bcl-2 expression in pilomatricoma

Pilomatricoma is a distinctive tumor characterized by a dual population of proliferating basophilic cells and diagnostic shadow cells, believed to arise from the hair matrix. The normal hair matrix undergoes defined cycles of growth (anagen), regression (catagen), and resting (telogen) that are regulated by programmed cell death (apoptosis). bcl-2 is a proto-oncogene that helps to suppress apoptosis in both benign and malignant tumors. In addition, both apoptosis and bel-2 are critical factors in normal hair follicle development. In order to clarify the role of bcl-1, we used immunohistochemical means to study 10 cases of histologically proven pilomatricoma for bcl-2 expression. The study design included both positive and negative controls. All of the pilomatricomas in our series were strongly decorated by bcl-2 immunostaining. Based on our findings of increased bcl-2 staining, we concluded that the faulty suppression of apoptosis contributes to the pathogenesis of pilomatricoma.