[Correlation of tumor budding with DNA mismatch repair system and PD-L1-status in gastric cancer]

To detect the presence or absence of correlations between the degree of tumor budding (TB) and pMMR/dMMR (proficient Mismatch Repair System/deficient Mismatch Repair System) and PD-L1 status in gastric cancer (GC).

Surgical material from 173 patients with verified gastric cancer of the tubular histological subtype, where the invasive edge of the carcinoma was examined, tumor budding were identified and counted by three methods: H. Ueno, L. Wang and, E. Karamitopolou. Patients with GC were divided into two groups - with low and high degree of tumor budding (LG-TB and HG-TB). dMMR and PD-L1 status were identified by immunohistochemical staining.

Using the H. Ueno method, a predominance of low-grade TB was found in the group of dMMR carcinomas (90.5% of dMMR cases were associated with LG-TB, p=0.035). According to the L. Wang method, 85.7% of dMMR cases were identified that were associated with LG-TB, p=0.028. According to the E. Karamitopolou method, it was found that 76.2% of dMMR cases were associated with LG-TB, p=0.106. When analyzing the relationship between tumor budding and PD-L1 expression, no statistically significant differences were found (p>0.05).

The low degree of tumor budding, estimated by the methods of H. Ueno and L. Wang, correlates with the dMMR status of tumor tissue. No statistically significant association was found when counting tumor budding using the E. Karamitopolou method. The degree of tumor budding determined by any of the methods does not correlate with the PD-L1 status of GC.