Introduction: Gastric cancer (GC) is one of the most common cancers in the world. It is a very aggressive and heterogeneous tumor. GC does not cause symptoms, so it is often diagnosed in an advanced stage and associated with poor prognosis. Despite new treatment options, it still remains a therapeutic problem. An important element determining the method of treatment of locally advanced gastric cancer (LAGC) is the assessment of lymph node metastases in preoperative and postoperative imaging and/or histopathological examination.Aim: The assessment of lymphovascular invasion (LVI) in histopathological examination in patients with LAGC after gastrectomy. The groups of patients were divided into patients who received preoperative chemotherapy, patients without preoperative chemotherapy, and all patients. Additionally, we assessed the correlation between the presence of LVI and the number of lymph nodes collected during gastrectomy.Material and method: We collected patients with histologically confirmed GC after gastrectomy. The collected samples were divided into three subgroups: patients with neoadjuvant chemotherapy (NAC), patients without NAC, and all patients. Histopathological examination assessed the presence of LVI infiltration. We then assessed the correlation between the presence of LVI and the presence of lymph node metastasis in GC. Additionally, we assessed the correlation between LVI and the number of lymph nodes evaluated in patients in each group. The statistical analyses were performed using Statistica v13.3 and Microsoft Excel 2021. The significance limit was set at p<0.05.Results:The presence of LVI strongly correlated with node involvement, and the result was statistically significant in all patients and the group of patients treated with NAC. The difference was not statistically significant in the group not treated by NAC. Additionally, we did not observe a correlation between the presence of LVI and the number of metastatic lymph nodes in GC.Summary and Conclusions: The presence of LVI in a patient with GC indicates a high probability of lymph node metastasis, which should translate into therapeutic procedures. Assessment of LVI may help identify potential patients with lymph node metastases, particularly in patients undergoing endoscopic resection without planned lymphadenectomy. It is advisable to expand research on a larger scale in order to establish clear standards in this area.

Introduction: Gastric cancer (GC) is one of the most frequently diagnosed cancers in the world. Although the incidence is decreasing in developed countries, treatment results are still unsatisfactory. The standard treatment for locally advanced gastric cancer (LAGC) is gastrectomy with perioperative chemotherapy. Aim: Assessment of selected microRNAs (miRNAs) in chemoresistance in archival material from LAGC. Material and method: The research group consisted of archival material from 10 patients with LAGC. Histological material from each patient was used from a biopsy performed during gastroscopy and after surgery preceded by 4 cycles of neoadjuvant chemotherapy (NAC) according to the FLOT or FLO regimen. The expression of selected miRNAs was assessed in the tissue material, such as miRNA-21-3p, miRNA-21-5p, miRNA-106a-5p, miRNA-122-3p, miRNA-122-5p, miRNA-143-3p, miRNA-143-5p, miRNA-203a-3p, miRNA-203-5p, miRNA-551b-3p, miRNA-551b-5p and miRNA-574-3p. miRNA expression was assessed by quantitative chain reaction polymerase reverse transcriptase (qRT-PCR). The response to NAC was assessed by computed tomography of the abdomen, chest and histopathology after gastrectomy. The statistical analyses were performed using GraphPad Prism 9.The significance limit was set at p