p16 promoter hypermethylation is an important event in gastric carcinogenesis. It is the principle mechanism of p16 gene silencing. It is related to malignant tumor behavior. Detection of DNA methylation in serum may be a biomarker for early detection of gastric cancer.

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ObjectiveTo characterise the gut microbiome in subjects with and without polyps and evaluate the potential of the microbiome as a non-invasive biomarker to screen for risk of colorectal cancer (CRC).DesignPresurgery rectal swab, home collected stool, and sigmoid biopsy samples were obtained from 231 subjects undergoing screening or surveillance colonoscopy. 16S rRNA analysis was performed on 552 samples (231 rectal swab, 183 stool, 138 biopsy) and operational taxonomic units (OTU) were identified using UPARSE. Non-parametric statistical methods were used to identify OTUs that were significantly different between subjects with and without polyps. These informative OTUs were then used to build classifiers to predict the presence of polyps using advanced machine learning models.ResultsWe obtained clinical data on 218 subjects (87 females, 131 males) of which 193 were White, 21 African-American, and 4 Asian-American. Colonoscopy detected polyps in 56% of subjects. Modelling of the non-invasive home stool samples resulted in a classification accuracy >75% for Naïve Bayes and Neural Network models using informative OTUs. A naïve holdout analysis performed on home stool samples resulted in an average false negative rate of 11.5% for the Naïve Bayes and Neural Network models, which was reduced to 5% when the two models were combined.ConclusionGut microbiome analysis combined with advanced machine learning represents a promising approach to screen patients for the presence of polyps, with the potential to optimise the use of colonoscopy, reduce morbidity and mortality associated with CRC, and reduce associated healthcare costs.

We could detect colorectal cancer related genetic alterations by analyzing stool DNA with a sensitivity of 64% and 20% and a specificity of 95% and 100% for Long DNA and p16 respectively. A non-invasive molecular stool-based DNA testing can provide a screening strategy in high-risk individuals. However, additional testing on more samples is necessary from Iranian subjects to determine the exact specificity and sensitivity of these markers.

Reported associations between vitamin D receptor (VDR) polymorphism and type 1 diabetes mellitus vary across ethnic groups. We studied the association between type 1 diabetes and 4 VDR gene polymorphisms (Bb, Ff, Aa and Tt) in an Iranian population. A group of 69 patients with type 1 diabetes mellitus and 45 unrelated healthy subjects were recruited. The prevalence of VDR polymorphisms in 4 restriction fragment length polymorphism sites including BsmI, FokI, ApaI and TaqI were analysed in patients and controls. The frequencies of 3 genotypes (Aa, FF and Bb) were significantly higher in the patient group. The relationship between VDR gene polymorphisms and onset pattern of diabetes was not significant. There were no significant difference between the genotype frequencies and chronic complications of diabetes, but the relationship between the Ff genotype and ketoacidosis was significant. Our results differ from previous polymorphism studies in other regions.