TK1 and neoplasm: In the current study, we correlated 18F-FLT uptake at pre- and post-NAT PET, changes in 18F-FLT uptake, and post-NAT histologic variables (percentage tumor necrosis, Ki-67, and thymidine kinase 1 [TK1] expression) with overall survival and disease-specific survival (DSS) in patients previously enrolled in a prospective single-center, single-arm exploratory study.