Immunohistochemical Expression of Integrins and bcl - 2 in Melanocytic Nevi and malignant Melanomas

Park, Jong Jun; Chung, Byoung Soo

Abstract

BACKGROUND
The integrins comprise a family of transmembrane glycoproteins which mediate cell-cell and cell-matr ix intera ctions, and the bcl-2 oncogene is involved in tumorigenesis by blocking apoptosis. Typical acquired melanocytic nevi appear to follow a life cycle characterized by active growth, maturation, and progressive involution. In contrast, congenital rnelanocytic nevi have a different course and prcgnosis with potential for development of melanoma, and metastatic spread is very common in malignant melanoma.
Objective
. We investigated the expression of integrins (a2,a3,a) and bcl-2 in congenital and acquired rnelanocytic nevi, and malignant, melanomas by immunohistochemical technique.
Methods
. Formalin-fixed and paraffin-embedded tissues from 7 compound nevi, 7 intradermal nevi, 5 congenital melanocytic nevi, and 5 malignant melanomas were immunolabeled with monoclonal antibodies directed against a2, a3,and a integrin, and bcl-2 protein.
RESULTS
All acquired and congenital melanocytic nevi showed a uniform staining for a2, a3, a and bcl-2. In 3 compound nevi which the nevus cells lie mainly within the upper dermis, the nevus cells in the papillary dermis showed weak to negative a expression. Within neurotized are as of intradermal nevus, bcl-2 and a expression became weaker and totally absent. All 5 malig- nant melanomas exhibited strong a2, a3, a, and bcl-2 expression. However, the tumor cells in the lower advancing border failed to express a integrin in 3 of 5 malignant, melanomas. In most malignant melanomas, there was variable intensity of staining for bcl-2 in different areas of the tumor.
Conclusion
. These findings suggest that the integrins and bcl-2 may be involved in active growth, maturation, and progressive involution of the melanocytic nevi, and seem to be related to metastasis and tumorigenesis of the malignant melanoma.