Determination of β-galactosidase-associated senescence of HeLa, SiHa and HaCaT cells after in vitro treatment with PTX or CIS either alone or in combinations. 24 hours later the cells were harvested and senescence was determined by histochemistry using senescence detection kit (BioVision Mountain View, CA, USA). The results represent the mean ± SD of three independent experiments carried out in triplicate. Statistical analysis, Student's t test. (*) P < 0.001 vs CTL. (♦) P < 0.001 vs CIS.