# Genetic Landscape of Solid Malignant Tumors in a Russian Cohort of Patients

## TL;DR

This study analyzed the genetic profiles of solid tumors in Russian cancer patients and found actionable mutations that could guide personalized treatments.

## Contribution

The study provides the first comprehensive genomic profiling data for solid tumors in a Russian patient cohort.

## Key findings

- TP53 and KRAS were the most frequently mutated genes in the cohort.
- KRAS mutations were associated with higher PD-L1 expression in lung cancer patients.
- 44% of patients had actionable mutations for approved therapies, and 36% for off-label therapies.

## Abstract

Background/Objectives: Comprehensive genomic profiling (CGP) is a cornerstone of personalized oncology. However, large-scale, systematic data on the somatic mutation spectrum in Russian cancer patients are scarce. This study aimed to characterize the genomic landscape and assess the potential for matched therapy in a Russian cohort of patients with solid tumors. Methods: This retrospective study included 204 patients with various solid tumors. CGP was performed using the FoundationOne®CDx (FFPE tissue) and FoundationOne®Liquid CDx (cfDNA) platforms. The analysis assessed single-nucleotide variants, indels, copy number alterations, gene fusions, tumor mutational burden (TMB), microsatellite instability (MSI), and PD-L1 expression. Results: The most frequently mutated genes were TP53 (61.5%) and KRAS. The median TMB was 4.0 mut/Mb and was significantly lower in stage IV tumors. Significant co-occurrence was observed between KRAS and TP53 mutations, as well as between APC and KRAS mutations, which were particularly characteristic of colorectal cancer. KRAS mutations were associated with higher combined positive score (CPS) values in cases with lung cancer. Based on the CGP results, 44% of patients had findings that supported the use of an approved matched targeted therapy or immunotherapy for their tumor type. An additional 36% of patients had alterations indicating potential benefit from off-label targeted therapy. Conclusions: This study reveals the distinct genomic characteristics of solid tumors in a Russian cohort and confirms the high clinical utility of CGP for identifying actionable targets. Implementing CGP early in the diagnostic process is a necessary step towards realizing personalized treatment strategies for cancer patients.