapy for Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma is treated with radiotherapy and other modalities, but there is little information on individual genetic factors to help predict and improve patient outcomes. Single-nucleotide polymorphisms (SNP) in mature microRNA (miRNA) sequences have the potential to exert broad impact as miRNAs target many mRNAs. The aim of this study was to evaluate the effects of SNPs in mature miRNA sequences on clinical outcome in patients with nasopharyngeal carcinoma receiving radiotherapy. In particular, we analyzed associations between seven SNPs and nasopharyngeal carcinoma locoregional recurrence (LRR) in 837 patients from eastern China, validating the findings in an additional 828 patients from southern China. We found that miR-608 rs4919510C > G exhibited a consistent association with LRR in the discovery set [HR, 2.05; 95% confidence interval (CI), 1.35-3.21], the validation set (HR, 2.24; 95% CI, 1.45-3.38), and the combined dataset (HR, 2.08; 95% CI, 1.41-3.26). Biochemical investigations showed that rs4919510C > G affects expression of miR-608 target genes along with nasopharyngeal carcinoma cell growth after irradiation in vivo and in vitro. Notably, X-ray radiation induced more chromatid breaks in lymphocyte cells from rs4919510CC carriers than in those from subjects with other genotypes (P = 0.0024). Our findings reveal rs4919510C > G in miR-608 as a simple marker to predict LRR in patients with radiotherapy-treated nasopharyngeal carcinoma.

Functional polymorphisms in NFκB1/IκBα predict risks of chronic obstructive pulmonary disease and lung cancer in Chinese

Lung inflammation is the major pathogenetic feature for both chronic obstructive pulmonary disease (COPD) and lung cancer. The nuclear factor-kappa B (NFκB) and its inhibitor (IκB) play crucial roles in inflammatory. Here, we tested the hypothesis that single nucleotide polymorphisms (SNPs) in NFκB/IκB confer consistent risks for COPD and lung cancer. Four putative functional SNPs (NFκB1: −94del>insATTG; NFκB2: −2966G>A; IκBα: −826C>T, 2758G>A) were analyzed in southern and validated in eastern Chineses to test their associations with COPD risk in 1,511 COPD patients and 1,677 normal lung function controls, as well as lung cancer risk in 1,559 lung cancer cases and 1,679 cancer-free controls. We found that the −94ins ATTG variants (ins/delxa0+xa0ins/ins) in NFκB1 conferred an increased risk of COPD (OR 1.27, 95xa0% CI 1.06–1.52) and promoted COPD progression by accelerating annual FEV1 decline (Pxa0=xa00.015). The 2758AA variant in IκBα had an increased risk of lung cancer (OR 1.53, 95xa0% CI 1.30–1.80) by decreasing IκBα expression due to the modulation of microRNA hsa-miR-449a but not hsa-miR-34b. Furthermore, both adverse genotypes exerted effect on increasing lung cancer risk in individuals with pre-existing COPD, while the −94del>insATTG did not in those without pre-existing COPD. However, no significant association with COPD or lung cancer was observed for −2966G>A and −826C>T. Our data suggested a common susceptible mechanism of inflammation in lung induced by genetic variants in NFκB1 (−94del>ins ATTG) or IκBα (2758G>A) to predict risk of COPD or lung cancer.

Polymorphism in mature microRNA-608 sequence is associated with an increased risk of nasopharyngeal carcinoma

Accumulative evidences indicated that microRNAs (miRNAs) can function as tumor suppressors and oncogenes, in which genetic variations are implicated in various cancer susceptibilities. However, it remains unclear whether single nucleotide polymorphisms (SNPs) in mature miRNA sequence alter nasopharyngeal carcinoma (NPC) susceptibility. In this study, we analyzed associations between eight SNPs in miRNA mature sequences (i.e., rs3746444T>C in hsa-mir-499, rs4919510C>G in hsa-mir-608, rs13299349G>A in hsa-mir-3152, rs12220909G>C in hsa-mir-4293, rs2168518G>A in hsa-mir-4513, rs8078913T>C in hsa-mir-4520a, rs11237828T>C in hsa-mir-5579, and rs9295535T>C in hsa-mir-5689) and NPC susceptibility in southern China with 906 NPC cases and 1072 cancer-free controls, and validated the significant findings in eastern China with 684 cases and 907 healthy controls. Functional assays were further performed to identify the biological effects of these polymorphisms. We found that rs4919510C>G polymorphism showed a consistent association with NPC risk in southern China (GC+GG versus CC genotype, odds ratio [OR]=1.36, 95% confidence interval [CI]=1.10-1.70) and eastern China (GC+GG versus CC: OR=1.37, 95% CI=1.08-1.74). After the two populations were merged, the ORs and 95% CI were 1.38 and 1.18 to 1.62, respectively. Moreover, the rs4919510C>G adverse genotypes significantly interacted with Epstein-Barr virus (EBV) infection on increasing NPC risk (P=0.001). The functional assay further showed that the CNE-2 cell lines that transfected with miR-608-rs4919510G allele expression vector exerted more colony number formations than cell lines that transfected with miR-608-rs4919510C allele expression vector (P=0.001). These data suggested that rs4919510C>G of miR-608 may be a susceptible biomarker of NPC in China.

Heterozygous Genetic Variations of FOXP3 in Xp11.23 Elevate Breast Cancer Risk in Chinese Population via Skewed X-Chromosome Inactivation

FOXP3 (forkhead box P3: also known as IPEX, XPID) is not only a hallmark of immunosuppressive regulatory T cells (Tregs), but also an X‐linked breast cancer suppressor gene expressed in tumor cells. A two‐stage investigation was conducted in individuals from northern, southern and eastern China. Individuals carrying a FOXP3 rs2294021CT genotype showed about 1.5‐fold increased risk of breast cancer compared with TT carriers. In a related biochemical assay, the rs2294021C allele was found to significantly enhance transcription activity, leading to higher mRNA levels of FOXP3 compared with T allele. Moreover, the number of Tregs and its corresponding interleukin‐10 (IL‐10) secretion were elevated whereas the proliferation of antitumor T cells was decreased in the C‐allele carriers. The breast cancer oncogenes Her‐2/ErbB2 and Skp2 were also found to be significantly inhibited in C‐allele carriers. Moreover, skewed X‐chromosome inactivation (SXCI) analysis showed that rs2294021CT carriers with SXCI showed higher risk than the homozygous carriers and CT carriers without SXCI, suggesting a possible interaction between the rs2294021CT genotype and SXCI. Taken together, these findings indicate that the rs2294021CT genotype may increase an individuals susceptibility to breast cancer by breaking the balance between Treg‐mediated immune tolerance and FOXP3‐controlled tumor‐suppressive effect.

IL-21 gene polymorphism is associated with the prognosis of breast cancer in Chinese populations

Interleukin (IL)-21, which is secreted by activated CD4+ T cells and NKT cells, has been found to be able to influence the humoral and cell-mediated immune responses and have potent antitumor activity in animal models. This study was to investigate the impact of genetic polymorphisms in IL-21 on survival of breast cancer. Four TagSNPs of IL-21 (rs12508721C>T, rs907715G>A, rs13143866G>A, rs2221903A>G) were selected and then genotyped in 891 patients with breast cancer in Eastern and Southern Chinese populations. We then examined the associations between these SNPs and overall survival. Potential function of rs12508721C>T and association between this variation and breast cancer prognosis were further studied. Overall, 121 of the patients had died over the followed-up period of 5xa0years. The IL-21 rs12508721T allele predicted longer five-year survival (HRxa0=xa00.347, 95xa0% CIxa0=xa00.187–0.644, Pxa0<xa00.0001) in the discovery cohort, the independent validation cohort (HRxa0=xa00.429, 95xa0% CIxa0=xa00.244–0.755, Pxa0=xa00.012), and combined group (HRxa0=xa00.447, 95xa0% CIxa0=xa00.301–0.667, Pxa0<xa00.0001). Furthermore, our luciferase assay revealed that rs12508721T variant allele had a higher transcription activity and the RT-PCR and ELISA assay showed that rs12508721 variant genotypes (CT and TT) carriers have more IL-21 expression than CC carriers (Pxa0<xa00.05). Our present study established a robust association between the functional polymorphism (rs12508721C>T) in IL-21 and prognosis of breast cancer, indicating that this polymorphism may be a potential biomarker for prognosis of breast cancer.

Functional polymorphisms in PIN1 promoter and esophageal carcinoma susceptibility in Chinese population.

Peptidyl-prolyl cis–trans isomerase NIMA-interacting 1 (PIN1), which regulates the conformation of Pro-directed phosphorylation sites, has been identified as a critical catalyst involved in multiple oncogenic signaling pathways. Recently, it has been demonstrated that several putative functional polymorphisms of PIN1 gene were associated with cancer risk. This study examined whether genetic polymorphisms in promoter of PIN1 are associated with esophageal carcinoma susceptibility. Two common polymorphisms in PIN1, rs2233678 (−842G>C) and rs2233679 (−667C>T) were genotyped in this hospital-based case–control study of 699 esophageal carcinoma patients and 729 healthy controls. The results revealed that compared with the most common −842GG genotype carriers, the carriers of −842C variant genotypes (GC+CC) had significantly decreased risk of esophageal carcinoma [odds ratio (OR)xa0=xa00.55, 95xa0% CIxa0=xa0(0.40–0.75), Pxa0=xa00.001]. No association was observed between the −667C>T polymorphism and the risk of esophageal carcinoma. Furthermore, we found that the haplotype of ‘C−842–C−667’ had a greater protected effect [ORxa0=xa00.67, 95xa0% CIxa0=xa0(0.47–0.96), Pxa0=xa00.021]. Functional assay revealed that −842C variant genotypes (GC+CC) carriers had a lower transcription activity and mRNA expression level than the −842GG carriers. These results indicated that −842G>C genetic variant in PIN1 promoter may decrease the promoter activity, resulting in changes in the levels of PIN1 and modifying cancer susceptibility.

NBS1 rs1805794G>C polymorphism is associated with decreased risk of acute myeloid leukemia in a Chinese population

As a key encoding protein gene of MRN (MRE11-RAD50-NBS1) complex, NBS1 plays a crucial role in maintaining genomic stability and preventing cell apoptosis, inflammation and tumorgenesis. Single nucleotide polymorphisms (rs2735383 and rs1805794) in NBS1 have been frequently studied in some cancers with discordant results in previous case–control studies. However, the relationship between these two functional polymorphisms and the susceptibility to acute myeloid leukemia (AML) in Chinese population has not been investigated. We performed a case–control study with 428 patients and 600 controls to detect the association between the two polymorphisms of NBS1 and the risk of AML in a Chinese population. The polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method was carried out to determine the genotypes of potential functional SNPs in NBS1 gene. The results showed that compared with the homozygous carriers rs1805794CC, rs1805794GC genotype was significantly associated with decreased risk of AML in total subjects (adjusted odds ratio (OR)xa0=xa00.50; 95xa0% CIxa0=xa00.37–0.67), the risk decreased even further in those carrying rs1805794GG genotype (ORxa0=xa00.23; 95xa0% CIxa0=xa00.16–0.34). No significant association was found between rs2735383C>G polymorphism and the risk of AML (ORxa0=xa00.93; 95xa0% CIxa0=xa00.71–1.22 for GC; ORxa0=xa00.78; 95xa0% CIxa0=xa00.53–1.13 for CC, Pxa0=xa00.152). These findings indicated that rs1805794G/C polymorphism in NBS1 may play a protective role in mediating the risk of AML.

Duplicated copy of CHRNA7 increases risk and worsens prognosis of COPD and lung cancer

Recent genome-wide association studies implicated that the nicotinic acetylcholine receptors (nAChRs) are common susceptible genes of two contextual diseases: chronic obstructive pulmonary disease (COPD) and lung cancer. We aimed to test whether the copy number variations (CNVs) in nAChRs have hereditary contributions to development of the two diseases. In two, two-stage, case–control studies of southern and eastern Chinese, a common CNV-3956 that duplicates the cholinergic receptor, nicotinic, α7 (CHRNA7) gene was genotyped in a total of 7880 subjects and its biological phenotype was assessed. The ≥4-copy of CNV-3956 increased COPD risk (≥4-copy vs 2/3-copy: OR=1.44, 95% CI=1.23–1.68) and caused poor lung function, and it similarly augmented risk (OR=1.49, 95% CI=1.29–1.73) and worsened prognosis (hazard ratio (HR)=1.25, 95% CI=1.07–1.45) of lung cancer. The ≥4-copy was estimated to account for 1.56% of COPD heritability and 1.87% of lung cancer heritability, respectively. Phenotypic analysis further showed that the ≥4-copy of CNV-3956 improved CHRNA7 expression in vivo and increased the carriers’ smoking amount. The CNV-3956 of CHRNA7 contributed to increased risks and poor prognoses of both COPD and lung cancer, and this may be a genetic biomarker of the two diseases.