18, 19 and 20 In addition, some studies have also identified MCs derived from tryptase and chymase as powerful MMP activators.21 and 22 The literature agrees with the role of the stromal microenvironment in tumoral progression. Various experiments show evidence of cooperation or synergy between neoplasic and stromal

cells in MMP production.23 and 24 The purpose of the present study was to evaluate MC density and migration and their association to MMP-9 expression in AC and lip SCC to better understand the role of MCs and MMP-9 in these lesions. We selected 20 cases of AC, 20 cases of SCC, and 7 cases of normal lip (used as control), all embedded in paraffin, from the files of the Pathologic Anatomy Service of the Oral Pathology Course, Dentistry Program, Federal University of Rio Grande do Norte (UFRN). For standardization purposes, selected cases selleck chemicals were microscopically Selleck NU7441 examined by 2 independent examiners through the review of histologic sections stained with hematoxylin and eosin. Histologic features for AC included epithelial changes (keratosis, hyperkeratosis, hyperplasia, atrophy, acanthosis, ulceration, and dysplasia) and connective tissue alterations (solar elastosis and inflammation).1 and 3

Microscopic features for SCC were analyzed according to the World Health Organization tumor classification.2 The study was approved by the Institutional Review Board at UFRN. Paraffin-embedded tissues were sectioned (3 μm) and extended in glass slides coated with 2% 3-aminopropyltriethoxy-silane (Sigma Chemical Co., St. Louis, MO, USA). Sections were deparaffinized by immersion in xylene, followed by immersion in alcohol with 3% hydrogen peroxide to block endogenous

peroxidase activity, and then washed in Tris-buffered saline solution (TBS; pH 7.4). Antigen retrieval, Etomidate incubation, dilution are shown in Table I. Sections were blocked by incubation with 3% normal goat serum diluted in distilled water at room temperature for 20 minutes. Slides were then incubated with the primary antibodies in a humidified chamber. After washing in TBS, sections were treated with labeled streptavidin-biotin kits (K0690; Dako, Glostrup, Denmark) for tryptase and MMP-9 and with the Envision system (K4001; system-labeled polymer–horseradis peroxidase; DakoCytomation, Carpinteria, CA, USA) for c-Kit. We used 0.03% diaminobenzidine (DAB; Sigma, Chemical Co.) as chromogen, and counterstaining was performed with Mayer hematoxylin. Positive control samples for tryptase, c-Kit, and MMP-9 were, respectively, sections of lung, gastrointestinal stromal tumor, and liver. As negative control subjects, samples were treated as above, except that the primary antibody was replaced by a solution of bovine serum albumin in phosphate-buffered saline solution.