Detection of telomerase activity in psoriasis lesional skin and correlatonwith Ki-67 expression and suppression by retinoic acid

Telomerase activity is usually detected in most tumor tissues but not in no rmal tissues. Recently, there is increasing evidence that telomerase activi ty is associated with cell proliferation without malignancy, whereas there is little information about telomerase activity and its relationship with c ell proliferation in chronic hyperproliferative skin diseases. Thus, we stu died telomerase activity in skins from 10 patients with psoriasis and compa red telomerase activity with the expression of Ki-67, a proliferation marke r, using immunohistochemical staining. The effect of retinoic acid on the t elomerase activity in HaCaT cells was also evaluated. Telomerase activity w as detected in 7 (70%) of 10 lesional skins of psoriasis and none of the no nlesional skin. Telomerase activity in lesional skin was significantly asso ciated with Ki-67 labelling index. Retinoic acid treatment on HaCaT cells I nhibited telomerase activity, which correlated with inhibition of cell prol iferation by the agent. The results of our study represent another example that shows telomerase activity correlates with cellular proliferation. Furt her studies on the regulation of the telomerase are needed to understand th e cellular factors involved in controlling telomerase activity.