MTT assay was performed to monitor cell proliferation in PDCD5 overexpressing A431 cells and its control cells. The cells were splitted at the similar density for the PDCD5 overexpressing cells and the control cells. Cell growth was monitored at multiple time points, including 12, 24, 48, 72 and 96 h. From 72 h, the cell viability was significantly lower in the PDCD5 overexpressing cells compared with the control cells. **P<0.01. Control, empty vector-transfected A431 cells; PDCD5, PDCD5 overexpressing A431 cells.