Review: Benign Fibro-osseous lesions is a generic term that includes a group of diseases affecting jaw and facial bones. Myofibroblasts (MFs) are cells that share properties of fibroblasts and smooth muscle cells. They have a main role in tissue growth, development and healing, and during organ fibrosis and cancers. Alpha smooth muscle actin (α-SMA) is recognized to be present in smooth muscle cells, myoepithelial cells and pericytes. So it used to identify soft tissue neoplasms of smooth muscle, myoepithelial and myofibroblastic origin. Ki67 is one of the markers which is used to detect cellular proliferation in growing cells. Aim of study:The present study aimed to examine the immunohistochemical labeling of α-SMA in juvenile ossifying fibromas (JOFs), central ossifying fibromas (COFs) and peripheral ossifying fibromas (POFs) and to correlate its expression with their proliferative ability through Ki67 expression.Material and Methods: Immunohistochemical expression of α-SMA and Ki67 was evaluated in 10 samples of each of JOF, COF, and POF.Results: JOFs showed the highest mean value of α-SMA and Ki67 expression (16.69±5.25) (17.04±2.75) followed by COFs group (5.93±1.94) (8.33±1.23) while POFs showed the lowest mean value (1.54±0.64) (3.14±0.95), respectively, with a statistically significant positive correlation between α-SMA and Ki67 in all groups together (P-value ≤0.05). Conclusion:Overexpression and significant positive correlation between α-SMA and Ki67 expression in JOFs, COFs, and POFs indicate the important role of MFs in the aggressive behavior of JOFs when compared with COFs and POFs through enhancing cellular proliferation, cellular migration, angiogenesis, and extracellular proteolytic activity and influencing matrix formation.

Review: Odontogenic cysts represent 7 to 15% of all maxillofacial lesions. TWIST proteins have essential physiological roles during morphogenesis, tissue healing and fibrosis. TWIST protein attaches to E-box DNA response members to suppress or induce transcription. Also, TWIST expression can stimulate the epithelial-mesenchymal transition (EMT) process and is associated with bad prognosis. Vascular Endothelial Growth Factor (VEGF) is a multifunctional cytokine that has a role in increasing the vascular permeability and angiogenesis which is reported in various lesions. Aim of study:The present study aimed to examine the immunohistochemical labeling of Twist in dentigerous cysts (DCs), odontogenic keratocysts (OKCs) and calcifying odontogenic cysts (COCs) and correlate its expression with their angiogenic ability through VEGF expression.Material and Methods: Immunohistochemical localization of Twist and VEGF was evaluated in 10 samples of each DC, OKC, and COC. Results:OKCs showed the highest mean value of TWIST and VEGF expression (13.53±5.52) (14.49±5.14) followed by COCs group (6.01±1.77) (7.51±1.66) while DCs showed the lowest mean value (2.77±.68)(4.35±.68), respectively, with a statistically significant positive correlation between TWIST and VEGF in all cyst groups together and also was observed in each group separately (P-value ≤0.05). Conclusion:Overexpression and significant positive correlation between TWIST and VEGF expression in DCs, OKCs and COCs indicates their important role in pathogenesis of these cysts. Also, indicates their potential link with aggressiveness and invasive growth behavior observed in OKCs. In addition, proper targeting of the EMT process may improve treatment of OKCs. Twist may be also a novel therapeutic target for angiogenesis