Association between GPC2 polymorphisms and neuroblastoma risk in Chinese children

Functional TET2 gene polymorphisms increase the risk of neuroblastoma in Chinese children

The 5-methylcytosine (m5C) is the key chemical modification in RNAs. As one of the demethylases in m5C, TET2 has been shown as a tumor suppressor. However, the impact of TET2 gene polymorphisms on neuroblastoma has not been elucidated. 402 neuroblastoma patients and 473 controls were genotyped for TET2 gene polymorphisms using the TaqMan method. The impact of TET2 gene polymorphisms on neuroblastoma susceptibility was determined using multivariate logistic regression analysis. We also adopted genotype-tissue expression database to explore the impact of TET2 gene polymorphisms on the expression of host and nearby genes. We used the R2 platform and Sangerbox tool to analyze the relationship between gene expression and neuroblastoma risk and prognosis through non-parametric testing and Kaplan-Meier analysis, respectively. We found the TET2 gene polymorphisms (rs10007915 G > C and rs7670522 A > C) and the combined 2-5 risk genotypes can significantly increase neuroblastoma risk. Stratification analysis showed that these significant associations were more prominent in certain subgroups. TET2 rs10007915 G > C and rs7670522 A > C are significantly associated with reduced expression of TET2 mRNA. Moreover, lower expression of TET2 gene is associated with high risk, MYCN amplification, and poor prognosis of neuroblastoma. The rs10007915 G > C and rs7670522 A > C are significantly related to the increased expression of inorganic pyrophosphatase 2 mRNA, and higher expression of PPA2 gene is associated with high risk, MYCN amplification, and poor prognosis of neuroblastomas. In summary, TET2 rs10007915 G > C and rs7670522 A > C significantly confer neuroblastoma susceptibility, and further research is needed to investigate the underlying mechanisms.

ALKBH5 gene polymorphisms and risk of neuroblastoma in Chinese children from Jiangsu Province

Background

Neuroblastoma is one of the most common extracranial malignant solid tumors in children. AlkB homolog 5 (ALKBH5) is an RNA N6-methyladenosine (m6A) demethylase that plays a critical role in tumorigenesis and development. We assessed the association between single nucleotide polymorphisms (SNPs) in ALKBH5 and the risk of neuroblastoma in a case-control study including 402 patients and 473 non-cancer controls.

Methods

Genotyping was determined by the TaqMan method. The association between ALKBH5 polymorphisms (rs1378602 and rs8400) and the risk of neuroblastoma was evaluated using the odds ratio (OR) and 95% confidence interval (CI).

Results

We found no strong association of ALKBH5 rs1378602 and rs8400 with neuroblastoma risk. Further stratification analysis by age, sex, primary site, and clinical stage showed that the rs1378602 AG/AA genotype was associated with a lower risk of neuroblastoma in males (adjusted OR = 0.58, 95% CI = 0.35-0.97, p = 0.036) and children with retroperitoneal neuroblastoma (adjusted OR = 0.58, 95% CI = 0.34-0.98, p = 0.040).

Conclusions

ALKBH5 SNPs do not seem to be associated with neuroblastoma risk. More studies are required to confirm this negative result and reveal the relationship between gene polymorphisms of the m6A modifier ALKBH5 and neuroblastoma.

ALKBH1 rs2267755 C>T polymorphism decreases neuroblastoma risk in Chinese children

Neuroblastoma is a highly malignant extracranial solid tumor in pediatrics. ALKBH1 as a recently discovered DNA N6-methyldeoxyadenosine (6mA) demethylase closely links to tumorigenesis. Whether the ALKBH1 polymorphism contributes to neuroblastoma risk remains unclear. In the present study, we genotyped the ALKBH1 single nucleotide polymorphisms (SNPs) in 402 neuroblastoma patients and 473 healthy controls by TaqMan assay. Odds ratios (ORs) and 95% confidence intervals (CIs) were also calculated to evaluate the strength of the association. Our result exhibited that the rs2267755 C>T (CT vs. CC, adjusted OR=0.69, 95% CI=0.50-0.94, P=0.019) is significantly associated with reduced neuroblastoma risk. And its protective effect is particularly significant in children with tumors originating from the retroperitoneal. Combined genotype analysis revealed that carriers with 1-2 protective genotypes are more susceptible to neuroblastoma than those with 3-4 protective genotypes (adjusted OR=0.71, 95% CI=0.53-0.97, P=0.028). Moreover, the rs2267755 C>T is significantly associated with messenger RNA (mRNA) expression of ALKBH1 and three of its surrounding genes, including SNWQ, ADCK1, and RPL21P10. These results suggest that the rs2267755 C>T may be a genetic variant to reduce neuroblastoma risk.