In addition, further animal experiments are needed to explore the functional role of PTTG1 in lung adenocarcinoma, as well as to detect the specific effects of PTTG1 on tryptophan metabolism by methods such as liquid chromatography-tandem mass spectrometry (LC-MS/MS), which could help to provide stronger clues to guide the clinical application. Here, PTTG1 is linked to lung adenocarcinoma.