TK1 and lung cancer: Given that AK4 has been shown to worsen lung cancer patient outcomes by suppressing levels of activating transctiption factor 3 (ATF3) [40], a transcriptional regulator of TK1 [74], our finding that TK1 promotes LUAD tumor progression within the larger AK4 co-expression network may expand on the mechanistic link between AK4, ATF3, and TK1 in the context of LUAD.