Thymidine Phosphorylase Drives SARS-CoV-2 Spike Protein-Induced Lung Tumorigenesis.

Rationale and Objectives: COVID-19 survivors exhibit increased interstitial lung fibrosis, a known risk factor for lung cancer. We investigated whether SARS-CoV-2 Spike protein (SP)-induced lung injury and elevated thymidine phosphorylase (TYMP) promote lung tumorigenesis. Methods: A TriNetX retrospective cohort analysis was combined with mechanistic studies in K18-hACE2 Results: Propensity score-matched TriNetX cohorts demonstrated an increased lung cancer risk after COVID-19, particularly among current smokers (n = 166,807; RR 1.22; HR 1.50; P < .001). In mice, SP induced acute lung injury, neutrophil infiltration, and microthrombi, which were reduced in TYMP-deficient mice. SP markedly increased lung tumor incidence and aggressiveness, whereas TYMP deficiency reduced tumor formation from 50% to 18% of lung lobes. SP-induced STAT3 upregulation and collagen deposition were significantly attenuated in K18-hACE2 Conclusions: SARS-CoV-2 SP drives lung injury, fibrosis, and tumorigenesis through a TYMP-dependent mechanism involving STAT3 signaling and inflammatory microenvironment remodeling. COVID-19 significantly increases lung cancer risk, especially in current smokers.TYMP represents a potential therapeutic target to mitigate long-term pulmonary consequences of COVID-19.