In the present study, EGCg was demonstrated to markedly inhibit cell proliferation at concentrations between 25 and 100 μM (Fig. 3), and decrease Bcl‑xL mRNA expression under the same conditions at 100 μM (Fig. 4) in A549 cells. EGCg has been reported to inhibit the activation of NF‑κB (14), and the activation of NF‑κB leads to the inhibition of apoptosis. NF‑κB is a heterodimer consisting of two proteins, p65 and p50. In unstimulated cells, NF‑κB is located in the cytoplasm and is bound to IκBα and IκBb, which prevents the molecule from entering the nucleus. External stimuli modulate signal transduction pathways leading to IκB phosphorylation, causing its rapid degradation by proteasomes. The release of NF‑κB from IκB results in translocation to the nucleus, where NF‑κB binds to a specific sequence in the promoter regions of target genes of antiapoptotic proteins, including Bcl‑xL. Therefore, the results of the present study indicate that EGCg reduces the expression of the death‑inhibiting gene, Bcl‑xL, consequently inducing apoptosis in A549 cells.