Sialendoscopic removal of metastatic adenocarcinoma in a mucous plug from Stensen's duct.

Sialendoscopy is a minimally invasive technique used mainly in the diagnosis and treatment of obstructive salivary gland disorders. There has yet to be a report on its use in the diagnosis of metastatic disease. While metastatic cancer has been described in numerous head and neck anatomic subsites, it has not been reported to be found in a mucous plug in Stensen's duct. Sialendoscopy was performed in a 68-year-old female patient who presented with symptoms of ductal obstruction. Basket removal of a mucous plug was done and histopathological analysis of this specimen found adenocarcinoma. The overall clinical picture, imaging, and final histopathological results suggested that this patient had metastatic breast carcinoma to a mucous plug in Stensen's duct, the diagnosis of which was made with the aid of interventional sialendoscopy. This is the first report in which metastatic cancer was identified in a mucous plug in Stensen's duct. Sialendoscopy can be a useful tool to aid in the diagnosis of metastatic diseases in rare and unusual clinical situations.

Optimization of total tongue functional reconstruction with the sushi roll technique and its application in pectoralis major myocutaneous flaps.

A protuberant shape and sufficient volume are the most important parameters for total tongue reconstruction. The conventional pectoralis major myocutaneous (PMMC) flap undergoes collapse due to atrophy of the denervated muscle. In a new technique, this flap was rolled up like sushi to reshape the neotongue. This study explored the feasibility and effect of the 'sushi roll' technique for precise total functional reconstruction of the tongue using a PMMC flap. Thirty patients scheduled for total glossectomy and PMMC flap reconstruction were recruited. The sushi roll technique was performed in 15 patients and the conventional repair in 15 patients. Outcomes were compared between the two groups. The flap survived in all 30 patients. The sushi roll group showed superior results to the conventional group in terms of time to oral alimentation (P = 0.012) and decannulation (P = 0.041), as well as swallowing function (P = 0.032), speech intelligibility (P < 0.001), shape (P < 0.001), and quality of life score (P < 0.001) at 12 months. The innovative sushi roll technique uses a folding method that utilizes the length rather than the thickness and width of the flap to maintain the volume and protuberance of the neotongue, which results in acceptable function and improved quality of life.

Spatial deviations of the temporomandibular joint after oncological mandibular reconstruction.

Spatial deviations of the temporomandibular joint (TMJ) after oncological mandibular reconstruction are important to the aesthetic and functional rehabilitation. The aim of this study was to clarify whether and how three dimensionally (3D) printed patient-specific surgical plates, and the preservation of the condyle or ramus, affect spatial deviations of the TMJ. A total of 33 patients who underwent mandibular reconstruction via computer-assisted surgery were included. Regarding absolute deviations, patients in the 3D-printed plate group showed smaller TMJ deviations compared to those in the conventional plate group. There was no difference in absolute deviations of the TMJ regardless of whether the condyle or ramus was preserved. Regarding physiological deviations, the impact on the contralateral TMJ was smaller in the 3D-printed plate group. Patients with both the condyle and ramus removed had significantly higher deviations of the condyle and joint space. In summary, 3D-printed patient-specific surgical plates improved the spatial accuracy of the TMJ. Under physiological conditions, TMJ deviations on the operated side were mainly affected by the preservation of the condyle. Removal of both the condyle and ramus caused more severe spatial interference to the TMJ; this should be further confirmed.

Prediction of ameloblastoma recurrence using random forest-a machine learning algorithm.

The purpose of this study was to investigate whether ameloblastoma with a high likelihood of recurrence can be predicted using random forest model, a machine learning algorithm. Data were collected from patients treated for ameloblastoma between 1999 and 2019 at the University of Hong Kong. Fourteen clinical parameters were used to grow the decision trees to classify patients with or without ameloblastoma recurrence in the follow-up period. The random forest algorithm was computed 100 times in the training cohort (n = 100) and verified in the testing cohort (n = 50). The receiver operating characteristic curve (ROC) and area under the curve (AUC) were used as the performance measurement of separability. One hundred and fifty patients (76 female, 74 male) were recruited, with a mean follow-up time of 103 months. Recurrence occurred in a total of 25 cases (16.7%) over the 20-year period. The AUC were calculated for the median and mean ROC curves; these were 0.777 and 0.825, respectively. The results showed that random forest model was able to predict recurrence of ameloblastoma with reliable accuracy. The four most important variables influencing ameloblastoma recurrence were the time elapsed from treatment, initial surgical treatment, tumour size, and radiographic presentation. This study provides insights into the detection of high-risk patient groups to monitor recurrence. Further application of random forest to other diseases could greatly benefit clinical decisions.

Surgical morbidities of sagittal split ramus osteotomy versus intraoral vertical ramus osteotomy for the correction of mandibular prognathism: a randomized clinical trial.

The sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) are two common orthognathic procedures for the treatment of mandibular prognathism. This randomized clinical trial compared the surgical morbidities between SSRO and IVRO for patients with mandibular prognathism over the first 2 years postoperative. Ninety-eight patients (40 male, 58 female) with a mean age of 24.4±3.5 years underwent bilateral SSRO (98 sides) or IVRO (98 sides) as part or all of their orthognathic surgery. IVRO presented less short-term and long-term surgical morbidity in general. The SSRO group had a greater incidence of inferior alveolar nerve deficit at all follow-up time points (P< 0.01). There was more TMJ pain at 6 weeks (P= 0.047) and 3 months (P= 0.001) postoperative in the SSRO group. The SSRO group also presented more minor complications, which were related to titanium plate exposure and infection. There were no major complications for either technique in this study. Despite the need for intermaxillary fixation, IVRO appears to be associated with less surgical morbidity than SSRO when performed as a mandibular setback procedure to treat mandibular prognathism.

Reliable ductal access in sialoendoscopy.

During sialoendoscopy, insertion of the endoscope through the ductal orifice is usually a challenging procedure, especially for beginners. Based on our experience, we have found that using the Kolenda Salivary Access Introducer Set is the most reliable and easily learned ductal access approach. We report details of the technique and discuss the advantages of this approach.

Genomic Signature of Mismatch Repair Deficiency in Areca Nut-Related Oral Cancer.

Areca nut (AN) chewing contributes to an increase of oral squamous cell carcinoma (OSCC) cases in South and Southeast Asia; however, genomic events underlying the carcinogenesis process of AN-related OSCC remain unclear. Here, we comprehensively describe the genomic and transcriptome alterations of 113 Chinese OSCC patients (89 AN related and 24 AN negative) by whole-exome sequencing and RNA sequencing, and we compared the genomic differences between AN-related and AN-negative samples by integrating sequencing data of 325 OSCC patients from The Cancer Genome Atlas database and 50 from a published Taiwanese study. We identified 11 significantly mutated genes for OSCC, including 4 novel ones (ATG2A, WEE1, DST, and TSC2), of which WEE1 and ATG2A mutated with significantly higher rates in AN-related samples (P = 0.04 and P = 0.003, respectively). Mutational signature analysis revealed that AN-related OSCCs were specially characterized by the genomic signature of mismatch repair deficiency (dMMR), which could also predict the prognosis status of AN-related OSCC. In addition, an elevated PD-L1 expression was also observed in both AN-related patients (P = 3.71 × 10-11) and those with a high dMMR level (P = 1.99 × 10-4). Further differential expression analysis and in vitro experiments confirmed the role of dMMR in the development of OSCC induced by AN exposure. Taken together, this study first revealed the molecular profiles and highlighted the role of dMMR in AN-related OSCC among the Chinese population and identified that AN-related OSCC may represent a potential cohort for effective anti-PD-1/L1 immunotherapy.

[Co-prevalence relationship analysis on different metabolic syndrome scores and behavioral risk factors in adults from Urumqi based].

Objective: To investigate the influence of the prevalence and co-prevalence of risk factors for metabolic syndrome on the scores of different levels of metabolic syndrome in people receiving physical examination in Urumqi. Methods: Using the 2017 Xinjiang Health Examination Database, a total of 175 927 people from 7 districts and 1 county in Urumqi were selected as subjects. Face-to-face survey and body measurements were used to collect cardiovascular risk factors and metabolic syndrome scores. Metabolic syndrome scores were used. For the 0-5 points at 6 levels, χ(2), χ(2) trend test, correlation analysis of ordered variable Kendall's tau-b, and logistic regression analysis of ordered results were used to analyze the influence of prevalence and co-prevalence of behavioral risk factors on the MS scores. Results: The percentages of 6 metabolic syndrome scores in the sample population were 23.82%, 27.87%, 22.41%, 16.03%, 8.02%, and 1.85%, respectively. The scores of metabolic syndrome were different in different age groups, ethnic groups, groups with different drinking rates, and groups with different dietary types, with the differences all significant (P<0.05).The MS score in men increased with the increase of oil/salt rate and excessive drinking rate (P<0.01). The score in women increased with the increase of the current smoking rate, oil/salt rate, and increased with the decrease of physical activity (P≤0.01). There was no significant difference in the distribution of regular drinking rates between different score groups (P>0.05). The scores of metabolic syndrome increased with the increase of risk factors (P<0.05). Ordered results logistic analysis found that in the men with ≥3 risk factors and the metabolic syndrome score was 1.15 (1.06-1.26) times higher than that in the men without risk factor, as well as in women with 2 risk factors and≥3 risk factors. The metabolic syndrome scores were 1.38 (1.22-1.55), 2.02 (1.53-2.66) times higher than those in the women without risk factors. Conclusions: The physical examination group in Urumqi, the more the metabolic syndrome disease behavior risk factors clustered, the higher the metabolic syndrome score was. Therefore, comprehensive intervention measures should be taken to control the different forms of metabolic syndrome to prevent the occurrence and progress of the disease.

Oral Epstein-Barr virus-positive mucocutaneous ulcer: gingival presentation of a benign lymphoproliferative lesion.

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a benign lymphoproliferative lesion related to iatrogenic or age-related immunosuppression in patients with prior Epstein-Barr virus (EBV) infection. Although the clinical presentation may resemble malignant disease, the course of EBVMCU is indolent, and regression is expected when immunosuppression is reduced. We present a case of EBVMCU in the gingiva of a 59-year-old male patient with long-standing pemphigus vulgaris. The initial presentation was suspicious for oral cavity cancer, which was ruled out by biopsy. After reduction of immunosuppression, the ulceration regressed and an area of exposed necrotic bone remained. Complete healing was achieved after sequestrectomy and primary closure with a local gingival flap.

"One-piece" patient-specific reconstruction plate for double-barrel fibula-based mandibular reconstruction.

Segmental mandibular defects require reconstruction. The fibula flap serves as a versatile flap in restoring mandibular contour and bony height. With the advances in computer-aided design and additive manufacturing technology, an innovative "one-piece" patient-specific reconstruction plate to facilitate double-barrel fibula flap shaping and bone securing was developed; the plate is described in this study. The "one-piece" plate is fabricated with individualized specifications and is mainly composed of three components: the long-bar reconstruction plate, a short-bar plate, and connecting bars. Our initial experiences showed that mandibular reconstructive surgery was greatly facilitated by the "one-piece" reconstruction plate for double-barrel fibula flap reconstruction and achieved satisfactory outcomes. A well-designed clinical trial is required to confirm the superiority of the "one-piece" reconstruction plate in the future. ClinicalTrials.gov registration: NCT03057223.

[Malfunction of autophagy in tibial growth plate chondrocytes causes increased apoptosis rate in chronic renal insufficiency rats].

Objective: To observe the effect of autophagy of tibial growth plate chondrocyte on apoptosis in chronic renal insufficiency (CRI) rats. Methods: Male 4-week-old SD rats were randomly divided into two groups: (1) Sham group: only the left ureter was exposed (n=10); (2) CRI group: the left ureter was ligated to cause CRI (n=10). The urine from all the rats was collected 6 weeks after the operation and the total protein content was measured. Then all the rats were sacrificed and the concentrations of creatinine and urea nitrogen in intracardiac blood were detected. The proximal tibia were fixed and decalcified to prepare histological sections, and the number of chondrocytes of column cells in the proliferative area of tibia growth plate was observed by saffron O staining. The expression rate of protein Light Chain-3, an autophagy marker of chondrocytes, was detected by immunofluorescence. The apoptosis rate of chondrocytes was detected by the method of TUNEL assay. The level of glycogenin-1, a glycogen formation marker of chondrocyte was detected by immunohistochemistry in chondrocytes. Results: The 24 h urine total protein was higher in CRI group [(163.5±11.3) mg vs (38.6±9.8) mg, t=25.620, P<0.001]. The levels of blood creatinine [(67.3±16.2) µmol/L vs (28.4±11.5) µmol/L, t=5.974, P<0.001] and urea nitrogen [(16.4±6.4) mmol/L vs (4.8±2.0) mmol/L, t=5.198, P<0.001] were higher in CRI group. The number of chondrocytes of column cells in the proliferating area of tibia growth plate was lower in CRI group (4.2±2.1 vs 9.1±3.8, t=3.109, P=0.006). The expression rate of LC-3 protein in chondrocytes of CRI group was lower [(27.2±12.6)% vs (51.4±18.2)%, t=3.457, P=0.003]. The level of glycogenin-1 of chondrocytes in CRI group increased significantly (6.1±2.5 vs 3.5±1.8, t=2.669, P=0.016). The apoptosis rate of chondrocytes in CRI group also increased [(17.2±4.8)% vs (5.1±3.4)%, t=6.505, P<0.001]. Conclusion: Malfunction of autophagy in tibial growth plate chondrocytes causes increased apoptosis rate in CRI rats, which might be caused by the failure of glycogen degradation in chondrocytes.

A novel 'surgeon-dominated' approach to the design of 3D-printed patient-specific surgical plates in mandibular reconstruction: a proof-of-concept study.

Three-dimensionally (3D) printed patient-specific surgical plates have been proposed to facilitate mandibular reconstruction and are attracting extensive attention. We have recently reported the high accuracy of 3D-printed patient-specific surgical plates used in head and neck reconstruction. Based on this previous work, the current study proposes a novel 'surgeon-dominated' approach to the design of 3D-printed patient-specific surgical plates. The aim of this proof-of-concept study was to explore the workflow and technical procedures of the surgeon-dominated approach. The workflow includes virtual surgery, the design and printing of patient-specific surgical devices, and real surgery. The prototype of the patient-specific surgical plate was designed by surgeons and further optimized for 3D printing by engineers. Different types of mandibular defect were tested to confirm the wide applicability of this approach. Cases in which this approach was used were reviewed and the duration of time spent on each case studied. Based on a total of 16 patients, the time spent on virtual surgery and plate design was 18.83±13.19hours, and the time taken for 3D printing, post-processing, and product delivery was 162.9±55.15hours. Therefore, this novel surgeon-dominated approach is feasible and time-saving, which would likely promote the wide application of patient-specific surgical plates and lead to a new era of 'digitization and precision' in mandibular reconstruction. ClinicalTrials.gov registration: NCT03057223.

Assessment of the contralateral facial artery pedicle nasolabial island flap for buccal defect repair.

The facial artery pedicle nasolabial island flap (FAPNIF) is widely used for oral and maxillofacial reconstruction. However, its use in reconstruction after malignant tumour resection is limited by the possibility of ipsilateral cervical lymph node metastasis along the facial artery. Through fine dissection, it was found that the contralateral FAPNIF can be used to repair the defect after buccal carcinoma resection. The aim of this study was to evaluate the clinical outcomes of the contralateral FAPNIF for buccal defect repair. From 2013 to 2016, 30 patients underwent the repair of a buccal defect with a contralateral FAPNIF after tumour resection. Clinical outcomes and complications were recorded and quality of life was evaluated preoperatively and at 3, 6, and 12 months postoperative. The flaps survived in all 30 cases. Mean mouth opening was 2.50±0.14cm at 1 month, 3.22±0.25cm at 6 months, and 3.35±0.23cm at 12 months postoperative. With regard to patient quality of life, adverse effects included impaired aesthetics, pain, and difficulty eating; these usually subsided within 1year after surgery. The contralateral FAPNIF is easily harvested and is a safe and effective option for the repair of medium-sized buccal defects after the resection of carcinoma.

[Effect of primary cilia expression rate on Wnt/ß signaling pathway in tibial growth plate chondrocytes from chronic renal insufficiency young rats].

Objective: To observe the effect of primary cilia expression rate on Wnt/ß signaling pathway in tibial growth plate chondrocytes from chronic renal insufficiency (CRI) young rats. Methods: Male 2-week-old SD rats were randomly divided into two groups: (1) Sham group: only the left ureter was exposed (n=6); (2) CRI group: the left ureter was ligated (n=6). Rats were sacrificed 2 weeks after the operation and the primary cilia expression rate of growth plate chondrocytes and key protein ß-catenin in Wnt/ß signaling pathway were observed in histological section of tibia specimen. Chondrocytes isolated from growth plate in two groups were cultured in vitro to P3 generation. The primary cilia expression rate and the level of ß-catenin were measured. The primary cilia expression rate was detected by agonists and antagonists Wnt/ß signaling pathway in chondrocytes of CRI group. The level of ß-catenin was detected by using serum-free culture and chloral hydrate to intervene chondrocytes in CRI group. Results: The primary cilia expression rate of growth plate chondrocytes in histological section of tibia specimen in CRI group was higher than that in Sham group [(17.5±7.7)% vs (8.7±3.6)%, t=3.237, P=0.005], and the level of ß-catenin was higher in CRI group (5.1±0.7 vs 1.9±0.8, t=6.731, P<0.001). The primary cilia expression rate of growth plate chondrocytes cultured in vitro in CRI group was higher than that in Sham group [(20.9±8.1)% vs (11.8±4.7)%, t=3.073, P=0.007], and the level of ß-catenin was higher in CRI group (0.49±0.12 vs 0.25±0.11, t=3.297, P=0.011). There was no significant change in primary cilia expression rate after intervention by using Wnt/ß signaling agonists and antagonists to change the level of ß-catenin [agonists group: (21.3±7.6)%, control: (20.6±6.8)%, antagonists group: (22.4±6.2)%, F=0.173, P=0.842]. The level of ß-catenin was significantly changed after intervention by using serum-free culture, chloral hydrate to alter the primary cilia expression rate (serum-free culture group: 0.61±0.23, control: 0.39±0.24, chloral hydrate group: 0.15±0.11, F=6.476, P=0.012). There was a positive correlation between the level of ß-catenin and primary cilia expression rate. Conclusion: The primary cilia expression rate and the level of Wnt/ß signaling pathway were higher in tibial growth plate chondrocytes in CRI rats model, and primary cilia might have positive regulatory effects on the Wnt/ß signaling pathway.

[Effect of low expression of PTHrp receptor on proliferation of tibial growth plate chondrocytes in chronic renal insufficiency young rats].

Objective: To observe the effect of parathyroid hormone-related protein (PTHrp) receptor on the proliferation of tibial growth plate chondrocytes in chronic renal insufficiency (CRI) young rats. Methods: Two-week-old male SD rats were randomly divided into two groups: (1) Sham group (n=6), only left ureter was exposed; (2) CRI group(n=6), left ureter was ligated to induce chronic renal insufficiency. Rats were sacrificed 2 weeks after operation and the blood concentration of PTHrp was detected by intracardiac blood sampling. Chondrocytes isolated from growth plate in two groups were cultured in vitro to P3 generation. The level of PTHrp receptor in chondrocytes was observed by immunohistochemistry and quantitative analysis was completed by Western blot. The proliferation rate of chondrocytes from two groups at 24 h was detected by using 5-ethynyl-2'-deoxyuridine (EDU) technique. Three types of PTHrp receptor mRNA plasmids (overexpressed, empty vector and knockdown) were used to treat the chondrocytes from CRI group. The mRNA and protein levels of PTHrp receptor were detected after 24 h and 48 h intervention, respectively. The chondrocyte proliferation rate at 24 h was detected by EDU. Results: Blood concentration of PTHrp in CRI group was higher than that in Sham group [(1.36±0.42) ng/L vs (0.77±0.21) ng/L, t=3.913, P=0.001]. The results of Western blot showed that the level of PTHrp receptor in growth plate chondrocytes from CRI group decreased (0.15±0.07 vs 0.41±0.13, t=5.569, P<0.001). Chondrocyte proliferation rate of CRI group was lower than that in Sham group at 24 h [(11.3±3.1)% vs (24.6±5.7)%, t=6.482, P<0.001]. The mRNA and protein levels of PTHrp receptor increased in chondrocytes of CRI group after intervention with overexpressed plasmid. The chondrocyte proliferation rate increased at 24 h. On the contrary, the mRNA and protein levels of PTHrp receptor decreased afer intervention with knockdown plasmid, and the chondrocyte proliferation rate also decreased [overexpression: (22.8±6.5)%, empty carrier: (10.2±4.3)%, knockdown: (5.6±2.1)%, F=29.840, P<0.001]. Conclusion: Increased PTHrp concentration in the blood of CRI young rats leads to decreased PTHrp receptors in growth plate chondrocytes, which results in decreasing PTHrp activity and proliferation rate of chondrocyte.

[Effect of primary cilia on growth plate chondrocyte proliferation of young rats with chronic renal insufficiency].

Objective: To observe the effect of primary cilia on growth plate chondrocyte proliferation of young rats with chronic renal insufficiency (CRI). Methods: Male 2-week-old Sprague-Dawley rats were randomly divided into two groups (with 10 in each group): Sham group (only left ureter was exposed) and CRI group (left ureter was ligated). Rats were sacrificed 2 weeks after operation and the total length of tibia was measured. Histological sections of tibia were taken to observe the chondrocytes of growth plate proliferative region and the expression rate of primary cilia. Chondrocytes from growth plate in two groups were isolated and cultured in vitro to P3 generation and the chondrocyte proliferation rate at 24 h were detected. The primary cilia expression rate and cilia length of chondrocytes were measured. Western blot was used to detect the expression of intraflagellar transport 88 (IFT88) protein and the gray scale was analyzed. Results: The total length of tibia was shorter in CRI group [(35.84±4.56) mm vs (42.33±3.44) mm, P=0.002]. The results of tibial histological section showed that chondrocytes of growth plate proliferative region were unorganized and the number of chondrocyte with columnar structure was less in CRI group (2.71±1.10 vs 7.68±1.32, P<0.001). The primary cilia expression rate of chondrocytes was higher in CRI group [(35.53±7.41)% vs (18.31±5.12)%, P<0.001]. The chondrocyte proliferation rate at 24 h was lower in CRI group [(11.38±6.10)% vs (24.35±8.46)%, P=0.001]. The primary cilia expression rate of chondrocytes was higher in CRI group [(60.12±7.86)% vs (32.17±8.97)%, P<0.001], and the primary cilia length of chondrocytes was longer in CRI group [(3.54±1.61) µm vs (1.96±0.82) µm, P=0.012]. The protein IFT88 was more highly expressed in CRI group (0.47±0.23 vs 0.17±0.10, P=0.001). Conclusion: The primary cilia expression rate of growth plate chondrocytes was higher in the rats with CRI, resulting in decreased chondrocyte proliferation rate and growth retardation of tibial growth plate.

Risk factors for recurrence of ameloblastoma: a long-term follow-up retrospective study.

Ameloblastoma is a benign odontogenic tumour showing locally aggressive characteristics. This retrospective study was performed to investigate the long-term treatment outcomes of ameloblastoma and to evaluate the risk factors for recurrence. The study was conducted in the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, the University of Hong Kong and covered the years 1990-2017. Patient demographic data, radiographic pattern and findings, clinical findings, tumour site and size, World Health Organization classification, treatment modality, histological pattern, duration of follow-up, and timing of recurrence were recorded and analyzed. The potential risk factors were analyzed by Kaplan-Meier and Cox regression tests. The cases of a total of 128 patients were reviewed; 65 were male and 63 were female. The mean follow-up period was 117 months. The 5-, 10-, and 15-year recurrence rates were 9.3%, 17.6%, and 24.4%, respectively. Kaplan-Meier and Cox regression tests showed that recurrence was significantly associated with radiographic pattern, tumour size, and treatment modality. Multiple regression analysis for these three variables demonstrated that treatment modality was the only independent prognostic factor for recurrence. This study showed that radical resection is the only significant factor for a low recurrence rate of ameloblastoma and patients require long-term follow-up for late-onset recurrence.

Effects of Salivary Mg on Head and Neck Carcinoma via TRPM7.

Magnesium (Mg) has been known to play vital roles in regulating growth and various metabolic processes. In recent years, the association between Mg and tumorigenesis has raised more and more attention. However, the effects of Mg on the progression of head and neck carcinoma (HNC), as well as the mechanism behind it, remain undefined. In this study, the roles of Mg in tumorigenic activities were tested in CAL27 and FaDu cells as well as in a xenograft tumor model in nude mice. We demonstrated that a moderate increase in extracellular Mg contributed to the proliferation, migration, and invasion of 2 HNC cell lines, while the addition of Mg in drinking water promoted the growth of xenograft tumors in mice without altering their serum Mg levels. Moreover, TRPM7, a major Mg transporter, was shown to be essential for the tumorigenic activities of HNC and the Mg-induced promotive effects on HNC cells and was further shown to be associated with the activation of AKT/mTOR (mammalian target of rapamycin) signaling. In a preliminary clinical study, we determined the Mg ion concentrations in the stimulated saliva from 72 patients with nasopharynx carcinoma and 12 healthy individuals. Our data revealed that the salivary Mg levels of subjects with nasopharynx carcinoma were significantly higher than those of the healthy controls. This is correlated with our finding showing TRPM7 to be overexpressed in tumor tissues harvested from 9 patients with HNC. Therefore, we can conclude that salivary Mg level, within a certain range, could act as a risk factor for the progression of HNC, which involves the activation of AKT/mTOR signaling pathways through the TRPM7 channel. The control of salivary Mg level and the intervention of TRPM7 should not be ignored during the study of HNC.