[Predictors of therapeutic efficacy of immune response checkpoint inhibitors in clear cell renal cell carcinoma].

Immunotherapy in oncologic diseases involves the use of drugs which stimulate the immune system and indirectly suppress tumor cells growth. These agents have expanded the treatment options for cancer patients. Despite the impressive success achieved in the development of immune checkpoint inhibitors (ICIs) and subsequent approval in a broader spectrum of malignant tumors, most patients are not responded the therapy. Currently available predictive markers of efficacy are nonspecific. However, microRNAs are of particular interest, which regulate gene expression and are involved in the carcinogenesis and therapy resistance. Therefore, it is clear that for the most efficient and cost-effective use of ICIs, it is important to have validated biomarkers that will accurately predict the therapeutic response. The published results on molecular genetic changes in patients with renal cell carcinoma (RCC) were analyzed and summarized in order to determine possible prognostic biomarkers when prescribing ICI therapy.

Exosomal miRNA-146a is downregulated in clear cell renal cell carcinoma patients with severe immune-related adverse events.

Here we report the results of the pilot project of exosomal miRNA expression levels in clear cell renal cell carcinoma (ccRCC) patients with different clinical response to ICIs (nivolumab) and treatment related toxicity. Immune-related adverse events (irAEs) are a major cause of immune checkpoint inhibitors cancellation and therapy failure. Modern studies demonstrate evidence that exosomes are of great importance in the formation of tumor resistance to ICIs drugs and therapy. We performed exosomal miRNA-146a expression analysis using qPCR on 86 ccRCC patients and revealed a statistically significant (p = 0.01) decreased expression level in ccRCC patients with CTCAE grade 3-4 (M±SEM 1.71 ± 0.13) compared to CTCAE grade 0-2 group (M±SEM 2.30 ± 0.24). The expression levels of miRNA-126, miRNA-218 and miRNA-410 did not show statistically significant differences in the comparison groups (p > 0.05). Association analysis of rs2910164 in the miRNA-146a gene demonstrated that CC genotype and C allele carriers had higher risk of developing severe irAEs (p = 0.03, OR = 6.12; p = 0.01, OR = 2.42, respectively) compare with GG and GC carriers. That is the first attempt to identify biomarkers of ICIs treatment efficacy for ccRCC in the Volga-Ural region based on exosomal miRNAs analysis.