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Objective: Adenoid cystic carcinoma (AdCC) is a rare, indolent salivary gland tumor that is reported to be driven by fusion genes. However, MYB/MYBL1-NFIB fusions have been detected in <60% of all AdCC cases and the oncogenic driver mutations in approximately 40% of AdCC remain unknown. Our aim was to identify novel gene fusions in AdCC.Study Design: We investigated 20 AdCC cases using a targeted RNA sequencing panel to identify gene fusions and performed quantitative real-time reverse transcription polymerase chain reaction to assess MYB, MYBL1, and NFIB expression levels.Results: A total of 36 fusion transcripts in 15 cases were detected and validated by Sanger sequencing. The MYB-NFIB and MYBL1-NFIB fusion genes were detected in 9 and 3 cases, respectively, in a mutually exclusive manner. Furthermore, novel gene fusions, namely, NFIB-EPB41L2, MAP7-NFIB, NFIB-MCMDC2, MYBL1-C8orf34, C8orf34-NFIB, and NFIB-CASC20, were identified. Among them, NFIB-EPB41L2 and NFIB-MCMDC2 are thought to activate MYB and MYBL1 expression, respectively, through the insertion of a genomic segment in proximity to MYB and MYBL1 genes, respectively.Conclusion: Six novel gene fusions other than MYB/MYBL1-NFIB were identified. The detection of novel fusion genes and investigation of the molecular mechanism will contribute to the development of novel molecular targeted therapies for this disease. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to investigate the prognostic effects of clinical and histologic findings in patients with mucoepidermoid carcinoma (MEC) of minor salivary glands.Study Design: This retrospective clinical review included 63 patients (30 males, mean age 52.8 years) with minor salivary gland MEC treated at our hospital from 1994 to 2019. Overall survival (OS) or disease-free survival was determined using the Kaplan-Meier limit method. Correlations between different factors and survival rates were assessed using chi-square tests.Results: The 10-year OS rate was 91.2%. Low- or intermediate-grade MEC had a good prognosis regardless of the surgical margin, whereas high-grade MEC had a poor 10-year OS rate (64.2%). Ten patients developed recurrence or metastasis after primary surgical resection, of whom 6 were diagnosed with a high-grade tumor. The most frequently affected site was the palate, whereas the mandibular gingiva was the most commonly affected site during recurrence. Of 4 patients who received chemotherapy and/or radiotherapy postsurgery, 2 had local recurrence and/or neck lymph node metastasis and 1 died from MEC.Conclusion: Patients with low- or intermediate-grade MEC exhibited satisfactory survival after surgery. In patients with high-grade tumors, it has been suggested that survival rates are poor and do not improve following adjuvant therapy. [ABSTRACT FROM AUTHOR]

Objectives: Postoperative mandibular fracture (PMF) after marginal resection (MR) of the mandible remains an unresolved issue, and it has been reported that at least 10 mm of postoperative mandibular body height (PMBH) is required to prevent PMF. This study evaluated the clinical, physical, and structural risk factors for PMF in MR patients and determined appropriate preventive measures for PMF. Study Design: This retrospective study included 44 patients with lower gingival carcinoma who underwent MR. PMF occurred in four of these patients. Thirteen associated factors identified from medical records and radiographs were statistically analyzed. Results: Mandibular body height (MBH) preservation ratio originally evaluated as less than 0.3, more than 20 remaining teeth after surgery, and inferior alveolar canal (IAC) exposure were significant risk factors for PMF. Prostheses and number of remaining teeth were also correlated with PMF. Conclusions: The preserved mandibular bone should be reinforced in patients with an MBH preservation ratio of less than 0.3, more than 20 remaining teeth after surgery, and intraoperative IAC exposure. Patients with prostheses are at an increased risk of PMF compared with those without because of stable occlusion and a strong occlusal force. Our novel findings provide useful reference standards for PMF prevention in MR patients. [ABSTRACT FROM AUTHOR]

Summary: Keratocystic odontogenic tumor is a cystic lesion that behaves more aggressively than other jaw cysts. One of its characteristic histologic features is a parakeratinized uniform layer of lining epithelium. A jaw cyst lined with orthokeratinized epithelium is called an orthokeratinized odontogenic cyst. These keratinized jaw cysts are thought to be separate entities, although their histopathogenesis has not been fully assessed. To better understand these lesions, we performed comprehensive immunohistochemical profiling of the keratin expression of each. Orthokeratinized odontogenic cysts expressed keratin 1, keratin 2, keratin 10, and loricrin, suggesting differentiation toward normal epidermis. Keratocystic odontogenic tumors expressed keratin 4, keratin 13, keratin 17, and keratin 19, which is a unique expression pattern reminiscent of a mucosal squamous epithelium and an epithelial appendage. In neonatal rat tooth germ, cells strongly positive for keratin 17 and keratin 19 were observed, specifically in the dental lamina, implying the origin of keratocystic odontogenic tumor. GLI2, a downstream effector of hedgehog signaling, was significantly expressed in keratocystic odontogenic tumor and basal cell carcinoma, accompanied with robust expression of keratin 17, mammalian target of rapamycin, and BCL2. The expression of these GLI2- or keratin 17-related factors was not significantly observed in orthokeratinized odontogenic cysts. These findings provide evidence to support the viewpoint that keratocystic odontogenic tumor and orthokeratinized odontogenic cyst are separate entities, and furthermore suggest their characteristic histology, pathogenesis, and biological behaviors. [Copyright &y& Elsevier]

Objectives: Retropharyngeal lymph node (RPLN) metastasis is extremely rare, and prognosis is significantly poor in oral cancer. We retrospectively examined the management of RPLN metastases in oral cancer.Materials and Methods: A total of 1247 patients with oral cancer were treated at our department from January 2002 and December 2016. Among these patients, 374 (30%) had histologically positive lymph node metastases. Of these, 15 patients (1.2%) were diagnosed with RPLN metastases. We evaluated the diagnostic period, size, recurrence pattern, laterality, treatment, and therapeutic outcomes. The Kaplan-Meier method was used to determine overall survival (OS) among the RPLN metastasis group, cervical lymph node (CLN) metastases group, and treatment methods group for RPLN metastases.Results: One patient had RPLN involvement at the initial treatment, and RPLN involvement in other patients was found subsequently. The mean duration in confirming RPLN metastases was 228 days (range, 50-867 days). Surgical therapy was performed in 5 patients, chemoradiotherapy in 7 patients, and best supported care (BSC) in 3 patients. The cumulative 5-year OS rate for the RPLN metastasis group (n = 15) was 38.1%, compared with the rate of 71.3% for the CLN group (n = 359). Regarding the therapeutic approach for RPLN metastases, OS rates were 80.0% (n = 5) in the surgical therapy group, 28.6% (n = 7) in the chemoradiotherapy group, and 0% (n = 3) in the BSC group.Conclusion: Early detection and surgical treatment of RPLN metastases are associated with increased survival rate in oral cancer. [ABSTRACT FROM AUTHOR]

A 60-year-old woman presented to our department with severe tongue pain. On initial examination, the mucosal surface of the tongue was intact but a hard submucosal mass on the dorsum of the tongue was detected on palpation. Magnetic resonance imaging demonstrated an ill-defined tumor in the intrinsic tongue muscles. Sequential whole-body positron emission tomography/computed tomography revealed a tumor of the pancreas apart from the tongue lesion, and upper gastrointestinal endoscopy revealed gastric mucosa ulceration. On biopsy, the tongue lesion was confirmed to be metastatic gastric adenocarcinoma, and the gastric ulcer was simultaneously diagnosed as poorly differentiated gastric adenocarcinoma. The definitive diagnosis was thus gastric adenocarcinoma and synchronous pancreatic cancer, with gastric carcinoma metastases to the tongue. We administered FOLFIRINOX treatment for pancreatic cancer and FLTAX treatment for gastric cancer. Because of difficulty with oral intake due to the growth of the tongue lesion, we administered palliative radiation therapy at a dose of 30 Gy in 10 fractions following which the patient was able to resume oral intake and was satisfied with this outcome. She died 8 months after her first visit to our department. [ABSTRACT FROM AUTHOR]

Objectives: In patients with advanced oral squamous cell carcinoma (OSCC), surgical treatment is often administered in combination with radiotherapy-based postoperative adjuvant therapy. The aim of the present study was to determine the most appropriate dose by comparing patient outcomes between doses of 50- and 66-Gy for postoperative cervical irradiation.Materials and Methods: This retrospective study included patients who underwent postoperative cervical irradiation following neck dissection for OSCC with lymph nodes metastases, and their primary lesions were controlled. They were divided into the 50- and 66-Gy irradiation groups and were examined for sex, age, primary lesion site, tumor/node/metastasis stage, initial treatment for primary cancer, neck dissection procedure, number of metastatic lymph nodes, presence or absence of extranodal extension (ENE), concomitant anticancer agents, and therapeutic outcomes.Results: A total of 78 patients met the clinical criteria for study enrollment. The 50- and 66-Gy postoperative cervical irradiation groups included 40 and 38 patients, with neck dissection performed at 45 and 38 sites, respectively. Cervical control rate was 97.5% and 97.3% in the 50- and 66-Gy irradiation groups (p = 0.74). The cumulative disease-specific 5-year survival rate was 85.6% and 88.3%, respectively, with no significant difference (p = 0.64).Conclusion: The findings of our study indicate that the irradiation dose of 50 Gy is appropriate for postoperative cervical irradiation in patients with OSCC. [ABSTRACT FROM AUTHOR]