The lack of p16 expression has been shown in cultured melanoma cells, howev
er contradictory evidence for p16 expression in melanoma tissues exist. Ult
raviolet (UV) C and UVB have been shown to affect p16 expression, which imp
airs cell cycle regulation in vitro and in vivo, In this study, p16/CDKN2A
gene expression was determined by reverse transcription polymerase chain re
action in seven skin cancer patients, in one dysplastic nevus patient and i
n seven healthy individuals, prior to UVB exposure and at various times aft
er application of one minimal erythema dose (MED). Five of the seven skin c
ancer patients showed a down-regulation of p16/ CDKN2A expression after UVB
exposure, while controls remained unaltered. The UVB-induced decline of p1
6/ CDKN2A in skin cancer patients might offer new insights into photocarcin
ogenesis. The putative sequence of events could start with a down-regulatio
n of p16/CDKN2A expression, which would lead to impaired cell cycle regulat
ion. Altered expression patterns of p16/CDKN2A following UVB exposure could
be of value for identifying people with an increased risk of UV-induced sk
in cancer.