PROLIFERATION AND APOPTOSIS WITHIN JUVENILE CAPILLARY HEMANGIOMAS

Capillary hemangiomas (CH) are benign vascular neoplasms of childhood that undergo a natural course of postnatal growth followed by spontane ous involution and often complete regression. There are currently no e stablished standards for the identification of the growth phase of CH. We retrospectively examined 24 CH specimens for staining with MIB1, a monoclonal antibody directed at the same proliferation-related antige n as Ki-67, and antibody to bcl-2, a protooncogene product associated with inhibition of cellular apoptosis, and correlated these findings w ith the growth phase. All lesions demonstrated more positivity with MI B1 than with bcl-2, with more prominent staining in interstitial cells and an inverse correlation with increasing age. When calculations wer e adjusted for vascular lumina predominance, staining similarly decrea sed but at a later age. Our study supports interstitial cell-predomina nt proliferation within CH. In addition, bcl-2 expression was demonstr ated, also interstitially predominant, and showed a decrease with agin g, suggesting that programmed cellular death is involved in the growth regulation of these lesions and that regression is associated with ch anges in both proliferation and apoptosis. Last, both proliferation an d bcl-2 expression showed a marked decrease later in more vascular cha nnel-predominant lesions, possibly suggesting that such lesions underg o longer periods of growth before entering the involutional phase.