Autophagy inhibits TLR4-mediated invasiveness of oral cancer cells via the NF-κB pathway.

OBJECTIVES: Toll-like receptor 4 (TLR4) is abnormally expressed in oral cancer tissues and promotes cancer cell invasion. The purpose of this study was to clarify the mechanism by which autophagy regulates oral cancer invasion through the TLR4-NF-κB pathway. SUBJECTS AND METHODS: We examined TLR4 expression in oral cancer tissues and analysed the relationship between its expression and clinicopathological features. The invasion and migration of LPS-stimulated oral cancer cells with up- or downregulation of TLR4 expression was detected in addition to NF-κB signalling and autophagy levels. Furthermore, the role of autophagy in regulating TLR4-mediated cell invasiveness was explored by silencing the expression of key autophagy genes ATG7 and p62. RESULTS: We found that TLR4 overexpression was closely related to cervical lymphatic metastasis and poor survival. TLR4 activated the NF-κB pathway to promote the invasiveness of OSCC cells, and autophagy partly inhibited invasiveness by suppressing the NF-κB pathway. We observed that p62 translocated from the cytoplasm to the nucleus when autophagy was activated by LPS. Finally, silencing p62 further promoted LPS-mediated cell invasiveness. CONCLUSION: Toll-like receptor 4 significantly enhanced the invasiveness of OSCC cells. Autophagy may regulate cell invasiveness through the NF-κB pathway by modulating both the cytoplasmic and nuclear levels of p62.

Cone-beam computed tomography study of C-shaped root canal of mandibular premolars / 口腔疾病防治

Objective@#To investigate the incidence and morphology of C-shaped root canals in mandibular premolars by cone-beam computed tomography (CBCT) imaging, which provides a reference for clinical diagnosis and treatment.@*Methods @#The CBCT scanning data of 964 mandibular first premolars and 907 mandibular second premolars in 508 cases were collected, and the root canal morphology, incidence of C-shaped root canals, bilateral symmetry and location of radicular grooves were analyzed.@*Results@#The incidence of C-shaped root canals in mandibular first premolars was 4.1% and that in mandibular second premolars was 0.6%. The incidence of C-shaped root canals of mandibular first premolars was significantly higher than that of mandibular second premolars (χ2=25.775, P < 0.001). The symmetrical ratio of C-shaped root canals in the mandibular first premolars was 29%. There were no symmetrical C-shaped root canals in the mandibular second premolars. There were significant differences in the distribution of the C-shaped root canal configuration in the root canal (P < 0.001). The C-shaped configuration mainly existed in the middle axial and apical level of the mandibular premolars. The C2 type was more common. No C-shape was found in the coronal level of the mandibular premolars. Vertucci I single tube type was the most common type of root canal for the mandibular premolars included in this study; the incidences were 81.7% and 98.3% for the mandibular first and second premolars, respectively, and the difference was statistically significant (χ2=140.544, P < 0.001). The other root canal types of mandibular first premolars were more than those of mandibular second premolars. The incidences of Vertucci Ⅱ, Ⅲ, Ⅳ, and Ⅴ and C-shaped root canals in mandibular first premolars were significantly higher than those in mandibular second premolars. C-shaped root canal mandibular premolars had radicular grooves, and most of them were located at the mesiolingual side.@*Conclusion@# The morphology of the C-shaped root canal in mandibular premolars was complicated. CBCT can provide direct and accurate imaging evidence for clinical diagnosis and treatment.

A cone-beam computed tomography study of the root and canal morphology of maxillary premolars / 口腔疾病防治

Objective @# To study root morphology, the incidence of three root canals and the root canal anatomy of maxillary premolars.@*Methods@#The cone-beam computed tomography (CBCT) data of 779 maxillary first premolars and 728 maxillary second premolars were collected from 412 patients in Zhuhai Stomatological Hospital. The root and canal morphology, incidence of three canals, bilateral symmetry and location of root canal bifurcation were analyzed. @*Results @#The incidence of three canals in the maxillary first premolars was 1.8% and that in the maxillary second premolars was 0.3%. The incidence of three canals in the maxillary first premolars was significantly higher than that in the maxillary second premolars (c2=8.304, P=0.004). The symmetrical ratio of the three-canal maxillary first premolar was 27.3%. There was no symmetrical three-canal maxillary second premolar. The anatomical morphology of the maxillary premolar can be single root, double root or trident root. Its internal root canal system is complex and diverse. There are seven kinds of Vertucci morphology: the first maxillary premolar is mainly Vertucci IV type, and the second maxillary premolar is mainly Vertucci I type. Most of the root canal bifurcations of the three-canal maxillary premolars were observed in the midthird or the cervical third of the root. All three-canal maxillary premolars had three independent apical foramens. @*Conclusion @#The root canal morphology of maxillary premolars is complex and changeable. CBCT plays an important role in the discovery of variation and extra root canals.

Selective Versus Comprehensive Neck Dissection in Patients With T1 and T2 Oral Squamous Cell Carcinoma and cN0pN(+) Neck.

PURPOSE: There is still no consensus on the oncologic safety of selective neck dissection (SND) in the management of pathologically positive neck in patients with oral squamous cell carcinoma (OSCC). This study compared the clinical outcome between SND and comprehensive neck dissection (CND) for patients with T1 and T2 OSCC and a clinically negative but pathologically positive neck. MATERIALS AND METHODS: Retrospective study of medical records of patients with T1 and T2 OSCC and clinical N0 but pathologic N(+) disease from March 2000 through March 2011 was performed. Thirty-seven patients underwent SND or CND. Median follow-up was 51 months. Regional control and disease-specific survival rates were statistically analyzed. RESULTS: No significant differences in 3-year ipsilateral neck control rate (81.8 vs 91.7%; P = .590 by log-rank test) and overall regional control rate (72.7 vs 86.8%; P = .424 by log-rank test) were found between the SND and CND groups. Three-year disease-specific survival rates of the SND and CND groups were 72.7 and 82.1%, respectively. No significant difference was found between these 2 groups by log-rank test (P = .428). CONCLUSIONS: The results indicate that SND in conjunction with postoperative radiotherapy is effective in the management of patients with T1 and T2 OSCC and cN0pN(+) neck.

A meta-analysis on selective versus comprehensive neck dissection in oral squamous cell carcinoma patients with clinically node-positive neck.

OBJECTIVE: Properly management of cervical lymph node metastases is a critical treatment for patients with oral squamous cell carcinoma (OSCC). However there is no consensus on the optimal treatment for oral cancer patients with clinically node-positive (cN+) neck. This study aims to access the feasibility of selective neck dissection in oral cancer patients with cN+neck. METHOD: We searched PubMed and EMBASE up to April 2015 to identify the studies which compared selective neck dissection (SND) with comprehensive neck dissection (CND) in OSCC patients with cN+neck. Data were extracted by two authors. The meta-analysis was conducted with regional recurrence and disease specific death as primary endpoints. RESULT: Five studies with a total of 443 patients met our inclusion criteria. No significant difference was found regarding regional recurrence, disease specific death or overall death between the SND and CND group. CONCLUSION: These findings suggest that cN+OSCC patients treated with SND in conjunction with adjuvant therapy got comparable clinical outcome to CND.