Isolation of DNA from blood and buccal swabs in adequate quantities is an integral part of forensic research and analysis. The present study was performed to determine the quality and the quantity of DNA extracted from four commonly available samples and to estimate the time duration of the ensuing PCR amplification. Here, we demonstrate that hair and urine samples can also become an alternate source for reliably obtaining a small quantity of PCR-ready DNA. We developed a rapid, cost-effective, and noninvasive method of sample collection and simple DNA extraction from buccal swabs, urine, and hair using the phenol-chloroform method. Buccal samples were subjected to DNA extraction, immediately or after refrigeration (4 -6°C) for 3 days. The purity and the concentration of the extracted DNA were determined spectrophotometerically, and the adequacy of DNA extracts for the PCR-based assay was assessed by amplifying a 1030-bp region of the mitochondrial D-loop. Although DNA from all the samples was suitable for PCR, the blood and hair samples provided a good quality DNA for restriction analysis of the PCR product compared with the buccal swab and urine samples. In the present study, hair samples proved to be a good source of genomic DNA for PCR-based methods. Hence, DNA of hair samples can also be used for the genomic disorder analysis in addition to the forensic analysis as a result of the ease of sample collection in a noninvasive manner, lower sample volume requirements, and good storage capability.

BackgroundGastric cancer (GC) is one of the most frequently diagnosed digestive tract cancers and carries a high risk of mortality. Acetaldehyde (AA), a carcinogenic intermediate of ethanol metabolism contributes to the risk of GC. The accumulation of AA largely depends on the activity of the major metabolic enzymes, alcohol dehydrogenase and aldehyde dehydrogenase encoded by the ADH (ADH1 gene cluster: ADH1A, ADH1B and ADH1C) and ALDH2 genes, respectively. This study aimed to evaluate the association between genetic variants in these genes and GC risk in West Bengal, India.MethodsWe enrolled 105 GC patients (cases), and their corresponding sex, age and ethnicity was matched to 108 normal individuals (controls). Genotyping for ADH1A (rs1230025), ADH1B (rs3811802, rs1229982, rs1229984, rs6413413, rs4147536, rs2066702 and rs17033), ADH1C (rs698) and ALDH2 (rs886205, rs968529, rs16941667 and rs671) was performed using DNA sequencing and RFLP.ResultsGenotype and allele frequency analysis of these SNPs revealed that G allele of rs17033 is a risk allele (A vs G: OR = 3.67, 95% CI = 1.54–8.75, p = 0.002) for GC. Significant association was also observed between rs671 and incidence of GC (p = 0.003). Moreover, smokers having the Lys allele of rs671 had a 7-fold increased risk of acquiring the disease (OR = 7.58, 95% CI = 1.34–42.78, p = 0.009).ConclusionIn conclusion, rs17033 of ADH1B and rs671 of ALDH2 SNPs were associated with GC risk and smoking habit may further modify the effect of rs671. Conversely, rs4147536 of ADH1B might have a protective role in our study population. Additional studies with a larger patient population are needed to confirm our results.Electronic supplementary materialThe online version of this article (10.1186/s12885-017-3713-7) contains supplementary material, which is available to authorized users.

Gastric cancer is one of the most common malignancies in India. DNA repair gene or xenobiotic pathway gene polymorphisms have recently been shown to affect individual susceptibility to gastric cancer. Here, the possible interaction between common polymorphisms in X-ray repair cross complementing group I (XRCC1) gene and glutathione S-transferase (GST) genes (GSTM1, GSTT1 and GSTP1), smoking and alcohol consumption and overall survival in gastric cancer patients were evaluated. In this population-based case control study, 70 gastric cancer patients and 82 healthy controls were enrolled. The epidemiological data were collected by a standard questionnaire, and blood samples were collected from each individual. XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphisms were determined by polymerase chain reaction and direct DNA sequencing. GSTM1 and GSTT1 null polymorphisms and GSTP1 Ile105Val polymorphism were identified by multiplex polymerase chain reaction and restriction fragment length polymorphism (RFLP), respectively. The risk of gastric cancer was significantly elevated in individuals with XRCC1 Arg/Gln +Gln/Gln (p = 0.031; odds ratio = 2.32; 95 % confidence interval (CI) 1.07-5.06) and GSTP1 Val/Val genotype (p = 0.009; odds ratio = 8.64; 95 % CI 1.84-40.55). An elevated risk for GC was observed in smokers and alcohol consumers carrying GSTP1 Ile/Val +Val/Val genotype (p = 0.041; odds ratio = 3.71; 95 % CI 0.98-14.12; p = 0.002; odds ratio = 12.31; 95 % CI 1.71-88.59). These findings suggest that XRCC1 rs25487 and GSTP1 rs1695 can be considered as a risk factor associated with gastric cancer and might be used as a molecular marker for evaluating the susceptibility of the disease.

BackgroundThe role of adenomatous polyposis coli (APC) gene in mitosis might be critical for regulation of genomic stability and chromosome segregation. APC gene mutations have been associated to have a role in colon cancer and since gastric and colon tumors share some common genetic lesions, it is relevant to investigate the role of APC tumor suppressor gene in gastric cancer.MethodsWe investigated for somatic mutations in the Exons 14 and 15 of APC gene from 40 diffuse type gastric cancersamples. Rabbit polyclonal anti-APC antibody was used, which detects the wild-type APC protein and was recommended for detection of the respective protein in human tissues. Cell cycle analysis was done from tumor and adjacent normal tissue.ResultsAPC immunoreactivity showed positive expression of the protein in stages I, II, III and negative expression in Stages III and IV. Two novel deleterious variations (g.127576C > A, g.127583C > T) in exon 14 sequence were found to generate stop codon (Y622* and Q625*)in the tumor samples. Due to the generation of stop codon, the APC protein might be truncated and all the regulatory features could be lost which has led to the down-regulation of protein expression. Our results indicate that aneuploidy might occurdue to the codon 622 and 625 APC-driven gastric tumorigenesis, in agreement with our cell cycle analysis. The APC gene function in mitosis and chromosomal stability might be lost and G1 might be arrested with high quantity of DNA in the S phase. Six missense somatic mutations in tumor samples were detected in exon 15 A-B, twoof which showed pathological and disease causing effects based on SIFT, Polyphen2 and SNPs & GO score and were not previously reported in the literature or the public mutation databases.ConclusionThe two novel pathological somatic mutations (g.127576C > A, g.127583C > T) in exon 14 might be altering the protein expression leading to development of gastric cancer in the study population. Our study showed that mutations in the APC gene alter the protein expression and cell cycle regulation in diffuse type gastric adenocarcinoma.Electronic supplementary materialThe online version of this article (doi:10.1186/s12881-017-0427-2) contains supplementary material, which is available to authorized users.

Mitochondrial DNA (mtDNA) is known for its high frequencies of polymorphisms and mutations as it is prone to oxidative stress. The aim of the present study is to assess the novel mutations in mitochondrial genes from blood samples among the breast cancer patients from a less studied Northeast Indian population. D, B, L haplogroups were observed in the cancer samples and a total of 44 mtDNA D-loop sequence variations at 42 distinct nucleotide positions were found. All the sequence variations were transitional substitutions and 6 were heteroplasmic states, except for a cytosine copy number change (9C/8C) at np 303e309 in three samples examined. A total of 88 Cytochrome Oxidase C subunit I (COXI) sequence differences with respect to the Revised Cambridge Reference Sequence (rCRS) were identified including 20 missense variants with 100 % sample mutation frequency. All 20 missense mutations are highly conserved with a Cumulate Index of 100 %. Among 88 COXI mutations, 24 (13 were Non-Synonymous and 11 were Synonymous) were not previously reported (novel mutation) in the literature or the public mtDNA mutation databases. Analysis of three-dimensional structure of COXI open reading frame (ORF) predicted the effect of one single codon (96R > C, 217T > I, 224-225GG > EE and 227D > T) mutations located in the signal peptide binding position. Analysis of mitochondrial DNA mutations, as a viable alternative, has the advantage of being capable of detecting inherent risk factors for breast cancer development.