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

<b>Background/Objectives</b>: 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. <b>Methods</b>: 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. <b>Results</b>: The most frequently mutated genes were <i>TP53</i> (61.5%) and <i>KRAS</i>. The median TMB was 4.0 mut/Mb and was significantly lower in stage IV tumors. Significant co-occurrence was observed between <i>KRAS</i> and <i>TP53</i> mutations, as well as between <i>APC</i> and <i>KRAS</i> mutations, which were particularly characteristic of colorectal cancer. <i>KRAS</i> 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. <b>Conclusions</b>: 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.