Assessing genetic polymorphisms using DNA extracted from cells present in saliva samples

<p>Abstract</p> <p>Background</p> <p>Technical advances following the Human Genome Project revealed that high-quality and -quantity DNA may be obtained from whole saliva samples. However, usability of previously collected samples and the effects of environmental conditions on the samples during collection have not been assessed in detail. In five studies we document the effects of sample volume, handling and storage conditions, type of collection device, and oral sampling location, on quantity, quality, and genetic assessment of DNA extracted from cells present in saliva.</p> <p>Methods</p> <p>Saliva samples were collected from ten adults in each study. Saliva volumes from .10-1.0 ml, different saliva collection devices, sampling locations in the mouth, room temperature storage, and multiple freeze-thaw cycles were tested. One representative single nucleotide polymorphism (SNP) in the catechol-<it>0</it>-methyltransferase gene (COMT rs4680) and one representative variable number of tandem repeats (VNTR) in the serotonin transporter gene (5-HTTLPR: serotonin transporter linked polymorphic region) were selected for genetic analyses.</p> <p>Results</p> <p>The smallest tested whole saliva volume of .10 ml yielded, on average, 1.43 ± .77 μg DNA and gave accurate genotype calls in both genetic analyses. The usage of collection devices reduced the amount of DNA extracted from the saliva filtrates compared to the whole saliva sample, as 54-92% of the DNA was retained on the device. An "adhered cell" extraction enabled recovery of this DNA and provided good quality and quantity DNA. The DNA from both the saliva filtrates and the adhered cell recovery provided accurate genotype calls. The effects of storage at room temperature (up to 5 days), repeated freeze-thaw cycles (up to 6 cycles), and oral sampling location on DNA extraction and on genetic analysis from saliva were negligible.</p> <p>Conclusions</p> <p>Whole saliva samples with volumes of at least .10 ml were sufficient to extract good quality and quantity DNA. Using 10 ng of DNA per genotyping reaction, the obtained samples can be used for more than one hundred candidate gene assays. When saliva is collected with an absorbent device, most of the nucleic acid content remains in the device, therefore it is advisable to collect the device separately for later genetic analyses.</p

Genomic Analysis of Vascular Invasion in HCC Reveals Molecular Drivers and Predictive Biomarkers

Vascular invasion is a critical risk factor for hepatocellular carcinoma (HCC) recurrence and poor survival. The molecular drivers of vascular invasion in HCC are largely unknown. Deciphering the molecular landscape of invasive HCC will help identify novel therapeutic targets and noninvasive biomarkers. To this end, we undertook this study to evaluate the genomic, transcriptomic, and proteomic profile of tumors with vascular invasion using the multi-platform cancer genome atlas (TCGA) data (n=373). In the TCGA liver hepatocellular carcinoma (LIHC) cohort, macrovascular invasion was present in 5% (n=17) of tumors and microvascular invasion in 25% (n=94) of tumors. Functional pathway analysis revealed that the MYC oncogene was a common upstream regulator of the mRNA, miRNA and proteomic changes in vascular invasion. We performed comparative proteomic analyses of invasive human HCC and MYC driven murine HCC and identified fibronectin to be proteomic biomarker of invasive HCC (mouse Fn1 p= 1.7 × 10(−11); human FN1 p=1.5 × 10(−4)) conserved across the two species. Mechanistically, we show that FN1 promotes the migratory and invasive phenotype of HCC cancer cells. We demonstrate tissue overexpression of fibronectin in human HCC using a large independent cohort of human HCC tissue microarray (n=153; p<0.001). Lastly, we showed that plasma fibronectin levels were significantly elevated in patients with HCC (n=35, mean=307.7 μg/ml, SEM=35.9) when compared to cirrhosis (n=10, mean=41.8 μg/ml, SEM=13.3; p<0.0001). CONCLUSION: Our study evaluates the molecular landscape of tumors with vascular invasion, identifying distinct transcriptional, epigenetic and proteomic changes driven by the MYC oncogene. We show that MYC upregulates fibronectin expression which promotes HCC invasiveness. In addition, we identify fibronectin to be a promising non-invasive proteomic biomarker of vascular invasion in HCC

Advances in gluten-free bread technology

The unattractive appearance of gluten-free bread still remains a challenge in gluten-free breadmaking. In response to this, additives such as dairy products, soya and eggs have been used to improve the quality of gluten-free bread, but with limited success. In recent years, enzymes (transglutaminase and cyclodextrinase) and hydrocolloids (carboxymethylcellulose and hydroxypropylmethylcellulose) have become the main focus for the improvement of gluten-free bread. Transglutaminase has been shown to improve the dough viscoelasticity and decrease crumb hardness (6.84–5.73 N) of the resulting bread. Cyclodextrinase also enhances dough viscoelasticity, resulting in an improvement of 53% in shape index and crumb firmness. Similarly, hydroxypropylmethylcellulose improves gas retention and water absorption of dough and reduces crumb hardening rate of the resulting bread, while carboxymethylcellulose significantly increases dough elasticity (60–70 BU) and bread volume (230–267 cm3 /100 g bread)