To determine if Tat-Fhit 7-13 peptide could mimic the effects of the wild-type Fhit protein on A549 and Calu-2 lung cancer cell lines, cells were treated with a single administration of 50, 100 or 150 μM Fhit Tat-7-13 peptide and 24 h later cell death was assessed by flow cytometry. The gene discussed is TAT; the disease is lung cancer.