Expression of matrix metalloproteinases (MMP-2 and MMP-9) in laryngeal papillomas and laryngeal cancer

Abstract

The matrix metalloproteinases (MMP) are a family of proteolytic zinc-containing enzymes, which are responsible to degrade extracellular matrix components and play an important role in the physiological and pathological remodelling of tissues. They role in the development of malignant neoplasia is under investigation. Purpose: To define the expression of MMP-2 and MMP-9 in the tissue from laryngeal papillomas (LP) and laryngeal carcinoma (LC). Methods: The immunohistochemical expression of MMP-2 and MMP-9 was investigated in specimens taken by endolaryngeal microsurgery from laryngeal papillomas (n = 26) and laryngectomy specimens (n = 30) from invasive laryngeal carcinoma. Expression of MMP-2 and MMP-9 was graded on a semiquantitative scale ranging from 0 to 3 point in epithelium and stroma cells by two investigators; thus, the final score ranged from 0 to 6. The nonparametric Kruskal–Wallis test was used for statistical analysis. Results: Epithelial cells of LP and LC demonstrated significantly (P\0.05) higher MMP-9 expression in comparison to MMP-2. Expression of MMP-2 did not differ between epithelial cells from LP and LC, while its expression was much higher in stroma cells from LC in comparison to LP (P\0.001). The epithelial expression of MMP-9 was statistically significantly higher in LC specimens in comparison to LP (P\0.05). MMP-9 positive epithelial cells were located only in basal layer of LC. Conclusion: Expression of MMP-2 in stroma and MMP-9 in epithelial cells was significantly higher in laryngeal carcinoma specimens than in papillomas. It indicates necessity of further investigations to define function of MMP in morphogenesis of premalignant and malignant laryngeal lesions.