Abstract: Objective To evaluate the influence and significance of Pingyangmycin chemotherapy on the c-myc and Ras-P21 protein expression in penile cancer.Methods A total of 100 penile squamous cell carcinoma cases was retrospectively studied and divided into two groups.Data were obtained from 1995 to 2005.In the chemotherapy group,50 cases of patients were selected to perform preoperative chemotherapy before surgery.The patients were treated by Pingyangmycin.After 7 times of medication,partial excision of penis plus improved inguinal lymph node dissection was performed.In the control group,50 cases of patients were selected for partial excision of penis plus improved inguinal lymph node dissection directly without any pre-operative chemotherapy.All pathology specimens were detected of c-myc and Ras-P21 protein expression by immunohistochemical staining assay.The χ² test was used for the statistical analysis.Results In chemotherapy group,the positive expression rates of c-myc and Ras-P21 were 30%,27%,respectively.However,in control group,the positive expression rate of c-myc,Ras-P21 were 52%,48%,respectively.By the χ² test,the expressive differences of c-myc,Ras-P21 positive expression rate between chemotherapy group and control group were all significant(P<0.05).Conclusion The protein expressions of c-myc and Ras-P21 is significantly decreased in the tissue of Pingyangmycin chemotherapy of penile cancer.