Epidemiology, etiopathogenesis, and management of MRONJ: A European multicenter study.

INTRODUCTION: The purpose of this European multicenter study was to describe the general characteristics and risk factors of MRONJ lesions as well as their clinical diagnosis and management at different European Oral and Maxillofacial Surgery centers, in order to minimize selections biases and provide information about the epidemiology, etiopathogenesis, and the current trends in the treatment of MRONJ across Europe. MATERIALS AND METHODS: The following data were registered for each patient: gender; age at MRONJ diagnosis; past medical history; indication for antiresorptive or antiangiogenic therapy; type of antiresorptive medication; local risk factor for MRONJ; MRONJ Stage; anatomic location and symptoms; treatment; surgical complications; recurrence. RESULTS: A total of 537 patients (375 females, 162 males) with MRONJ were included. Statistically significant associations were found between patients with metastatic bone disease and recurrences (P < 0.0005) and between advanced MRONJ stages (stages 2 and 3) and recurrences (P < 0.005). Statistically significant associations were also found between male gender and recurrences (P < 0.05), and between MRONJ maxillary sites and recurrences (P < 0.0000005). CONCLUSIONS: A longer mean duration of antiresorptive medications before MRONJ onset was observed in patients affected by osteoporosis, whereas a shorter mean duration was observed in all metastatic bone cancer patients, and in particular in those affected by prostate cancer with bone metastases or multiple myeloma. Surgery plays an important role for the management of MRONJ lesions.

The prognostic role of claudins -1 and -4 in oral squamous cell carcinoma.

Claudin dysregulation has been described in various tumor types; however, its clinical relevance is poorly understood. We present a study in which we assessed the expression of claudin 1 (CLDN1) and CLDN4 in oral squamous cell carcinoma (OSCC), as well as their prognostic relevance. Immunohistochemical analysis of CLDN1 and CLDN4 expression was carried out on tissue sections from 65 OSCCs. The presence of CLDN1 in the invasive front of tumor islands was associated with neck node metastasis, and the expression of CLDN4 was associated with higher histological grade, and tumor recurrence. Membranous staining for CLDN4 in tumor cells, and weak intensity of CLDN4 immunoexpression were predictive for poorer survival. In a multivariate analysis for disease recurrence, CLDN1 immunostaining was statistically significant. Specifically, CDLN1 expression in the tumor invasive front was associated with tumor recurrence. Our results indicate that CLDN4 expression is correlated with poor prognosis, and CLDN1 expression may be an indicator of recurrence of OSCC.

Expression of podoplanin in the invasion front of oral squamous cell carcinoma is not prognostic for survival.

Podoplanin is involved in actin remodeling of the cytoskeleton of tumor cells and may promote tumor cell invasion by increasing cell motility and formation of filopodia-like membrane protrusions. Podoplanin is expressed in a variety of tumors, but its role in head and neck cancer, particularly in oral squamous cell carcinoma, remains unclear. We studied podoplanin expression by immunohistochemistry in 92 oral squamous cell carcinomas (OSCC) using a monoclonal antibody against an epitope of podoplanin (D2-40). In terms of the number of stained cells, 34 OSCC (38 %) had low podoplanin expression (less than 33 % of cells), 33 (36 %) showed moderate expression (between 34 and 66 % of cells), and 21 (22 %) showed high expression. The intensity of immunostaining was strong in 26 (28 %) cases, moderate in 36 (40 %), and weak or negative in the remaining 30 tumors (32 %). Immunohistochemical expression of podoplanin was associated with a tumor histological grade. A diffuse pattern of podoplanin expression significantly decreased in moderately differentiated (37 %) and poorly differentiated (20 %) carcinomas compared to well-differentiated (43 %) carcinomas. In addition, the focal expression of podoplanin in the invasion front of the tumor, without expression in the tumor center, was observed in 72 % of well-differentiated tumors, 27 % of moderate tumors, and 0 % of poorly differentiated tumors. Moreover, a trend was found toward an association of diffuse podoplanin staining with the development of second primary carcinomas (13 %), in contrast to its expression in the invasion front (3 %). No association was observed between podoplanin expression and nodal metastasis.