The interplay of cell cycle and DNA repair gene alterations in upper tract urothelial carcinoma: predictive and prognostic implications.

Upper tract urothelial carcinoma (UTUC) is rare but can occur sporadically outside the context of Lynch syndrome. In these cases, knowing whether non-mismatch repair (MMR), DNA damage response and repair (DDR), and cell cycle gene alterations may predict responses to chemotherapy or immunotherapy and survival is of clinical importance. This study examined the germline and somatic mutational landscape of two UTUC patients with differential responses to programmed death 1 (PD-1)/PD-ligand 1 (PD-L1) immune checkpoint inhibitors and queried three independent UTUC cohort studies for co-occurrence of key cell cycle and DDR genes, as well as for their associations with overall survival (OS). TP53 and RB1 emerged as potential determinants of shorter OS in UTUC cohort patients, regardless of concurrent DDR alterations, and if prospectively assessed in larger studies they might also explain resistance to PD-1/PD-L1 blockade despite PD-L1 expression.