E2F1 and tuberculosis: Expectably, we found overexpression of not only transcriptional factor genes (E2F1 and P53) but also downstream genes (GADD45, BAX, BCL-2, BIM, CASP 7, CASP 8, CASP 9, and CASP 3) in TB-treated A549 cells, suggesting a P53 pathway-mediated apoptosis induced by TB (Figure 6).