#2918 Genetic background of kidney graft cancer

Abstract Background and Aims Renal cell carcinoma (RCC) is one of the most prevalent cancer in kidney transplant recipient (KTR). Majority of RCC occurs in native kidney as opposed to kidney graft. The genetic background of RCC in native kidneys has been determined implicating the clinical importance. Method This single-center cohort study aimed to identify genetic background of kidney graft RCC and outcome in KTR who underwent single kidney transplantation between January 2000 and December 2020 and manifested kidney graft RCC. Genetic analysis (NGS) from peripheral blood-derived genomic DNA (gDNA) was performed in both the recipient and donor using cancer-predisposition panel CZECANCA (CZEch CAncer paNel for Clinical Application). Results The calculated incidence of kidney graft RCC was 0.43%. Of the eighteen KTR with manifested kidney graft RCC, fifteen KTR and donors underwent NGS. The average patient age at transplantation was 50.3 years (median 54; 5-67 years) and 66 years (median 66; 24-79 years) at the diagnosis of kidney graft RCC. The mean donor age at transplantation was 39.7 years (median 42; 7-68 years) and graft age at kidney graft RCC diagnosis 50.2 years (median 46; 20-83 years). The mean follow-up after RCC diagnosis was 47 months (median 39.1; 0-112 months). The most prevalent was papillary RCC (n=8) followed by clear cell RCC (n=6) and renal pelvis urothelial RCC (n=1). Thirteen RCC were low stage (pT1a/b) disease, one was pT3 and one was unknown stage. Majority of RCC were higher graded. No cancer-predisposition gene was found in KTR or his donor. Conclusion Kidney graft RCC is very rare. NGS cancer-predisposition panel CZECANCA has not detected any genetic predisposition for kidney graft RCC. Further research is needed to assess clinical relevance of genetic testing for cancer risk in KTR.