The Expression of c-Jun and JunB in Various Skin Tumors

Ko, Bum Joon; Cho, Moon Kyun; Park, Young Lip; Lee, Jong Suk; Lee, Jeung Hoon; Whang, Kyu Uang

Abstract

BACKGROUND
c-Jun along with JunB, JunD, and the Fos group proteins comprise the core members of the activator protein 1 (AP1) family of transcription factors. Recently, many studies have demonstrated the key roles of AP1 in regulating a wide spectrum of biological processes, including tumorigenesis. We therefore hypothesized that c-Jun and JunB influence the differentiation and malignant change of various skin tumors.
OBJECTIVE
We measured the expression levels of c-Jun and JunB in different skin tumors.
METHODS
The expressions of c-Jun and JunB were examined by performing the immunohistochemical staining of 55 specimens of skin tumors, including 13 cases of seborrheic keratosis, 4 cases of keratoacanthoma, 9 cases of actinic keratosis, 4 cases of Bowen's disease, 4 cases of basal cell carcinoma, 16 cases of squamous cell carcinoma, and 5 cases of malignant melanoma.
RESULTS
Immunohistochemical analysis of the skin tumor tissue samples revealed a significantly higher expression of c-Jun in malignant skin tumors (basal cell carcinoma, squamous cell carcinoma, malignant melanoma) than in benign (seborrheic keratosis, keratoacanthoma) or premalignant skin tumors (actinic keratosis, Bowen's disease). The expression of JunB, however, was significantly lower in malignant skin tumors than in benign skin tumors.
CONCLUSION
These findings showed that c-Jun has a positive association with skin malignancies, while JunB has a negative association with skin malignancies. The role of AP1 as key regulators of cell proliferation and epidermal tumor progression is suggested.