Cell proliferation assay. The proliferation rates of non-irradiated control (CON) cells and non-irradiated p21-overexpressing (p21+) cells were significantly higher than UVB-irradiated cells. The proliferation rates of all UVB-exposed groups (UVB-CON, UVB-p21+, and UVB-p21– cells) were significantly suppressed. Proliferation of UVB-p21+ cells was more obviously suppressed compared to those of both UVB-p21– and UVB-CON cells, but there are no significant differences in proliferation between p21– and UVB-p21– cells. * p<0.05 vs. CON, #
p<0.05 vs. p21+, @
p<0.05 vs. p21–, &
p<0.05 vs. UVB-CON.