%0 Journal Article %T Progressive Extracellular Matrix Disorganization in Chemically Induced Murine Oral Squamous Cell Carcinoma %A B. Fuentes %A J. Duaso %A D. Droguett %A C. Castillo %A W. Donoso %A C. Rivera %A B. Venegas %A U. Kemmerling %J ISRN Pathology %D 2012 %R 10.5402/2012/359421 %X Introduction. Oral squamous cell carcinoma (OSCC) is one of the ten most common cancers affecting the human population. Tumor pathogenesis implies a multistep process in which cells acquire features that enable them to become tumorigenic and ultimately malignant. The process of OSCC carcinogenesis can be reproduced in animal models, the OSCC induction with 4-nitroquinoline-1-oxide (4NQO) in mice is a widely used tool for studying tumor pathogenesis. Objective. The aim of the present study was to determine the progressive changes in basal lamina and connective tissue remodeling during 4NQO-induced OSCC carcinogenesis. Material and Methods. Samples were classified according to ¡°International Histological Classification of tumors¡± in mild, moderate, and severe dysplasia and invasive carcinoma. Five samples of each pathologic entity and control healthy tongues were used. Immunohistochemical analysis of collagen IV as well as histochemical analysis of glycosylated molecules (PAS) and collagen I (Picro Sirius red) were performed. Results. During experimental-induced carcinogenesis by 4NQO a progressive basal lamina destruction and collagen I disorganization in adjacent connective tissue can be observed. Conclusion. Our results confirm previous studies that show alterations in extracellular matrix (ECM) in malignant lesions, validating the experimental carcinogenesis induced by 4NQO. 1. Introduction Squamous cell carcinoma of the oral cavity (OSCC) is one of the ten most common tumors affecting the human population [1]. Continued population growth and aging have contributed to the increase in this type of pathology, making it an important public health problem. It starts as an epithelial dysplasia and is characterized by an altered proliferation of squamous dysplastic cells of the epithelial surface stratum [2]. It progresses to degrade the subepithelial basement membrane [2, 3], generating a local destruction and distant invasion through the process of metastasis [3¨C5]. Local invasion of the underlying connective tissue occurs through islets and cords of epithelial cells [3, 6]. Interaction between tumor cells and extracellular matrix (ECM) components is essential for tumor growth [7, 8] and for the onset of cell spreading and subsequent metastatic activity [9]. The basal lamina, a physicochemical barrier to tumor invasion [10], plays a fundamental role in the processes described above. It is a highly specialized structure, consisting of a set of molecules with different sensitivity to proteolytic degradation. Its components are synthesized and secreted by %U http://www.hindawi.com/journals/isrn.pathology/2012/359421/