A fundamental aspect of cancer development is cancer cell proliferation.Seeking for chemical agents that can interfere with cancer cell growth has been of great interest over the years.In our study,we found that a benzoxazine derivative,(6-tert-butyl-3,4-dihydro-2Hbenzo[b][1,4]oxazin-3-yl)methanol(TBM),could inhibit cell growth and caused significant cell cycle arrest in pulmonary adenocarcinoma A549 and H460 cells with wild-type p53,while not affecting the cell cycle distribution in p53-deleted H1299 lung adenocarcinoma cells.Since P53 plays an important role in regulating cell cycle progression,we analyzed the protein level of p53 by Weste blot,and detected a significant elevation of p53level after TBM treatment in A549 and H460 cells.The data suggested that TBM might specifically inhibit the proliferation of p53 wild-type lung adenocarcinoma cells through a p53-dependent cell cycle control pathway.More interestingly,results indicated that TBM might serve as a useful tool for studying the molecular mechanisms of lung cancer cell growth and cell cycle control,especially for the biologic process regulated by P53.