Plasma Levels of Kynurenine, Soluble OX40 and Mir-138-5p Are Associated With Tumor-infiltrating Lymphocytes in Colorectal Cancer: An Exploratory Study.

BACKGROUND/AIM: Colorectal cancer (CRC) is one of leading cancers in terms of incidence and mortality. Interaction of tumor cells with the surrounding microenvironment plays a crucial role in the development and progression of CRC. Many pathways such as the kynurenine pathway, OX40/OX40L-mediated signaling and microRNAs targeting PD-L1 may be involved in CRC development by affecting T cell activation, thus creating an immune-deficient microenvironment. Herein, our goal was to assess the association between plasma levels of tryptophan (TRP), kynurenine (KYN), KYN/TRP ratio, soluble OX40 (sOX40) and PD-L1-targeting miR-138-5p and CRC risk. PATIENTS AND METHODS: Plasma concentrations of TRP and KYN were determined by HPLC; sOX40 was measured by ELISA whereas circulating miR-138-5p was measured by quantitative PCR in pathologically confirmed CRC patients and colonoscopy-verified CRC-free controls without polyps (control group 1) and with polyps (control group 2). RESULTS: We found significantly lower plasma levels of TRP in CRC patients compared to control groups which resulted in significantly higher KYN/TRP ratio in CRC patients than in the controls (p=0.007). Plasma levels of sOX40 did not significantly differ between groups. The levels of circulating miR-138-5p were significantly lower in CRC patients (relative median value 0.02) than in the control groups (relative median values 0.2 and 4.29, respectively) (p=0.03). Plasma levels of KYN and sOX40 were considerably higher in patients with no tumor-infiltrating lymphocytes (TILs) than those with TILs whereas circulating miR-138-5p had opposite expression pattern in plasma. CONCLUSION: The kynurenine pathway and miR-138-5p are associated with CRC risk and plasma levels of KYN, sOX40 and miR-138-5p are related to TILs, making them possible target molecules in possible immunotherapeutic targets for CRC.

Fragmentation Analysis of Plasma DNA Reveals Its Prognostic Value in Gastric Cancer.

BACKGROUND: Gastric cancer (GC) is a common cause of cancer-related deaths. The poor clinical outcome in GC patients is partially associated with a lack of appropriate diagnostic and prognostic biomarkers. In the present study, we evaluated the diagnostic and prognostic values of cell-free DNA (cfDNA) integrity and the concentration of circulating nucleosomes (cNUCs). METHODS: In the study, 40 GC patients and 55 GC-free individuals were enrolled. Cell-free DNA integrity was calculated as the ratio of concentration of the longer ACTB (beta-actin) gene fragment to that of the shorter ACTB fragment, measured using quantitative PCR. Circulating nucleosomes were measured by an ELISA-based approach. RESULTS: We found that cfDNA integrity is higher in GC patients than in the control subjects (relative median values 0.51 vs. 0.38, respectively, P = .56) indicating prominent abundance of longer fragments in the patients. The patients with larger tumors (T3-4) had significantly higher cfDNA integrity than those with T1-T2 tumors. We also found GC patients to have higher concentrations of cNUCs in their plasma (relative median values 3.64 vs. 3.1). Importantly, the patients with high cfDNA integrity (i.e., lower fragmentation) had longer overall survival rates at 3 years than those with lower cfDNA integrity (76.5% vs. 38.9%, P = .02). CONCLUSION: Cell-free DNA fragmentation has a prognostic value. However, it has no diagnostic value in GC.

Diagnostic and prognostic value of circulating lncRNA H19 in gastric cancer.

Gastric cancer (GC) is among the most frequent malignant diseases. Despite advances in treatment, the clinical outcome of patients with GC remains poor. The establishment of novel biomarkers is urgently required for early detection, treatment evaluation and prognostic assessment. Non-coding RNAs (ncRNAs) are a key topic of intensive research due to their potential applications in the field of oncology. The long ncRNA H19 has been frequently reported as overexpressed in many cancers including GC. In the present study, the diagnostic and prognostic value of circulating H19 in GC was assessed. Higher levels of circulating H19 were identified in GC patients (n=40) compared with a control group consisting of endoscopy-verified GC-free individuals (n=42; median levels relative to GAPDH, 58.4 vs. 29.9; P=0.027). Patients with smaller tumor sizes (<5 cm) exhibited higher H19 in their circulation compared with those with larger tumors (≥5 cm; P=0.04). Plasma levels of H19 declined significantly upon surgical removal of gastric tumors as documented in a subset of patients [n=20; relative median levels, 146.0 vs. 15.0 (pre-surgery); P=0.003]. However, it was identified that H19 had no prognostic role in GC by the Kaplan-Meier method. In conclusion, the present findings identify H19 as potential diagnostic marker in GC.

MicroRNA Expression Profiles in Papillary Thyroid Carcinoma, Benign Thyroid Nodules and Healthy Controls.

MicroRNAs (miRNAs) represent a class of short endogenous non-coding RNAs that negatively regulate gene expression at the post-transcriptional level in many biological processes, including proliferation, differentiation, stress response and apoptosis. In this study we analyzed a set of seven miRNA molecules in sera of patients with papillary thyroid cancer, multinodular goiter and healthy controls to identify miRNA molecules that may have utility as markers for PTC. MiR-21 serum levels in the preoperative PTC and MG groups were significantly higher than the control group. Likewise, postoperative levels of miR-151-5p, miR-221 and miR-222 were significantly lower in patients with PTC. When serum miRNA levels were evaluated according to stage, postoperative levels of miR-151-5p and miR-222 were significantly lower in patients with advanced stages of the disease. The miRNA levels were also found associated with the size of the primary tumor. Our data imply that specific miRNA molecules which are differentially expressed in thyroid tumors may play role in the development of papillary thyroid carcinoma.

Analysis of circulating microRNAs during adjuvant chemotherapy in patients with luminal A breast cancer.

Breast cancer is a complex disease displaying different profiles involving genetic as well as epigenetic factors. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression. Recent studies demonstrated that miRNAs may display great potential for the development of novel biomarkers and therapeutic targets. In the present study, the levels of miR-21 and miR-145 were analyzed in the peripheral blood of 52 patients with luminal A breast cancer. miRNA expression was determined in serum samples from matched pre- and post-treatment patients with breast cancer by quantitative polymerase chain reaction. There were no statistically significant differences in miR-145 and miR-21 levels between pre- and post-treatment samples. In addition, the miRNA levels were not found to be associated with the clinical parameters.

Promoter and histone methylation and p16(INK4A) gene expression in colon cancer.

The inactivation of the cyclin-dependent kinase inhibitor p16(INK4A) gene by hypermethylation is observed in numerous types of cancer. New findings indicate that DNA and histone methylation act in concert in gene silencing. In this study, we investigated the methylation status of the p16(INK4A) gene promoter and the histone 3 lysine 9 residue in the tumors and matched normal tissue samples from patients with colorectal cancer and analyzed their association with gene expression. The methylation and expression of the p16(INK4A) gene were analyzed by real-time PCR, and histone methylation was analyzed by chromatin immunoprecipitation followed by real-time PCR. p16(INK4A) expression was significantly higher in the tumors compared to normal tissue. Mono-, di- and trimethylation levels of the H3K9 residue were similar in the tumor and normal tissue samples. We did not observe any significant correlation between p16(INK4A) methylation or expression and clinical parameters. Our results suggest that epigenetic modifications of the p16(INK4A) gene and histone lysine methylation do not play a major role in colon carcinogenesis.