Hepatocyte Growth Factor in Blood and Gastric Cancer Risk: A Nested Case-Control Study

The Association of rs5745687 Polymorphism Located at HGF Gene with Risk of Gastric and Breast Cancer in the Helicobacter Positive Patients of Isfahan Population

Background: Hepatocyte growth factor (HGF) protein regulates cell growth, motility, and morphogenesis in a variety of cells and tissues by binding to the HGF receptor. The rs5745687 SNPs in the introns of the HGF gene could affect the splicing and expression of HGF mRNA. Objectives: In this study, the genotype frequency of rs5745687 in breast cancer (BC) and gastric cancer (GC) (positive helicobacter) patients has been investigated and compared with the healthy controls in the Isfahan population. Methods: Firstly, initial bioinformatics studies were done. Then, according to the results, bioinformatics High-Resolution Melt (HRM) and Real-Time PCR were recruited to determine genotypes rs5745678 for 432 participants in the case-control analysis (84 GC with 126 healthy control samples, as well as 111 BC cases with 111 normal controls). The conditional logistic regression model was used to measure odds ratios (OR) and 95% confidence intervals (CI) to produce these cancers based on genotype frequency. Results: The homozygote genotype of the mutant (G) allele of rs5745678 has a significant association with the lower risk of gastric cancer (P-value < 0.0001) and this allele can increase the risk of GC in a co-dominant model (OR: 5.541, P-value < 0.0001). Also, the rs5745678 SNP had a significant association with the clinicopathological features (age, smoking, H. Pylori infection) in GC patients. Conclusions: The presence of a single G allele in rs5745678 heterozygote (AG/AA) and co-dominant (AG/AA+GG) models could significantly impact GC pathogenicity in different ways. There was no significant correlation between the rs5745678 polymorphism and BC (P-value: 0.671) in the studied sample size.

Systematic review of gastric cancer-associated genetic variants, gene-based meta-analysis, and gene-level functional analysis to identify candidate genes for drug development

Objective: Despite being a powerful tool to identify novel variants, genome-wide association studies (GWAS) are not sufficient to explain the biological function of variants. In this study, we aimed to elucidate at the gene level the biological mechanisms involved in gastric cancer (GC) development and to identify candidate drug target genes.

Materials and methods: We conducted a systematic review for GWAS on GC following the PRISMA guidelines. Single nucleotide polymorphism (SNP)-level meta-analysis and gene-based analysis (GBA) were performed to identify SNPs and genes significantly associated with GC. Expression quantitative trait loci (eQTL), disease network, pathway enrichment, gene ontology, gene-drug, and chemical interaction analyses were conducted to elucidate the function of the genes identified by GBA.

Results: A review of GWAS on GC identified 226 SNPs located in 91 genes. In the comprehensive GBA, 44 genes associated with GC were identified, among which 12 genes (THBS3, GBAP1, KRTCAP2, TRIM46, HCN3, MUC1, DAP3, EFNA1, MTX1, PRKAA1, PSCA, and ABO) were eQTL. Using disease network and pathway analyses, we identified that PRKAA, THBS3, and EFNA1 were significantly associated with the PI3K-Alt-mTOR-signaling pathway, which is involved in various oncogenic processes, and that MUC1 acts as a regulator in both the PI3K-Alt-mTOR and P53 signaling pathways. Furthermore, RPKAA1 had the highest number of interactions with drugs and chemicals.

Conclusion: Our study suggests that PRKAA1, a gene in the PI3K-Alt-mTOR-signaling pathway, could be a potential target gene for drug development associated with GC in the future.

Systematic Review Registration: website, identifier registration number.

Variation in Plasma Levels of TRAF2 Protein During Development of Squamous Cell Carcinoma of the Oral Tongue

As early detection is crucial for improvement of cancer prognosis, we searched for biomarkers in plasma from individuals who later developed squamous cell carcinoma of the oral tongue (SCCOT) as well as in patients with an already established SCCOT. Levels of 261 proteins related to inflammation and/or tumor processes were measured using the proximity extension assay (PEA) in 179 plasma samples (42 collected before diagnosis of SCCOT with 81 matched controls; 28 collected at diagnosis of SCCOT with 28 matched controls). Statistical modeling tools principal component analysis (PCA) and orthogonal partial least square - discriminant analysis (OPLS-DA) were applied to provide insights into separations between groups. PCA models failed to achieve group separation of SCCOT patients from controls based on protein levels in samples taken prior to diagnosis or at the time of diagnosis. For pre-diagnostic samples and their controls, no significant OPLS-DA model was identified. Potentials for separating pre-diagnostic samples collected up to five years before diagnosis (n = 15) from matched controls (n = 28) were seen in four proteins. For diagnostic samples and controls, the OPLS-DA model indicated that 21 proteins were important for group separation. TNF receptor associated factor 2 (TRAF2), decreased in pre-diagnostic plasma (< 5 years) but increased at diagnosis, was the only protein showing altered levels before and at diagnosis of SCCOT (p-value < 0.05). Taken together, changes in plasma protein profiles at diagnosis were evident, but not reliably detectable in pre-diagnostic samples taken before clinical signs of tumor development. Variation in protein levels during cancer development poses a challenge for the identification of biomarkers that could predict SCCOT development.

Plasma HGF concentration in patients with brain tumors

The Hepatocyte Growth Factor is a strong mitogenic factor and seems to play important role in tumor angiogenesis. The purpose of this study was to analyse the plasma concentration of this factor in patients treated surgically because of intracranial tumors. The study included 47 patients, both sexes treated surgically for intracranial tumors and 30 adult volunteers of both sexes, without cancer diagnosis. In study group 4 measurements of plasma HGF were taken: measurement 1: within 24 hours to 1 hour before the operation (preoperative), measurement 2: on the first day after the operation, i.e. after 24 hours, measurement 3: between the third and fifth day following the treatment, i.e. within 72-120 hours, and measurement 4: on the seventh day after the operation, i.e. after 840 hours. In control group only one measurement was taken. The distribution of the analyzed parameters was different from the normal distribution, therefore nonparametric statistics were used. The result values are presented in the form of a median (Me). The analysis revealed that HGR plasma levels in the patients with intracranial tumors in all 4 measurements (Me1 = 543.16 pg/ml, Me2 = 762.59 pg/ml, Me3 = 819.82 pg/ml, Me4 = 804.82 pg/ml) in the perioperative period were elevated in comparison to healthy subjects (Me = 361.04 pg/ml). The association has been shown to exist between postoperative HGF plasma levels and the clinical condition of patients with intracranial tumors (p = 0.0342). Postoperative HGF levels correlated negatively with the patients' postoperative condition. It was also found that in patients with supratentorial tumors HGF plasma levels were higher (Me = 557.74 pg/ml) in comparison to patients with posterior fossa tumors (Me = 325.00 pg/ml). These results suggest increased angiogenic and mitogenic activity in patients with intracranial tumors and its even greater intensity in the postoperative period. Greater angiogenic activity appears to occur in patients with supratentorial tumors.