Integrin Expression and Apoptotic Cells in Dermal Melanocytic Tumors

Hong, Moon Hee; Chung, Byound Soo

Abstract

BACKGROUND: Many mammals normally have a population of dermal melanocytes but these are not found in man, In humans, persistent dermal melanocytes can occur in the Mongolian spot, the nevus of Ota, and the blue nevus. Mongolian spot develops in the fetal or neonatal time and disapperars almost invariably during childhood. In contrast, nevus of Ota and blue nevus are not usually present at birth and persists in adult life. Recently, it was established that apoptosis can be involved in the development of melanocytes. The integrins mediate cell-cell and cell-matrix interactions, and apoptosis can be induced by disruption of cell-matrix interactions.
OBJECTIVE
The purpose of this study was to investigate the expression of integrins (a2, a3, ar) and in situ detection of fragmented DNA in Mongolian spot, nevus of Ota, and blue nevus.
METHODS
Formalin-fixed and paraffin-embedded tissues from 8 cases of Monglian spot, 5 cases of nevus of Ota, and 4 cases of blue nevus were immunolabelled with monoclonal antibodies TM directed against az, ay, and av integrin, and stained with ApopTag in situ using an Apoptosis Detection kit. The cases of Mongolian spot were divided into two groups in which group A represented the the cases of more than 45 melanocytes and group B represented the cases of less than 10 melanocytes in a tissue section of 4-mm taken from punch biopsy specimens.
RESULTS
Blue nevi showed az and e integrin expressions in dermal melanocytes and weak to negative staining of g v integrin in comparison with all positive expressions of a z, a s, and g y integrin in A group-Mongolian spots and nevi of Ota. The B group-Mongo]ian spots showed the continuous expressions of a z and a y integrin with negative expressions of a v integrin. The ApopTag kit staining was all negative in the Mongolian spots, nevi of Ota, and blue nevi.
CONCLUSION
Our results support the view that dermal melanocytic tumors, such as the Mongolian spot, the nevus of Ota, and the blue nevus, might be induced by the disturbance or inhibition of the apoptotic process of the melanocytes, and that the spontaneous disappearance of the Mongolian spot may not be related to the apoptosis.