---

Background and purpose: Tuberculosis is among the leading causes of death from infectious diseases in the world. According to World Health Organization (WHO), the estimated rate of TB in Iran was 21 per 100,000 populations in 2015. The present study was designed to evaluate the genetic diversity and transmission dynamics of Mycobacterium tuberculosis in Tehran, Iran.

Materials and methods: A total of 80 isolates of Mycobacterium tuberculosis was cultured from TB patients attending a teaching hospital in Tehran, Iran from January 2015 to December 2016. Standard 15-locus Mycobacterial Interspersed Repeat Units/Variable Numbers of Tandem Repeat (MIRU-VNTR) typing was applied to genotype clinical isolates.

Results: There were 78 different VNTR profiles comprising 2 clusters and 76 unique patterns. The Hunter – Gaston discriminatory index (HGDI) was 0.990, indicating a high power of discrimination for MIRU-VNTR typing. The QUB26 and MTUB21 loci were designated as highly discriminative.

Conclusion: The high genetic diversity among Mycobacterium tuberculosis isolates suggests that transmission may have been caused by different sources.

---

Background and purpose: Gastric cancer is the most common cancer associated with high mortality worldwide. One of the genes that is down-regulated in gastric cancer, is the SIRT3 that encodes the histone deacetylase enzyme. There is a variable number tandem repeat (VNTR) polymorphism in the intron 5 of SIRT3 gene and evidence shows that expression of SIRT3 gene increases by increase in the number of repeats. According to the deregulation of SIRT3 gene expression in gastric cancer and the effect of intron 5 VNTR polymorphism in the transcription, we investigated the association between intron 5 VNTR polymorphism of SIRT3 gene and the risk of developing gastric cancer.
Materials and methods: A case-control study was performed in 116 patients with gastric cancer (attending Isfahan Omid Hospital, Iran) and healthy controls (n= 116). After DNA extraction, all samples were genotyped using PCR and electrophoresis techniques and the results were analyzed applying logistic regression and Chi-square tests.
Results: In addition to the alleles that have been reported so far, alleles with 8 and 9 repeats were observed too, in this study. The results showed that genotype 4-1 increases significantly the risk of gastric cancer (P=0.028, OR= 13.00).
Conclusion: Some variants of intron 5 VNTR polymorphism SIRT3 gene is associated with risk of developing gastric cancer.