RESUMEN
<p><b>OBJECTIVE</b>To investigate the expression and distribution of mast cell tryptase (MCT) in scar, and to discuss the different MCT gene expression in keloid, hypertrophic scar and normal skin.</p><p><b>METHODS</b>20 samples of keloid, 20 samples of hypertrophic scar and 20 samples of normal skin were collected. The distribution of MCT was investigated by immunofluorescence histochemistry, and the MCT mRNA expression was detected by Relative Quantification real-time fluorescent PCR.</p><p><b>RESULTS</b>MCT gene was mainly located in the collagen fiber bundles of the scar, especially in the superficial layer of scar. MCT mRNA expression was significantly higher in keloid than that in hypertrophic scar and normal skin (P < 0.01). Averagely, the MCT gene expression in keloid was 2.5 times and 5.4 times of that in hypertrophic scar and normal skin.</p><p><b>CONCLUSIONS</b>MCT gene may play a role in the pathogenesis of scar.</p>