Expression and Content of Protein LC3B in Gastric Cancer Tissue, Relationship with Expression of mTOR, AMPK in Gastric Cancer Tissue and HER2 and PD-L1 Status of the Tumor

Analysis of HER2 status of the tumor and expression of mTOR, AMPK showed a decrease in mTOR mRNA level in HER2⁺ tumors in comparison with HER- status. The appearance of PD-L1⁺ transformed cells in the tumor was associated with increased expression of the LC3B gene and elevated content of the corresponding protein measured after treatment.

AKT/mTOR Signal Cascade and Expression of PD-1, PD-L1, and PD-L2 in Gastric Cancer

The peculiarities of gastric cancer development associated with the expression levels of components of the AKT/mTOR signaling cascade and PD, PD-L1, PD-L2 have not yet been identified. We revealed the fundamental changes in the expression AKT/mTOR and PD receptors and their ligands associated with dissemination of gastric cancer. An increase in the mRNA level of all components of this cascade was demonstrated. The expression of mTOR and AKT decreased against the background of enhanced expression of PTEN phosphatase. The increase in the expression of PD-1 receptors and PD-L1 and PD-L2 ligands was most pronounced in patients with distant metastases.

[Expression of genes involved in retinoic acid biosynthesis in human gastric cancer]

All-trans-retinoic acid (ATRA) is the main biologically active metabolite of retinol (vitamin A) that is required for the regulation of such processes as embryogenesis, tissue differentiation, proliferation, and others. Multiple alcohol, retinol and retinaldehyde dehydrogenases (ADHs, RDHs and RALDHs) as well as aldo-keto reductases (AKRs) catalyze the biosynthesis of retinoic acid in humans. For many normal and neoplastic tissues, the key ATRA-synthesizing enzymes remain unknown. We identified ATRA-generating genes that are expressed in normal and malignant gastric tissues using the transcriptomic database analysis. Quantitative changes in the expression levels of these genes in gastric cancer were determined by semi-quantitative RT-PCR and real-time PCR. Significant decreases in the mRNA levels of genes encoding enzymes that catalyze the reversible oxidation/reduction of retinol and retinaldehyde (ADH4, ADH1B, ADH1C, RDHL, AKR1B10, AKR1B1, and RDH12), as well as the oxidation of retinaldehyde (RALDH1) were revealed in most of the tumor samples. The sharp reduction in the expression levels of genes encoding the key enzymes that convert retinol and retinaldehyde to retinoic acid could lead to a significant decrease in the content of ATRA--the transcriptional regulator of many genes, which in turn can lead to a dysregulation of cell proliferation/differentiation and initiate cancer development.

[Identification of proteins overexpressed in malignant gastric tumors: comparison of the results of 2-De and bioinformatics search]

Comparison of protein expression in intestinal and diffuse stomach tumors by 2D gel electrophoresis led to identification of three proteins (SOD2, S100A6, and TXN), which are overexpressed in tumors as compared to normal controls. It was shown, that overexpression of proteins SOD2 and TXN occurs much more frequently in diffuse tumors than in intestinal ones. A control panel of eleven proteins overexpressed in stomach tumors has been selected based on the data of comparative 2D analysis described in the literature. Bioinformatics search for mRNAs encoding proteins from the control panel in Oncomine database (which contains the results of determination of mRNA transcription level in tumor vs. normal samples) demonstrated the coincidence of proteomic and transcriptomic data for seven out of 11 proteins.

[Ten-year experience with intraoperative radiotherapy]

An analysis of the end results of combined treatment for stage III non-small cell lung cancer, stage III gastric cancer and soft-tissue sarcoma has been carried out. Radical surgery was supplemented with intraoperative radiation therapy (IORT) with a single dose of 10-20 Gy. The radiation source was an original small-size betatron installed in the operating room. IORT did not interfere with wound healing nor did it involve increase in postoperative lethality. The 5-year survival rates for lung cancer patients who received IORT or surgery alone were 34.1 and 24.4%, respectively. The same indices for gastric cancer in IORT patients were 34.2% while in surgical cases--21.7%. Two-year non-relapse survival in patients with soft-tissue sarcomas showed a rise due to reduced recurrence incidence in irradiated areas.