Are keloids really "gli-loids"?: High-level expression of gli-1 oncogene in keloids

Background: Keloids are a common lesion arising from Sites of previous trau ma and are a considerable source of morbidity because of continued growth o f lesions, and physical appearance. They consist of mesenchymal cells embed ded in a stroma of disordered collagen matrix. Clinically, keloids are dist inguished from scars in that keloids demonstrate continued growth over the borders of the original injury. Keloids appear with increased frequency, in patients of African and Asian descent. Currently, no entirely satisfactory , method of treatment exists for these lesions. Recently, a patient who was enrolled in a clinical trial of topical tacrolimus for atopic dermatitis a pplied this drug to a keloid and noted clearing. Objective: Based on this clinical observation and the observation that rapa mycin, a chemically similar compound to tacrolimus, is known to inhibit sig naling from the gli-1 oncogene, we examined keloids and scars for expressio n of Gli-1 protein. Methods: Skin sections from keloids and scars were examined by immunohistoc hemical staining for gli-1. To further confirm the presence of gli-1 expres sion in keloids, reverse transcriptase-polymerase chain reaction was carrie d out. Results: Expression of gli-1 was strongly elevated in keloids compared with scars. Conclusion: These results provide a rationale for the treatment of keloids with topical rapamycin analogs, including tacrolimus. Clinical trials of to pical tacrolimus ire warranted.