Expression of Cyclin D1 and Ki-67 in Squamous Cell Carcinoma of the Penis

Abstract

Background: Cyclin D1 plays an important role in regulating the progression of cells through the G1-phase of the cell cycle. The aim of the study was to investigate the expression of cyclin D1 and Ki-67 in squamous cell carcinomas (SCC) and in some premalignant lesions of the penis and to correlate it with clinicopathological parameters and patient survival. Materials and Methods: Formalin-fixed paraffin-embedded tissues from 21 SCC, 7 lichen sclerosus, 5 condyloma acuminatum and 2 erythoplasia of Queyrat were stained by immunohistochemistry for cyclin D1 and Ki-67. Results: Cyclin D1-positive nuclear staining was overexpressed in 13/21 SCC (61.9%) and in one case of erythoplasia of Queyrat. Strong reactivity for Ki-67 was found in 16 (76.2%) SCC, in 3 condyloma acuminatum and in one case of erythoplasia of Queyrat. A tendency for an association between cyclin D1 expression and tumour differentiation (p=0.07) but not the level of tumour invasion (p=0.50) was found. The Ki-67 expression was notably increased with the advance of tumour grade, but the difference did not reach a statistically significant level (p=0.46). A slight tendency towards a relationship between Ki-67 and cyclin D1 protein expression was observed (p=0.32). Two patients relapsed and one died from the disease over a median follow-up period of 4.6 years (range 0.1-10.3 years). Conclusion: Ki-67 antibody and cyclin D1 overexpression seem to parallel each other, supporting the concept that cyclin D1 serves as a cell cycle activator. Cyclin D1 overexpression may be used as a prognostic factor of poor outcome in penile carcinoma.