Mesenchymal stem cells transduced by stromal cell-derived factor-1α augment ischemic free flaps' survival.

Mesenchymal stem cells (MSCs) have the potential for differentiating into vascular endothelial cells. Stromal cell-derived factor-1α (SDF-1α) plays an important role in neovascularization of ischemic flaps. The authors evaluated the feasibility of applying MSCs transduced by SDF-1α gene to the treatment of early and partial ischemic free flaps survival. MSCs were isolated from Lewis rats and cultured in vitro. Recombinant adenovirus encoding SDF-1α gene (Ad-SDF-1α) was transduced into the MSCs. Lewis rats that underwent epigastric free flaps based on medial and lateral branches of superficial inferior epigastric vessels and femoral vessels were equally randomized into 4 groups, and injected with Ad-SDF-1α-transduced MSCs, MSCs, Ad-SDF-1α, and normal saline, respectively. Gene transduction, flaps survival, neovascularization, and expression level of SDF-1a protein were detected. The results showed that Ad-SDF-1α-transduced MSCs expressed higher SDF-1α both in vitro and in vivo, yielded more survival area, and resulted in higher neovascularization than any other groups. Interestingly, the necrotic sites of all free flaps were in the proximal end rather than in the distal end. In conclusion, Ad-SDF-1α-transduced MSCs can increase neovascularization of early and partial ischemic free flaps and augment the surviving areas.

Effect of piceatannol against malignant melanoma in vivo and in vitro.

OBJECTIVES: To study the antitumor effect of piceatannol (PIC) on malignant melanoma in vitro and in vivo. METHODS: B16F10 cells were cultured in vitro and treated with gradient concentrations of PIC. Cell viability was detected with methyl thiazolyl tetrazolium (MTT) assay; matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor (VEGF), spleen tyrosine kinase (Syk), and p-Syk were detected with Western blot; migration ability was detected with wound healing assay; invasion ability was detected with Transwell assay. Syk expression was suppressed through RNA interference for the detection of the possible mechanism of PIC in melanoma. An in vivo study was established by creating B16F10-bearing mice with intraperitoneal injection of PIC. RESULTS: The cell viability of B16F10 decreased with increasing PIC concentration. The results of the Transwell assay showed that invasion ability decreased with increasing PIC concentration, and healing time was prolonged at increased PIC concentration in the wound healing assay. Western blot results showed that PIC mainly inhibited the phosphorylation of Syk and inhibited the expression of MMP-2, MMP-9, and VEGF. RNA interference pointed out that blocking the expression of Syk can reveal the same inhibition effect on B16F10 cells as PIC. In vivo study revealed that different concentrations of PIC cangreatly inhibit melanoma progression. CONCLUSIONS: PIC might block the progression of malignant melanoma by inhibiting spleen tyrosine kinase.

Anterior skull base reconstruction with galeal-frontalis-pericranial flap based on temporalis myofascial flap.

Such a giant anterior skull base mucocele involving the orbito-ethmoido-maxillo-fronto sinuses is a rare case. This patient complained of a right orbital mass for 18 years, and he was recommended to our hospital for treatment. His history, physical examination, laboratory study results, diagnosis, and treatment are reported in detail. In conclusion, we show that modified transcranial pathway and ingenious assistant incision can get the utmost exposure and can obtain a satisfactory aesthetic result and that anterior skull base reconstruction with the galeal-frontalis-pericranial flap based on the temporalis myofascial flap for the first time can successfully prevent life-threatening complications from happening.

[Application of mixed reality in oromaxillofacial head and neck oncology surgery: a preliminary study].

Mixed reality (MR), characterized by the ability to integrate digital data into human real feeling, is a new technique in medical imaging and surgical navigation. MR has tremendous value in surgery, but its application in oromaxillofacial head and neck oncology surgery is not yet reported. This paper reports the application of MR in oromaxillofacial head and neck oncology surgery. The merits, demerits, and present research situations and prospects of MR are further discussed.

Metastatic tumors to the oral and maxillofacial region: a retrospective study of 19 cases in West China and review of the Chinese and English literature.

PURPOSE: The aim of this article was to obtain an overview of metastatic tumors to the oral and maxillofacial (OMF) region, especially the differences in the constituent ratios of primary cancers between the United States and China. PATIENTS AND METHODS: Clinical findings of 19 cases encountered in West China Hospital of Stomatology were summarized and the English and Chinese literature were reviewed and analyzed. The main clinical features of OMF metastases were summarized, with an emphasis on primary cancers' constituents. RESULTS: The lung, breast, kidney, liver, and prostate were the top 5 common primary sites of cancer. However, there was a significant difference in the primary cancers' constituents between United States and China (P < .001). The breast, kidney, prostate cancers, and melanoma of skin were more frequent primary cancers in United States than in China, whereas that of the lung, thyroid, liver, esophagus, and the stomach were more common in China than in United States. The proportions of the OMF metastatic lesions originating in the lung, kidney, liver, thyroid, and esophagus in all OMF metastatic tumors were higher than the corresponding primary cancers' prevalent proportions. CONCLUSIONS: The frequency of developing OMF metastasis is not always consistent with primary cancers' prevalence, which suggests that different cancers have different potentiality to develop OMF metastasis. Cancers of the kidney, liver, lung, thyroid, and esophagus were more likely to spread to the OMF region. In general screening of primary cancer, it would be helpful to take into account the metastatic potentiality of different cancers and primary cancers' prevalence in different countries in the case of occult primary.

Maxillofacial injuries caused by the 2008 Wenchuan earthquake in China.

PURPOSE: To describe the pattern of maxillofacial injuries sustained by survivors of the 2008 Wenchuan earthquake in the West China Hospital of Stomatology from May 12 to June 23, 2008. PATIENTS AND METHODS: Cross-sectional data were analyzed using hospital-based records of earthquake survivors admitted to the West China Hospital of Stomatology. A self-designed form to record information about variables such as the gender and age of the survivors and type of location of soft and hard tissue injuries was used. RESULTS: The age of earthquake survivors of maxillofacial injuries ranged from 4 to 84 years. Fractures and soft tissue injuries were the most common of all injuries in the maxillofacial region, constituting 40.7% and 38.9%, respectively. Thirteen patients (11.5%) had dental injuries and 9 (8.0%) also had other organ injuries. CONCLUSION: During the Wenchuan earthquake, the incidence of maxillofacial injuries in survivors was relatively low compared with injury in other organs. However, because most injuries were maxillofacial fractures and facial soft tissue damage, special attention was paid to maxillofacial injury when planning and providing emergency treatment. The effective management of earthquake injuries and those caused by other types of disaster requires a multidisciplinary approach, and maxillofacial surgeons should form an integral part of this multidisciplinary team.

Cutaneous metastasis from a parotid myoepithelial carcinoma: a case report and review of the literature.

Myoepithelial carcinoma of the parotid gland is a rare salivary gland tumour, and its distant cutaneous metastasis has not been reported to date. Here, we report a case of myoepithelial carcinoma of the left parotid gland, which had metastasised to the skin of the right thorax after parotidectomy and radiotherapy. Diagnosis of the primary and metastatic tumour was based on the clinical findings and was confirmed by immunohistochemistry. A literature review of the clinical features of the skin metastases of parotid malignancies and their related pathological mechanisms is included in this case study. It was noted that myoepithelial carcinoma of the parotid gland has the potential to develop distant skin metastasis, which may be indicative of widespread dissemination and poor prognosis. Attention should be paid to initial treatment of the primary tumour and to emerging cutaneous masses whose location is distant from the primary tumour during follow up.

Correlation between the expression of thrombospondin-1 and neovascularization in mucoepidermoid carcinoma.

BACKGROUND: Researchers have recently demonstrated that thrombospondin-1 (TSP-1) has an important function in regulating neovascularization. Whether it inhibits or accelerates neovascularization, however, is still controversial. We found few reports about the correlation between TSP-1 and vascularization in mucoepidermoid carcinoma. In this research, the distribution and expression of TSP-1 in mucoepidermoid carcinoma were investigated. We also analyzed (1) the correlation between the expression of TSP-1 and microvessel density (MVD), as an indicator of neovascularization activity, and (2) the effect of TSP-1 on neovascularization and tumor growth in the subcutaneous xenotransplanted model of mucoepidermoid carcinoma. METHOD: (1) The sites and intensity of expression of TSP-1 and the MVD were analyzed in 45 cases of mucoepidermoid carcinoma after surgery by the method of streptavidin-peroxidase (SP) immunohistochemistry; and (2) recombinant human thrombospondin-1 (rhTSP-1) was injected twice a week for five consecutive weeks around the tumor in the subcutaneous xenotransplanted tumor model of mucoepidermoid carcinoma in nude mice. Each week, the tumor size was measured, in order to draw the growth curve of the xenotransplanted tumor model of mucoepidermoid carcinoma, and MVD was measured. RESULTS: (1) The positive expression of TSP-1 protein was 57.78% (26/45). Most positive staining for TSP-1 was found in the cytoplasm of the cancer cells, while some staining occurred in the extracellular matrix. The mean MVD in 45 cases of mucoepidermoid carcinoma was 58.17 +/- 19.77 per 100 visual fields. Tumors with a high expression of TSP-1 showed a low MVD value, and the TSP-1 immunocompetence and microvessel density showed a significant negative correlation (r(s) = -0.947, P < 0.001). (2) The xenotransplanted tumors with the injection doses of 1.25, 0.75 and 0.25 microg/ml respectively were 36.97%, 53.36% and 73.61% of the size of the control group ((451 +/- 92), (651 +/- 113), (898 +/- 86) and (1220 +/- 157) mm(3) respectively, F = 53.167, P < 0.001), and their weights were respectively 35.14%, 51.35% and 70.27% of the control group ((1.3 +/- 0.5), (1.9 +/- 0.5), (2.6 +/- 0.3), and (3.7 +/- 0.7) g respectively, F = 62.669, P < 0.001). Their MVDs were 25.00%, 45.93%, and 72.20% respectively of the control group and concentration dependent (15.43 +/- 3.45, 28.35 +/- 4.24, 44.57 +/- 3.35 and 61.73 +/- 5.43 per 100 visual fields respectively, F = 54.582, P < 0.001). CONCLUSIONS: The TSP-1 has a higher expression in mucoepidermoid carcinoma and the expression has a significant negative correlation with neovascularization. The TSP-1 inhibits neovascularization and tumor growth, and it might be a new biological therapy for treatment of patients with mucoepidermoid carcinoma.

[Correlation between the expression of thrombospondin-1 and the angiogenesis in mucoepidermoid carcinoma].

OBJECTIVE: To study the relationship between the expression of thrombospondin-1 (TSP-1) and the angiogenesis in mucoepidermoid carcinoma. METHODS: Immunohistochemistry were applied to detect the expression of TSP-1 and the value of microvessel density (MVD) in 45 mucoepidermoid carcinoma patients. RESULTS: Positive expressions of TSP-1 protein were detected in 26 of the 45 (57. 78%) cases. Most positive staining for TSP-1 was observed in the cytoplasm of the cancer cells, some of those were in the extracellular matrix. The mean MVD in 45 cases with mucoepidermoid carcinoma was 60. 68 +/- 19.84 vessels per 100 field of vision. Tumors with a high expression of TSP-1 showed a low value of MVD and the correlation between TSP-1 immunocompetence and microvessel density was highly significant (r(s) = -0.942, P < 0.001). CONCLUSION: The TSP-1 is expressed in most mucoepidermoid carcinoma and were associated with neovascularization. TSP-1 is likely to inhibit the extensive neovascularization and increased TSP-1 expression might inhibit angiogenic phenotype in mucoepidermoid carcinoma.

Effects of lentivirus-mediated shRNA targeting integrin-linked kinase on oral squamous cell carcinoma in vitro and in vivo.

Integrin-linked kinase (ILK), a highly conserved intracellular protein of serine/threonine protein kinase activities, which is associated with the integrin and growth factor receptor signaling pathway, is involved in the regulation of cell proliferation, apoptosis, differentiation, migration and epithelial-mesenchymal transition (EMT). Findings of a previous study showed that ILK overexpression was strongly correlated with a more aggressive tumor phenotype, recurrence and poor survival for oral squamous cell carcinoma (OSCC) patients, as well as some EMT markers. In order to investigate the underlying mechanisms involved, a lentivirus-mediated short hairpin RNA (shRNA) was employed to downregulate ILK. The results showed that the knockdown of ILK inhibited cell growth, adhesion and invasion ability in vitro, and OSCC cells deficient of ILK were blocked in the S phase and underwent apoptosis. Additionally, ILK shRNA inhibited EMT by impairing the expression of Snail, Slug and Twist2 and enhacning E-cadherin expression. ILK shRNA suppressed the phosphorylation of downstream signaling targets Akt and GSk-3ß. In addition, the knockdown of ILK inhibited tumor growth, invasion and metastasis of xenograft tumors in vivo. These results suggested that ILK is a promising therapeutic target for the treatment of OSCC.

Angiogenic gene-modified myoblasts promote vascularization during repair of skeletal muscle defects.

Vascularization is thought to be a principle obstacle in the reconstruction of skeletal muscle defects. Long-term survival of reconstructed skeletal muscle is dependent on good vascularization. In this study, we upregulated angiogenic gene expression in myoblasts in an attempt to promote vascularization during repair of skeletal muscle defects. Skeletal myoblasts were isolated and expanded from newborn male Sprague-Dawley (SD) rats. The cells were transfected with human vascular endothelial growth factor 165 (VEGF-165) or human stromal cell-derived factor 1 (SDF-1), using Lipofectamine™ 2000 transfection reagent, prior to seeding onto calf collagen scaffolds. Gene and protein overexpression was verified by ELISA, RT-PCR and western blot analysis. Cell-seeded scaffolds were transplanted into back muscle defects in female SD rats. At weeks 2, 4 and 8 after transplantation, Y chromosome detection was used to observe the survival of growth factor-producing cells within the scaffolds in vivo. Capillary density was investigated using microvessel density detection, haematoxylin and eosin (H&E) staining and immunohistochemical staining. We found that vascularization was enhanced by transfected myoblasts compared with non-transfected myoblasts. In addition, VEGF-165 and SDF-1 had a synergistic effect on vascularization during repair of skeletal muscle defects in vivo. In conclusion, we have combined myoblast-seeded collagen sponge with gene therapy, resulting in a promising approach for the construction of well-vascularized skeletal muscle.

New advances in the mesenchymal stem cells therapy against skin flaps necrosis.

Mesenchymal stem cells (MSCs), multipotential cells that reside within the bone marrow, can be induced to differentiate into various cells, such as osteoblasts, adipocytes, chondrocytes, vascular endothelial progenitor cells, and other cell types. MSCs are being widely studied as potential cell therapy agents due to their angiogenic properties, which have been well established by in vitro and in vivo researches. Within this context, MSCs therapy appears to hold substantial promise, particularly in the treatment of conditions involving skin grafts, pedicle flaps, as well as free flaps described in literatures. The purpose of this review is to report the new advances and mechanisms underlying MSCs therapy against skin flaps necrosis.

Case report: postradiation chondrosarcoma with a short latency period of 6 months.

We describe a case of postradiation chondrosarcoma after basal cell carcinoma treatment. At the time he presented, the patient was a 35-year-old man who had received radiotherapy at a dose of 70 Gy for 8 weeks. Six months after radiation treatment, a rapidly growing mass at the upper right alveolar ridge of the gums, where radiation had been given, was diagnosed as chondrosarcoma. Generally, chondrosarcoma occurs after a latency period of several years following radiation. However, there are a few relevant reports indicating that maxillofacial chondrosarcoma can develop after radiotherapy for basal cell carcinoma, with a short latency of 6 months. We hypothesize that the dosage and treatment time of radiation may have played a role in the opening/closing of the Hh-signaling pathway in the case of this patient.

Expression of integrin-linked kinase in adenoid cystic carcinoma of salivary glands correlates with epithelial-mesenchymal transition markers and tumor progression.

Integrin-linked kinase (ILK) plays a key role in cell-excellular matrix interactions mediated by integrins and several growth factors, regulating cell proliferation, apoptosis, differentiation, and migration. It has also been implicated in the development and progression in several malignancies involving epithelial to mesenchymal transition (EMT). However, the correlations between ILK and EMT markers and the progression of salivary adenoid cystic carcinoma (SACC) have not been well elucidated. Here, by immunohistochemistry, we studied the expression of ILK, Snail, E-cadherin, and N-cadherin in 94 SACC specimens and analyzed their correlations with clinicopathologic characteristics. Positive expression of ILK protein was detected in 76.6 % of the tumors. Increased expression of ILK and Snail and decreased E-cadherin expression correlated strongly with tumor solid type (P = 0.017, P = 0.008, and P = 0.038, respectively), advanced TNM stage (P = 0.021, P = 0.034, and P = 0.009, respectively), and increased risk of recurrence (P = 0.023, P = 0.011, and P = 0.039, respectively) and distant metastasis (P < 0.001, P < 0.001, and P = 0.001, respectively). Moreover, up-regulation of Snail and N-cadherin and down-regulation of E-cadherin correlated significantly with ILK over-expression (P < 0.001, P = 0.001, and P < 0.001, respectively) and a neural-invasive phenotype (P = 0.017, P = 0.002, and P < 0.001, respectively). Taken together, our results suggest that ILK may have an important role in progression and metastasis of SACC, possibly through EMT involving up-regulation of Snail and consequent aberrant expression of E-cadherin and N-cadherin. ILK should be considered as a potential therapeutic molecular target for patients with SACC.

Over-expression of integrin-linked kinase correlates with aberrant expression of Snail, E-cadherin and N-cadherin in oral squamous cell carcinoma: implications in tumor progression and metastasis.

Integrin-linked kinase (ILK), an intracellular protein with serine/threonine protein kinase activities, plays a key role in integrin mediated cell-excellular matrix interactions, regulating cell proliferation, apoptosis, differentiation, and migration. ILK has been implicated in the development and progression in several malignancies. However, the role of ILK and ILK-mediated epithelial-mensenchymal transition (EMT) in the progression of oral squamous cell carcinoma (OSCC) has not been well understood. Here, by immunohistochemistry, we studied the expression of ILK, Snail, E-cadherin and N-cadherin in 98 primary OSCC specimens and analyzed their correlations with clinicopathologic profiles and clinical outcome. We also investigated the expression of ILK in 42 corresponding lymph node metastases. Positive expression of ILK protein was detected in 87.8 % of the primary tumors and 100 % of metastatic lesions. Increased ILK expression was correlated strongly with enhanced tumor invasion, higher tumor grade, advanced clinical stage, positive lymph node status and increased risk of recurrence. Higher ILK expression was also observed in lymph node metastases in comparison with the corresponding primary tumor. Moreover, up-regulation of Snail and N-cadherin and down-regulation of E-cadherin correlated significantly with both ILK over-expression and tumor invasion. Patients with higher ILK expression exhibited shorter disease-free survival while those with absent E-cadherin expression exhibited shorter overall and disease-free survival. Taken together, our results suggest that ILK may have an important role in progression and metastasis of OSCC, possibly through EMT involving up-regulation of Snail and consequent aberrant expression of E-cadherin and N-cadherin. ILK should be considered as a critical prognostic indicator for patients with OSCC.

Primary tumor prevalence has an impact on the constituent ratio of metastases to the jaw but not on metastatic sites.

This article provides an overview of metastases to jaws (MJ), mainly concerning the differences between American and Chinese patients, and exploring the relationship between the primary tumors' prevalence (PTP) and constituent ratio of MJ. Information concerning of 399 MJ cases in 215 papers, including one new case in our hospital, was subjected to statistic analysis. The main clinical features of MJ, such as constituent ratio of PTP and that of MJ, metastatic sites, treatments, and prognosis were summarized. Breast, lung, kidney, prostate and thyroid (in descending order) were the leading primary sites of MJ. Furthermore, the constituent ratio of MJ was found to be correlated with that of PTP in all subjects including American and Chinese subjects in our study. As to metastatic sites in the mandible, a specific "M" shaped pattern appeared regardless of the tumor type or constituent ratios of MJ were in all subjects. Almost all subjects received traditionally palliative treatments, and the prognosis was quite poor. The PTP had a significant impact on the constituent ratio of MJ. However, it was the properties of the microenvironment rather than characteristics or constituent ratios of tumor cells, that decided the metastatic sites in various tumor subjects.

Intratumoral c-Met expression is associated with vascular endothelial growth factor C expression, lymphangiogenesis, and lymph node metastasis in oral squamous cell carcinoma: implications for use as a prognostic marker.

Hepatocyte growth factor has been identified as a lymphangiogenic factor in experimental animal models. However, the correlation between hepatocyte growth factor or c-Met expression and lymphangiogenesis in human spontaneous tumors has been rarely reported, and the distribution pattern of c-Met on tumor-related lymphatic vessels remains to be further investigated. Lymphatic vessel density, lymphatic invasion, the expression of hepatocyte growth factor, c-Met, and vascular endothelial growth factor C proteins were evaluated by immunohistochemistry in 76 cases of oral squamous cell carcinoma. The distribution of c-Met on lymphatic endothelium was examined. High expression of c-Met in tumor cells was significantly associated with advanced clinical stage (P = .045), high expression of vascular endothelial growth factor-C (P < .001), higher peritumoral lymphatic vessel density (P = .003), higher incidence of peritumoral lymphatic invasion (P = .032), and positive lymph node status (P = .005), in spite of its negative expression on most lymphatic vessels. Patients with high-c-Met expression tumors exhibited shorter overall survival and disease-free survival (P < .001 and P = .010, respectively). Taken together, our results provide indirect evidence for an association and possible regulatory link of c-Met with the lymphangiogenic factor, vascular endothelial growth factor C, and, by extension, with lymphangiogenesis and lymph node metastasis, suggesting important prognostic significance of c-Met for patients with oral squamous cell carcinoma.

Derived vascular endothelial cells induced by mucoepidermoid carcinoma cells: 3-dimensional collagen matrix model.

Mucoepidermoid carcinoma undergoes uniquely vigorous angiogenic and neovascularization processes, possibly due to proliferation of vascular endothelial cells (ECs) induced by mucoepidermoid carcinoma cells (MCCs) in their three-dimensional (3D) microenvironment. To date, no studies have dealt with tumor cells and vascular ECs from the same origin of mucoepidermoid carcinoma using the in vitro 3D microenvironment model. In this context, the current research aims to observe neovascularization with mucoepidermoid carcinoma microvascular ECs (MCMECs) conditioned by the microenvironment in the 3D collagen matrix model. We observed the growth of MCMECs purified by immunomagnetic beads and induced by MCCs, and characteristics of tubule-like structures (TLSs) formed by induced MCMECs or non-induced MCMECs. The assessment parameters involved the growth curve, the length, the outer and inner diameters, and the wall thickness of the TLSs, and the cell cycle. Results showed that MCCs induced formation of the TLSs in the 3D collagen matrix model. A statistically significant difference was noted regarding the count of TLSs between the control group and the induction group on the 4th day of culture (t=5.00, P=0.001). The outer and inner diameters (t(1)=5.549, P(1)=0.000; t(2)=10.663, P(2)=0.000) and lengths (t=18.035, P=0.000) of the TLSs in the induction group were statistically significant larger than those in the control group. The TLSs were formed at the earlier time in the induction group compared with the control group. It is concluded that MCCs promote growth and migration of MCMECs, and formation of the TLSs. The 3D collagen matrix model with MCMECs induced by MCCs in the current research may be a favorable choice for research on pro-angiogenic factors in progression of mucoepidermoid carcinoma.

Expression of CD44V6 in parotid pleomorphic adenoma and carcinoma ex pleomorphic adenoma.

BACKGROUND: Change in expression of CD44 variant (CD44v) has been observed in several types of aggressive carcinomas. This pattern of expression might be associated with carcinogenesis of parotid pleomorphic adenoma (PPA) which is not widely studied. In this study, we aimed to investigate the expression of CD44v6 in the PPA before and after recurrence, between non-recurrent PPA, recurrent PPA, and PPA with carcinogenesis so as to identify whether the expression differences have existed before the recurrence and its significance for predicting the recurrence. METHODS: Expression differences of CD44v6 were detected by immunohistochemistry in samples of non-recurrent PPA, PPA before and after the recurrence, carcinoma in pleomorphic adenoma (CPA) and normal parotid. RESULTS: The expression of CD44v6 was significantly higher in the group before the recurrence than that after the recurrence (p < 0.05). The expression of CD44v6 after recurrence was significantly lower than that in the non-recurrent group (p < 0.05) while the high level of CD44v6 expression in the non-recurrent group, was significantly lower than in the group with CPA (p < 0.05). However, no significant difference was observed between the group after recurrence and CPA. CONCLUSION: The decrease of CD44v6 expression promoted the recurrence and carcinogenesis of PPA, and the expression was decreased further in the process. The expression differences of CD44v6 had appeared before the recurrence.

Expression of Twist in different subtype of ameloblastomas.

OBJECTIVE: The objective of this study was to investigate the pattern of Twist expression in a series of ameloblastomas, and to study the possible role of Twist in the bone destruction and local invasiveness of ameloblastoma variants. STUDY DESIGN: Immunohistochemical study was performed for Twist protein in 53 ameloblastomas (32 solid/multicystic [SA] and 21 unicystic [UA]). RESULTS: The salient finding was that expression of Twist was related to the histological subtype of tumors, as there was a higher expression in SA (14/32, 43.75%) as compared to UA (4/21, 19.05%) (P < .05). Both nuclei and cytoplasm positivities were detected in positive cases, whereas cytoplasmic staining was diffused and predominant. Cases rich in stromal cells showed a higher percentage of positive cells than those with less stroma. CONCLUSIONS: Our results suggest that Twist expression might be associated with invasion in ameloblastoma variants, and stromal cells might play a regulatory role during tumor development.