CASP3 and nasopharyngeal carcinoma: The data from DNA laddering assay (Figures 3(a) and 3(b)) and immunoblotting assay (Figures 3(c) and 3(d)) show that, in both NPC cell lines, the control groups slightly showed DNA ladder formation and the expression of cleaved caspase-3 and PARP proteins, which could be due to the serum starvation.