The DNA content, PCNA and P53 expression in vulva lichen sclerosus and their relationship with cell proliferation were studied.The expression of P53 gene protein and proliferating cell nuclear antigen (PCNA) were detected by immunohistochem. technique and size and DNA content of the basal cell nuclei were measured by an automatic color image anal. system in 20 patients with vulva lichen sclerosus and 10 specimens of normal vulva skin.The result showed that compared with normal skin, in lichen sclerosus, PCNA expression was higher, but had no statistically significant difference (P>0.05); P53 expression was higher; the size of the basal cell nuclei and the DNA content were decreased (P<0.05).The most pos. expression showed in the prickle and granular cells.The vulva lichen sclerosis were related to abnormal cell proliferation.