Mast cells and matrix metalloproteinase 9 expression in actinic cheilitis and lip squamous cell carcinoma

Objectives The aim of this study was to evaluate mast cell (MC) density and migration and their association with matrix metalloproteinase (MMP) 9 expression in squamous cell carcinoma (SCC) and actinic cheilitis (AC). Study design Tryptase, c-Kit, and MMP-9 expression was evaluated in 20 cases of SCC, 20 cases of AC, and 7 cases of normal lip (control samples) by immunohistochemistry techniques. Results Tryptase+ and c-Kit+ MC densities were significantly higher in SCCs than in ACs and control samples (P < .001). However, no significant difference was found when comparing tryptase+ and c-Kit+ MC densities between ACs and control samples (P values .185 and .516, respectively). MMP-9 was strongly expressed in SCCs and moderately expressed in ACs and control samples. A highly significant association was found between tryptase+ MC density and the expression of MMP-9 (P < .001). Conclusions The increase in MC density associated with the strong expression of MMP-9 may favor SCC progression.