Precancerous lesions have been studied because of their carcinogenic potential and their association with squamous cell carcinoma (SCC) has been reported. In the tumour microenvironment, the processes of angiogenesis and tissue remodelling are regulated by a family of proteins (Hedgehog) described as being able to modulate epithelial/mesenchymal interactions. The objective of this study was to perform a comparative study of precancerous lesions and SCCs by immunohistochemistry for the presence of Sonic, Gli2, SMO and Patched proteins, members of the Hedgehog pathway. Sixteen cases diagnosed as actinic cheilitis associated with SCC were compared to normal oral mucosa. The sections were subjected to immunohistochemistry and the positively stained cells were counted by morphometric analysis. There was a significant progressive increase in expression of all proteins of the Hedgehog pathway, both in the epithelium and in the connective tissue, when sections of normal mucosa, dysplasia and carcinoma were compared (P < 0.05). Thus, one may suggest that the Hedgehog pathway in tumour transformation influences SCC, and more studies should be conducted to expand the understanding of the role of these proteins in neoplastic transformation.

Introduction: In recent years, cellular biostimulation induced by low-level laser therapy has been widely studied. Among some of the processes stimulated by low-level laser are cell cycle, phenotypic modulation as well as vascular changes, such as vasodilation and neoangiogenesis. The increased number of new blood vessels accelerates inflammation, and also increases wound healing. Neoangiogenesis is still an important process of tissue repair, since it always precedes collagen synthesis and matrix extracellular remodeling. Increasing scientific evidence has shown that photobiomodulation stimulates neoangiogenesis, fibroblast proliferation and collagen biosynthesis. Objective: Review the literature about the effects of low level laser therapy on neoangiogenesis and fibroplasia and describe how these processes occur in the tissue subjected to an injury. Methods and Matereials: The search tool used was the Medline / Pubmed and the following keywords were used: remodeling, wound healing, neoangiogenesis, fibroplasia, laser therapy, low-level laser. Manuscripts published from 1990 to 2017 were selected. Results: Increasing scientific evidence has shown that photobiomodulation stimulates neoangiogenesis, fibroblast proliferation and collagen biosynthesis. Conclusion: Neoangiogenesis always precedes collagen synthesis and matrix extracellular remodeling. However, little is known of the action of laser therapy in the late stages of tissue repair.

OBJECTIVE: The aim of the present study is to conduct a comparative analysis of oral actinic cheilitis and squamous cell carcinomas by immunohistochemical analysis. METHODS: This cross-sectional study utilizes a convenience sample obtained from the archives of an oral pathology laboratory from a higher education institution. Tissue sections from patients diagnosed with actinic cheilitis and carcinoma were immunohistochemically analyzed using monoclonal antibodies specific for smooth muscle alpha actin (SMA) and neuron-glial antigen 2 (NG2). Individual cells that stained positive for these proteins were counted in specific fields by means of histomorphometry. RESUlTS: Subsequent statistical analysis revealed a higher number of NG2-positive when compared with SMA-positive cells in both lesion types (p = 0.005) and these cells were located adjacent to blood vessels. The differences between normal oral mucosa, severe dysplasia, and carcinoma specimens were statistically significant (p = 0.009; p = 0.006). CONClUSION: These data strongly suggest that increased expression of NG2-and SMA-positive cells is associated with formation of blood capillaries, highlighting the importance of angiogenesis in tumor progression.Key words: Carcinoma; Pericytes; Myofibroblasts Expressão imuno-histoquímica de pericitos e miofibroblastos na matriz extracelular de queilite actínica oral e carcinoma de células escamosas: estudo comparativo REsUMO OBJETIVO: O objetivo do presente estudo foi realizar uma análise comparativa da queilite actínica e do carcinoma de células escamosas por meio de análise imuno-histoquímica. MÉTODOS: Este estudo transversal utilizou uma amostra de conveniência obtida dos arquivos de um laboratório de patologia oral de uma instituição de ensino superior. As secções de tecido de pacientes diagnosticados com queiliteactínica e carcinoma foram analisados pela técnica imuno-histoquímica usando anticorpos monoclonais específicos para alfa actina de músculo liso (SMA) e do antígeno neurônio/glial2 (ng2). As células com marcação positiva para estas proteínas foram contadas em campos específicos por meio de histomorfometria. RESUlTADOS: análise estatística subsequente revelou maior número de positivos para ng2 quando comparados com células SMA positivas em ambos os tipos de lesão (p = 0,005) seno que estas células foram localizadas adjacentes aos vasos sanguíneos. As diferenças entre mucosa oral normal, displasia grave e espécimes de carcinoma foram estatisticamente significativas (p = 0,009; p = 0,006). CONClUSÃO: Os dados sugerem, fortemente, que o aumento da expressão de células positivas para ng2 e SMA está associado à formação de capilares sanguíneos, destacando a importância da angiogênese na progressão tumoral.

Introduction: In recent years, cellular biostimulation induced by low-level laser therapy has been widely studied. Among some of the processes stimulated by low-level laser are cell cycle, phenotypic modulation as well as vascular changes, such as vasodilation and neoangiogenesis. The increased number of new blood vessels accelerates inflammation, and also increases wound healing. Neoangiogenesis is still an important process of tissue repair, since it always precedes collagen synthesis and matrix extracellular remodeling. Increasing scientific evidence has shown that photobiomodulation stimulates neoangiogenesis, fibroblast proliferation and collagen biosynthesis. Objective: Review the literature about the effects of low level laser therapy on neoangiogenesis and fibroplasia and describe how these processes occur in the tissue subjected to an injury. Methods and Matereials: The search tool used was the Medline / Pubmed and the following keywords were used: remodeling, wound healing, neoangiogenesis, fibroplasia, laser therapy, low-level laser. Manuscripts published from 1990 to 2017 were selected. Results: Increasing scientific evidence has shown that photobiomodulation stimulates neoangiogenesis, fibroblast proliferation and collagen biosynthesis. Conclusion: Neoangiogenesis always precedes collagen synthesis and matrix extracellular remodeling. However, little is known of the action of laser therapy in the late stages of tissue repair.