RAD51 135G>C polymorphism in esophageal cancer and meta-analysis in gastrointestinal tract cancers

Background

A functional single-nucleotide polymorphism (SNP), 135G>C in the 5'UTR of the RAD51 gene, affects gene transcription activity with implications for the repair of damaged DNA related to tumorigenesis. Previous limited reported genetic studies to link the 135G>C polymorphism of RAD51 gene to the risk of gastrointestinal tract (GIT) cancers, especially esophageal cancer (EC), have been inconclusive.

Materials and Methods

The polymorphism was evaluated by RFLP-PCR in 252 EC patients and 252 healthy controls from Amritsar, Punjab, India, for case-control study. For a meta-analysis, a total of 78 studies on GIT cancers were assessed, out of which 14 eligible studies (including the present study) comprising 2842 cases and 3224 controls were included. Odds ratios (ORs) with 95% confidence intervals (CIs) and Chi-square test were used to assess the association in different inheritance models.

Results

The GC genotype (OR: 0.45, 95% CI: 0.29-0.68) and C allele (OR: 0.52, 95% CI: 0.36-0.75) were significantly lower (P = 0.0005) in cases as compared to controls. There was no significant association with any genetic model in the meta-analysis.

Conclusion

C allele provides protection for EC in the studied population contrary to previous reports in Polish, Chinese population probably due to ethic differences. Compared with previous meta-analysis on individual GIT cancers, present meta-analysis included all GIT cancers but found no association.

Association of ATG10 rs1864183, ATG16L1 rs2241880 and miR-126 with esophageal cancer

BACKGROUND

In India, esophageal cancer (EC) is among the major cause of cancer-related deaths in both sexes. In recent past, autophagy has emerged as one of the crucial process associated with cancer. In the development of EC, the role of autophagy and the precise molecular mechanism involved has yet to be fully understood. Recently, a small number of studies have proposed how variations in autophagy genes affect the growth and development of EC. Micro-RNA's are also known to play a critical role in the development of EC. Here, we examined the relationship between the risk of EC and two single-nucleotide polymorphisms (SNPs) in the key autophagy genes, ATG10 rs1864183 and ATG16L1 rs2241880. We also analyzed the association of miR-107 and miR-126 with EC as these miRNA's are associated with autophagy.

METHODS AND RESULTS

A total of 230 EC patients and 230 healthy controls from North-west Indian population were enrolled. ATG10 rs1864183 and ATG16L1 rs2241880 polymorphism were analyzed using TaqMan genotyping assay. Expression levels of miR-107 and miR-126 were analyzed through quantitative PCR using SYBR green chemistry. We found significant association of CT + CC genotype (OR 0.64, p = 0.022) in recessive model for ATG10 rs1864183 polymorphism with decreased EC risk. For ATG16L1 rs2241880 polymorphism significant association for AG genotype (OR 1.48, p = 0.05) and G allele (OR 1.43, p = 0.025) was observed for increased EC risk. Expression levels of miR-126 were also found to be significantly up regulated (p = 0.008).

CONCLUSION

Our results suggest that ATG10 rs1864183, ATG16L1 rs2241880 and miR-126 may be associated with esophageal carcinogenesis and warrant further investigation.

miR-107 and miR-126 and Risk of Breast Cancer: A Case-Control Study

Background: Micro RNAs are new diagnostic markers and therapeutic targets in breast cancer research. miR-107 and miR-126 have been reported to be linked with the pathogenesis of breast cancer. The present study investigates the levels of expression of miR-107 and miR-126 in patients with breast cancer to find their correlation with the risk of breast cancer in Amritsar, Punjab, Northwest India. Material and Methods: In total, 200 subjects, 100 patients with breast cancer and 100 controls, were enrolled to screen the expression of miR-107 and miR-126 using quantitative reverse transcription polymerase chain reaction (RT-PCR) technique. The Livak method (2-ΔΔCt) was used to calculate the fold change of the expression of micro RNAs. Student t-test was used to calculate the significant change in the expression of miRNAs in patients as compared with controls. Spearman rank correlation coefficient and ROC were conducted. The value of p < 0.05 was considered to indicate a statistically significant difference. Results: miR-107 was downregulated in patients with breast cancer as compared with controls (fold change = 0.467; p = 0.114) but not statistically significant. The expression of miR-126 was found to be 5.37 times elevated in patients with breast cancer, specifically in stage I and stage III patients (p = 0.009), compared with controls, which may indicate its oncogenic activity. The ROC analyses revealed that miR-126 could be a potential diagnostic marker. In conclusion oncogenic behavior of miR-126 is suggestive of its role in pathogenesis in patients with breast cancer.