Polymorphisms in the Tumor Necrosis Factor Genes Are Associated with Breast Cancer in the Moroccan Population

The functional TNF-α-308G > a single-nucleotide polymorphism (rs1800629): association with the predictive indices of breast cancer carcinogenesis

BACKGROUND

Compared with all other cancer types, Breast cancer (BC) among women has now exceeded them all as the primary reason for cancer worldwide. The BC represents 11.7% of all cancer cases and accounts for a predestined 2.3 million new cases. It is the fourth primary reason for cancer-associated deaths in women. With a staggering 200-400% increase in the relative incidence of BC in Egypt, there is an urgent need for new diagnostic or predictive markers.

PURPOSE

The current investigation aims to explore the connection of the functional TNF-α-308G > A (rs1800629) single-nucleotide polymorphism (SNP) with different breast cancer predictive indices.

METHODS

The ARMS-PCR method was used for genotyping TNF-α-308G > A SNP. Three groups were recruited for the study: 79 patients with benign breast inflammation (BBI); 163 with breast cancer (BC) and 144 controls (C).

RESULTS

The TNF-α-308G > A SNP was distributed among different groups in a unique pattern; in the control group 63.9% of cases were in the GG, 34% were in the GA, and 2.1% were in the AA. The BC group had 14% GG, 79% GA, and 7% AA, while the BBI group had 24% GG, 76% GA, and 0% AA. The AA genotype and A allele represented a strong significant correlation with risk factors in the BC group (ORAA: 14.67 [95% CI = 3.78-56.91] and ORA: 0.27 [95% CI = 0.19-0.39], respectively; P < 0.0001) in contrast to the control group. However, in the BBI group, a strong significant correlation was noted with the GA genotype (ORGA: 5.93 [95% CI = 3.18-11.04] P < 0.0001). In the BC group, the AA genotype shows a significant increase in Nottingham Prognostic Index (NPI) in positive ER and PR in contrast to the relevant negative ones (P = 0.02 and 0.002, respectively). However, the GA genotype significantly increased NPI in positive Her2 and metastatic patients (P = 0.03 and 0.01, respectively).

CONCLUSION

This research is the first to correlate TNF-α-308G > A (rs1800629) SNP in Egyptian BC patients. The A allele, GA & AA genotypes, and the Overdominant model of the TNF-α-308G > A gene variants were recorded as prognostic risk factors for BC carcinogenesis.

Evaluation of genetic and epigenetic changes of Tumor Necrosis Factor-Alpha gene in larynx cancer

BACKGROUND

Tumor Necrosis Factor-Alpha (TNF-α) is a proinflammatory cytokine that plays a role in inflammation, which is one of the hallmarks of cancer, and its polymorphic variants have been associated with disease risk in many cancers in the literature. The aim of this study was to investigate four different polymorphic variants, differential methylation and expression status of the TNF-α gene and to determine the associations between these variants and disease risk, and to evaluate the relationship between the results and clinical parameters. We purposed to investigate the genetic and epigenetic alterations of the TNF-α gene in larynx cancer (LC).

MATERIAL AND METHODS

After isolation of DNA/RNA from whole blood, tumor and normal tissue, polymorphic variant alleles differrential expression and methylation levels were analyzed by RFLP, semiquantitative RT-PCR, and restriction enzyme digestion, respectively. TNF-α expression and methylation levels were calculated using BIO1D software. The frequencies of the variants c.-238 G>A (rs361525), c.-857 C>T (rs1799724), c.-863 C>A (rs1800630), and c.-1031 T > C (rs1799964) in the promoter region of TNF-α in LC Turkish patients and healthy individuals were examined using the De-Finetti case-control program. Haplotype frequencies and linkage disequilibrium were analyzed using the SNPStats program.

RESULTS

The frequency of genotype c.-1031 T > C was significantly lower in patients than in healthy individuals [TT vs TC: OR (%95CI) = 7.00 (1.75-27.93), p = 0.003, χ2 = 8.76]. The heterozygous variant of - 857 was associated with recurrence [T vs G: OR (%95CI) = 0.15 (0.02-0.95), p = 0.02, χ2 = 4.86]. For c.-238 G>A, c.-857 C>T, and c.-863 C>A, there was no statistically significant difference between the patient and healthy group in terms of disease risk. A significant association was found between c.-1031 T > C and disease risk of LC. Decreased expression was detected in 46% (23/50) and increased expression in 54% (27/50) of tumor tissue samples compared to the matched normal tissues of patients. Methylation-related loss of expression was detected in 53.3% (16/30) of patients.

CONCLUSION

Our study is the first investigating four different polymorphic regions of the TNF-α promoter region and the expression/methylation status of TNF-α in the same LC patient and healthy cohort. According to our results, the c.-1031 T > C variant was reported to be significantly associated with a reduced risk of LC. In addition, the TNF-α variant c. -857 C>T suggests that it may be a potential biomarker for predicting the recurrence of LC. An association between c. -857 C>T variant and methylation-based expression status was observed.