Ameloblastic carcinoma (AC) is a rare malignant odontogenic neoplasm that tends to occur in the mandible rather than in the maxilla. This malignancy is classified as a tumor that combines the morphological features of ameloblastoma and carcinoma, regardless of the presence or absence of metastasis. In addition, AC has been classified into two types, primary and secondary. The former develops de novo and the latter develops by malignant transformation of a pre-existing benign ameloblastoma. The present study describes the case of a 22-year-old patient with primary AC of the maxilla. A review of the literature focusing on the clinical details, treatment results and histopathological and phenotypic information available for ameloblastic carcinoma of the maxilla from a 60-year period was also performed. As a result, it was found that primary AC is dominant in the maxilla and does not exhibit an aggressive phenotype compared with secondary AC. In addition, the presence of recurrence was found to correlate with mortality, indicating that early, aggressive and complete removal of the tumor is the best treatment for survival.

BackgroundMaxillary gingival squamous cell carcinoma (MGSCC) occurs rather infrequently, compared to tongue and mandibular gingival carcinomas, among the cancers of the oral cavity. Therefore, significant numbers of MGSCC cases have not been statistically analysed. The aim of this study is to clarify the prognostic factors for MGSCC. MethodsWe performed the statistical analysis of 90 MGSCC cases primarily treated in our department from 1999 to 2014. ConclusionsThe patients (male: 36, female: 54) were aged between 38 and 93 years, and the mean age was 68.7 years. The number of patients in each tumour stage according to the TNM classification was as follows: T1: 15 cases, T2: 32 cases, T3: 13 cases, and T4: 30 cases. Forty-two patients were treated only by surgery, 5 only by radiotherapy, 3 by preoperative radiotherapy and surgery, and 40 patients were treated by combination therapy with preoperative chemoradiotherapy and surgery. Neck dissections were performed in 40 cases including 29 cases (11 primary and 18 secondary cases) of histopathologically diagnosed lymph node metastases. Extranodal extension was found in 74.3% cases with metastatic lymph nodes. The 5-year overall survival rate was 81.9%. In univariate analysis, the site of occurrence, stage of tumour, lymph node metastasis, and treatment contributed to the 5-year survival rate. Multivariate analysis demonstrated that the site of occurrence (posterior region) was an independent prognostic factor. Seventeen deaths occurred due to the primary disease, while three deaths were caused by other diseases. ConclusionThe posterior region cancers, according to the classification based on site of occurrence, were independent predictors of poor 5-year overall survival rate.

Introduction Keratinocytes derived from pluripotent stem cells have a short proliferative lifespan under conventional culture conditions that are optimized for keratinocytes. Recently, a Rho kinase inhibitor, Y-27632, had been used as a standard supplement for culture medium in which the proliferative lifespan of postnatal keratinocytes was markedly expanded. In addition, recombinant human laminin-511 was demonstrated to be an adhesive ligand for promoting proliferation of cultured epidermal keratinocytes. Based on this knowledge, efficacies of Y-27632 and a laminin511-derived recombinant fragment, known as laminin-511 E8 fragment (LN-511-E8), were evaluated for establishing cultivation methods of keratinocyte differentiated from human embryonic stem cells (hESC). Methods Differentiated cells from hESCs, which were established with clinical grade in previous study, were seeded onto culture dishes coated with LN-511-E8 and co-cultured with a mouse feeder layer in serum-free medium supplemented with Y-27632. Before serial cultivation, hESC-derived keratinocytes were separated from other differentiated cells by trypsinization. The isolated hESC-derived keratinocytes were used for evaluating clonogenicity, gene expression analysis for keratinocyte markers, potency of terminal differentiation by air-lifting culture, and long-term proliferation activity by serial cultivation. Moreover, efficacies of Y-27632, LN-511-E8, and mouse feeder layer were evaluated on proliferation of hESC-derived keratinocytes. Results hESC-derived keratinocytes with activity of clonal growth were successfully isolated by trypsinization and exhibited potency of differentiation to form stratified epidermal equivalents with expressions of progenitor and differentiation markers of epidermal keratinocyte. Y-27632 and LN-511-E8 were required for maintaining the proliferative activity of the hESC-derived keratinocytes in serially cultivation using mouse feeder layer with stable doubling time during logarithmic growth phase. Conclusions These results indicate the utility of Y-27632 and LN-511-E8 for serial cultivation of hESC-derived keratinocytes, which have a potential for fabricating allogeneic cellular products in clinical situations for regeneration of stratified epithelial tissues.

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