Objective The aim of this study was to understand the role of specific markers of stem cells Oct-4 expression in the development of human epidermal non-melanoma cutaneous tumors.Methods The paraffin-embedded samples were retrieved from files of pathology department at our hospital,including 20 cases of skin squamous cell carcinomas (SCC),20 cases of basal cell carcinomas (BCC),20 cases of seborrhoeic keratosis (SK) and 20 cases of normal skin (from head,face,trunk,extremities).The expression of Oct-4 and PCNA were observed by immunohistochemical staining technique.Results Oct-4 protein was abnormally increased in SCC and BCC comparel to normal skin and SK ( P ＜0.05 ).However there were no significant difference of Oct-4 protein expression between SCC and BCC ( P ＞0.05).There were also no significantly different Oct-4 protein expression between Sk and the normal skin ( P ＞ 0.05 ),and no significantly different Oct-4 protein expression between SK and BCC( P ＞0.05 ).PCNA protein was abnormally increased in SCC and BCC compared to normal skin and SK ( P ＜0.01 ).There were significantly different PCNA protein expression between SCC and BCC( P ＜0.05).There were also significantly different PCNA protein expression between SK and the normal skin ( P ＜ 0.05 ).However there were no significant difference of PCNA protein expression between SK and BCC ( P ＞ 0.05 ).There were positive correlation between the expression intensity of Oct-4 and PCNA in SCC and BCC.Conclusions The abnormal expression of Oct-4 may have an important role in the development of BCC and SCC.Positive Oct-4 expression cells may be the tumor stem cell in SCC and BCC.There were positive correlation between the expression intensity of Oct-4 and PCNA in SCC and BCC.The over expression Oct-4 in BCC and SCC may play an important role in proliferation of tumor.