The interaction and mediation effects between the host genetic factors and Epstein-Barr virus VCA-IgA in the risk of nasopharyngeal carcinoma.

Previous studies have demonstrated strong associations between host genetic factors and Epstein-Barr virus (EBV) VCA-IgA with the risk of nasopharyngeal carcinoma (NPC). However, the specific interplay between host genetics and EBV VCA-IgA on NPC risk is not well understood. In this two-stage case-control study (N = 4804), we utilized interaction and mediation analysis to investigate the interplay between host genetics (genome-wide association study-derived polygenic risk score [PRS]) and EBV VCA-IgA antibody level in the NPC risk. We employed a four-way decomposition analysis to assess the extent to which the genetic effect on NPC risk is mediated by or interacts with EBV VCA-IgA. We consistently found a significant interaction between the PRS and EBV VCA-IgA on NPC risk (discovery population: synergy index [SI] = 2.39, 95% confidence interval [CI] = 1.85-3.10; replication population: SI = 3.10, 95% CI = 2.17-4.44; all pinteraction < 0.001). Moreover, the genetic variants included in the PRS demonstrated similar interactions with EBV VCA-IgA antibody. We also observed an obvious dose-response relationship between the PRS and EBV VCA-IgA antibody on NPC risk (all ptrend < 0.001). Furthermore, our decomposition analysis revealed that a substantial proportion (approximately 90%) of the genetic effects on NPC risk could be attributed to host genetic-EBV interaction, while the risk effects mediated by EBV VCA-IgA antibody were weak and statistically insignificant. Our study provides compelling evidence for an interaction between host genetics and EBV VCA-IgA antibody in the development of NPC. These findings emphasize the importance of implementing measures to control EBV infection as a crucial strategy for effectively preventing NPC, particularly in individuals at high genetic risk.

Machine learning-based models for predicting gas breakthrough pressure of porous media with low/ultra-low permeability.

Gas breakthrough pressure is a significant parameter for the gas exploration and safety evaluation of engineering barrier systems in the carbon dioxide storage, remediation of contaminated sites, and deep geological repository for disposal of high-level nuclear waste, etc. Test for determining gas breakthrough pressure is very difficult and time-consuming, due to the low/ultra-low conductivity of the specimen. It is also difficult to get a comprehensive and high-precision model based on limited results obtained through individual experiments, as the measurements of gas breakthrough pressure were influenced by many factors. In this study, a collected database was built that covered a lot of former test data, and then, two models were developed by the random forest (RF) algorithm and multiexpression programming (MEP) method. The MEP model constructed with explicit expressions for the gas breakthrough pressure overcame the drawbacks of common "black box" models. Meanwhile, five significant indicators were selected from ten common features using the permutation importance algorithm. The RF model was interpreted by the Shapley value and the PDP/ICE plots, while the MEP model was analyzed through the proposed explicit expression, showing strong consistence with that in former studies. Finally, robustness analysis was conducted, and stability of the proposed two models was verified.

Analysis of Immunological Characteristics and Genomic Alterations in HPV-Positive Oropharyngeal Squamous Cell Carcinoma Based on PD-L1 Expression.

Programmed death-ligand 1 (PD-L1) expression has been approved as an immune checkpoint inhibitor (ICI) response predictive biomarker; however, the clinicopathological and molecular features of HPV-positive oropharyngeal squamous cell carcinoma [HPV(+)OPSCC] based on PD-L1 expression are not well studied. We aimed to characterize clinicopathological, tumor immune microenvironmental, and molecular features of HPV(+)OPSCC with different PD-L1 expression scored by combined positive score (CPS). A total of 112 cases were collected from 2008-2021 and received PD-L1 and CD8 immunohistochemistry (IHC) staining. 71 samples received DNA sequencing out of which 32 samples received RNA sequencing for immune-related gene alterations or expression analysis. The 32 samples were also subjected to analysis of CD20, CD4, CD8, CD68, Foxp3 and P16 by multiplex immunofluorescence (mIF) staining, and the immune markers were evaluated in the tumor body (TB), tumor margin (TM) and normal stroma (NS) regions separately. Our results showed that of 112 HPV(+)OPSCC tumors, high(CPS≥20), intermediate(1≤CPS<20), and low(CPS<1) PD-L1 expression was seen in 29.5%, 43.8% and 26.8% cases respectively. Non-smoking patients and patients with tumors occurring at the tonsils or having rich lymphocytes infiltration had significantly higher PD-L1 expression. Patients with CPS≥20 had significantly higher tumor mutation burden (TMB, p=0.0058), and PD-L1 expression correlated significantly with CD8+ T cells infiltration, which were ample in tumor regions than in NS in mIF. CD20+, CD4+, CD68+, Foxp3+CD4+ cells were demonstrated to infiltrate higher in TM while CD20+ and CD68+ cells were also enriched in NS and TB regions respectively. However, none of them showed correlations with PD-L1 expression. ARID1A, STK11 alterations were enriched in the low PD-L1 group significantly, while anti-viral immune associated APOBEC mutation signature and immune-related genes expression such as XCL1 and IL11 were positively associated with PD-L1 expression (p<0.05). This is a comprehensive investigation revealing immune and molecular features of HPV(+)OPSCC based on PD-L1 expression. Our study suggested that 73.2% of HPV(+)OPSCC patients may benefit from immunotherapy, and high PD-L1 expression reflects immune-active status of HPV(+)OPSCC accompanied by higher immune effect factors such as TMB, CD8+ cytotoxic T cells and immune-related genomic alterations. Our study offers valuable information for understanding the immune features of HPV(+)OPSCC.

Calcitonin gene-related peptide enhances osteogenic differentiation and recruitment of bone marrow mesenchymal stem cells in rats.

The present study evaluated the effects of calcitonin gene-related peptide (CGRP) on bone marrow mesenchymal stem cells (BMMSCs) in vitro and in a rat model of mandibular distraction osteogenesis (MDO). Rat BMMSCs were isolated then treated with CGRP or CGRP antagonist (CGRP8-37). The proliferation and migration ability of BMMSCs was determined using 5-bromo-2'-deoxyuridine and Transwell assays, respectively. Osteogenic-related gene expression was analyzed with reverse transcription-quantitative polymerase chain reaction. For the in vivo analysis, thirty MDO rats were randomly assigned to control, CGRP or CGRP8-37 groups. To evaluate the mobilization of BMMSCs, nestin and stromal cell-derived factor 1 (SDF-1) were detected by immunohistochemistry and ELISA. Rats were sacrificed following 14 days and new bone formation was assessed by histological and micro-computed tomography analysis. In the in vitro results, the CGRP group demonstrated significantly higher migration and proliferation, as well as enhanced alkaline phosphatase and runt-related transcription factor 2 expression compared with the control. In the in vivo experiments, bone mineral density of the newly formed bone in the CGRP group was significantly higher than controls. The nestin and SDF-1 expression in the CGRP group was also significantly upregulated. In conclusion, the present study demonstrated that CGRP administration increased new bone formation, possibly via enhancing BMMSC migration and differentiation in MDO rats.

Application of Computed Tomography Angiography Mapping and Located Template for Accurate Location of Perforator in Head and Neck Reconstruction with Anterolateral Thigh Perforator Flap.

BACKGROUND: The authors introduce a new method of preoperative computed tomography angiography mapping and virtual and printed located template for accurate location of perforators in the anterolateral thigh perforator flap for head and neck reconstruction. METHODS: Between April and December of 2014, a cohort study was performed with 29 patients who underwent head and neck reconstruction with anterolateral thigh perforator flaps. Computed tomography angiography images were processed for maximum intensity projection and volume rendering to obtain and evaluate the perforator information. The virtual and printed templates with grid were used to transfer the perforator information for intraoperative guidance during flap harvest. The preoperative angiography results were compared with the high-frequency color Doppler results and with the intraoperative real-time findings to evaluate the accuracy of computed tomography angiography mapping. RESULTS: The source vessel, origin, location, direction, number, and caliber of the perforators were determined by preoperative computed tomography angiography mapping. All of the perforator data were accurately mapped on a virtual template and printed on the located template to guide flap harvest. The flap was actually used and survived successfully in 20 patients. The results for perforators identified by mapping were more accurate than those for perforators identified by Doppler. There was no significant difference between the preoperative computed tomography angiography results and the intraoperative findings (p > 0.05). CONCLUSIONS: The role of preoperative computed tomography angiography mapping in guiding anterolateral thigh perforator flap harvest and reducing the unpredictable risk of surgery is acceptable. Located virtual and printed template with grid can transform preoperative computed tomography angiography information to the intraoperative setting accurately and easily. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.

STAT3 is a key pathway in primary intraosseous squamous cell carcinoma arising from an odontogenic keratocyst.

PURPOSE: Primary intraosseous squamous cell carcinoma (PIOSCC) arising within an odontogenic keratocyst (OKC) is rare malignancy, entailing a poor prognosis for delayed diagnosis. The number of reports concerning this entity is extremely small. The aim of this study is to present the clinical and pathologic characteristics of PIOSCC and investigate its pathogenesis. MATERIALS AND METHODS: This study describes three patients with mandibular PIOSCC derived from an OKC over a seven-year period, each of which suffering from decompression in mandible. Important diagnostic criteria included the absence of overlying oral mucosal ulceration, the absence of a distant potential primary tumor, and the presence of a completely intraosseus lesion. The malignant transformation of OKC to PIOSCC was confirmed by pathologic evaluation of surgical resection specimens. Immunohistochemistry (IHC) was used to evaluating expression of Ki-67, p65, EGFR, phospho-AKT, and STAT3 in each of the three tumors and adjacent cyst walls. RESULTS: Analysis by IHC indicated that Ki67, P65, EGFR and STAT3 were substantially elevated in PIOSCC. There was an obvious positive correlation between Ki67, P65, EGFR and STAT3 expression in adjacent benign epithelium. Each tumor exhibited long-standing chronic inflammation in the benign odontogenic cyst, suggesting that a sustained immune response may be partially responsible for malignant transformation of the benign cystic lining cells. CONCLUSIONS: These findings indicate that inflammation may be the principal mediator in PIOSCC ex-OKC, and the STAT3 signaling pathway is an important contributor to this process. Combined detection of Ki67, P65, and EGFR in the lesional epithelium can support the diagnosis of PIOSCC.

Long-term results of a randomized phase III trial of TPF induction chemotherapy followed by surgery and radiation in locally advanced oral squamous cell carcinoma.

Previously, we conducted a randomized phase III trial of TPF (docetaxel, cisplatin, and 5-fluorouracil) induction chemotherapy in surgically managed locally advanced oral squamous cell carcinoma (OSCC) and found no improvement in overall survival. This study reports long-term follow-up results from our initial trial. All patients had clinical stage III or IVA locally advanced OSCC. In the experimental group, patients received two cycles of TPF induction chemotherapy (75mg/m2 docetaxel d1, 75mg/m2 cisplatin d1, and 750mg/m2/day 5-fluorouracil d1-5) followed by radical surgery and post-operative radiotherapy; in the control group, patients received upfront radical surgery and post-operative radiotherapy. The primary endpoint was overall survival. Among 256 enrolled patients with a median follow-up of 70 months, estimated 5-year overall survival, disease-free survival, locoregional recurrence-free survival, and distant metastasis-free survival rates were 61.1%, 52.7%, 55.2%, and 60.4%, respectively. There were no significant differences in survival rates between experimental and control groups. However, patients with favorable pathologic responses had improved outcomes compared to those with unfavorable pathologic responses and to those in the control group. Although TPF induction chemotherapy did not improve long-term survival compared to surgery upfront in patients with stage III and IVA OSCC, a favorable pathologic response after induction chemotherapy may be used as a major endpoint and prognosticator in future studies. Furthermore, the negative results observed in this trial may be represent type II error from an underpowered study. Future larger scale phase III trials are warranted to investigate whether a significant benefit exists for TPF induction chemotherapy in surgically managed OSCC.

Randomized phase III trial of induction chemotherapy with docetaxel, cisplatin, and fluorouracil followed by surgery versus up-front surgery in locally advanced resectable oral squamous cell carcinoma.

PURPOSE: To evaluate induction chemotherapy with docetaxel, cisplatin, and fluorouracil (TPF) followed by surgery and postoperative radiotherapy versus up-front surgery and postoperative radiotherapy in patients with locally advanced resectable oral squamous cell carcinoma (OSCC). PATIENTS AND METHODS: A prospective open-label phase III trial was conducted. Eligibility criteria included untreated stage III or IVA locally advanced resectable OSCC. Patients received two cycles of TPF induction chemotherapy (docetaxel 75 mg/m(2) on day 1, cisplatin 75 mg/m(2) on day 1, and fluorouracil 750 mg/m(2) on days 1 to 5) followed by radical surgery and postoperative radiotherapy (54 to 66 Gy) versus up-front radical surgery and postoperative radiotherapy. The primary end point was overall survival (OS). Secondary end points included local control and safety. RESULTS: Of the 256 patients enrolled onto this trial, 222 completed the full treatment protocol. There were no unexpected toxicities, and induction chemotherapy did not increase perioperative morbidity. The clinical response rate to induction chemotherapy was 80.6%. After a median follow-up of 30 months, there was no significant difference in OS (hazard ratio [HR], 0.977; 95% CI, 0.634 to 1.507; P = .918) or disease-free survival (HR, 0.974; 95% CI, 0.654 to 1.45; P = .897) between patients treated with and without TPF induction. Patients in the induction chemotherapy arm with a clinical response or favorable pathologic response (≤ 10% viable tumor cells) had superior OS and locoregional and distant control. CONCLUSION: Our study failed to demonstrate that TPF induction chemotherapy improves survival compared with up-front surgery in patients with resectable stage III or IVA OSCC.

Interval cancers in nasopharyngeal carcinoma screening: comparing two screening intervals after a negative initial screening result.

OBJECTIVES: To examine the optimal screening interval among the individuals who received a negative Epstein-Barr virus immunoglobulin A antibodies against viral capsid antigen (VCA-IgA) serum test result and who comprised the majority of the population screened for nasopharyngeal carcinoma (NPC). METHODS: Screening was performed in Sihui, Guangdong, China, offering a repeated screening for participants with an initial negative test either after 4-5 years in one centre (short interval centre), or 9-10 years in another (long interval centre). The characteristics and incidence rates (IRs) of interval NPCs (defined as cases diagnosed outside the screening protocol while within the screening interval) were compared between these two centres. Standard incidence ratios (SIRs) were also calculated using the general Sihui population as the reference. RESULTS: Seven interval NPCs were detected in the short interval centre (IR: 17.8/10(5) person-years) and 20 in the long interval centre (IR: 20.8/10(5) person-years during the first four years and 43.5/10(5) person-years during the remaining years). The SIR in the short interval centre was 0.43 (95% confidence interval [CI]: 0.17-0.89); SIR in the long interval centre was 0.47 (95% CI: 0.17-1.02) during the first four years and 0.90 (95% CI: 0.49-1.51) during the remaining years. No aggressive interval NPC was observed in the short interval centre; four were identified in the long interval centre. CONCLUSIONS: The incidence of NPC, especially aggressive NPC, was low during the first few years after a negative screening; the incidence increased to the general population level afterwards. A screening interval of 4-5 years may therefore be more suitable than 9-10 years after a negative VCA-IgA test in NPC screening.

Clinical analysis of Castleman disease (hyaline vascular type) in parotid and neck region.

OBJECTIVE: The aim of this study was to analyze a single institution's experience in clinical diagnosis, treatment, and prognosis of Castleman disease (hyaline vascular type) in the parotid and neck region. STUDY DESIGN: From 2004 to 2008, a total of 10 consecutive patients with Castleman disease (hyaline vascular type) in the parotid and neck region underwent surgery were included in this retrospective study. The preoperative examinations, clinical diagnosis, surgical treatment, and prognosis were recorded and analyzed. RESULTS: Of the 10 patients, 4 were males and 6 female; their age ranged from 13 to 54 years with a mean of 26.6 years. The lesion occurred in the parotid region in 3 patients, in the neck region in 5 patients, and in both the parotid and neck regions in 2 patients. Their course of disease ranged from 3 months to 48 months with a mean of 12.5 months; 70% of the patients (7 out of 10) had a course of disease of <12 months. The patients always had no obvious complaint, and the laboratory examinations were almost within the normal limits. Magnetic resonance imaging/angiography were valuable on clinical diagnosis and differential diagnosis. All patients underwent surgical removal of the masses completely. During the follow-up period, which ranged from 9 months to 60 months with a mean of 38.9 months, no recurrence of the lesion occurred, and the quality of life of each patient was good. CONCLUSIONS: Castleman disease (hyaline vascular type) in the parotid and neck region is rare, with clinical manifestation and physical examination the same as benign lesions. There is no specific indication in the laboratory tests and imaging examinations; however, magnetic resonance imaging/angiography has potential value on clinical diagnosis and differential diagnosis. Surgical resection is the choice of treatment with good prognosis.

Intralesional injection of Pingyangmycin for vascular malformations in oral and maxillofacial regions: an evaluation of 297 consecutive patients.

The purpose of the study was to investigate the indications and treatment results of intralesional injection of Pingyangmycin for vascular malformations in oral and maxillofacial regions. Between June 2002 and July 2007, 297 patients with oral and maxillofacial vascular malformations (except venular malformation and arteriovenous malformation) were treated with percutaneous injection of Pingyangmycin in our department. There were 159 males and 138 females aged from 8 months to 72 years (mean age 20.6 years). The types of the disease included 98 lymphatic malformations (66 microcystic and 32 macrocystic malformations), 179 venous malformations, and 20 mixed lymphatic-venular or venous malformations. The lesions were located in the oral and maxillofacial and head and neck regions, and measured 0.8 cm x 1.0 cm -12.4 cm x 10.5 cm in size. Two hundred and forty-nine patients underwent intralesional injection of Pingyangmycin alone, 30 patients had laser therapy, and 18 patients underwent surgical excision as well. The number of injection sessions was 1-5, with an average of 3.5 times. Pingyangmycin, dexamethasone, and lidocaine were mixed for injection at concentrations of 1.0mg of Pingyangmycin per milliliter for microcystic lymphatic malformation and 2.0mg of Pingyangmycin per milliliter for venous malformation and macrocystic lymphatic malformation. The patients were followed up for 1-6 years after treatment. The results were evaluated based on B-type ultrasound examinations before and after treatment. The clinical cure rate of venous malformation, macrocystic lymphatic malformation, microcystic lymphatic malformation and mixed malformation was 74.86%, 84.38%, 38.88%, and 60.0%. Five patients had fever. No ulceration, necrosis, or anaphylactic reaction was found. Intralesional injection of Pingyangmycin at an adequate concentration can be used as the therapy of choice for small and medium-sized venous malformations, macrocystic lymphatic malformations, microcystic lymphatic malformations, and mixed malformations. The advantages included a high cure rate, safety and reliability, short course, easy manipulation, and fewer side effects with satisfactory recovery of appearance and function.

Fibronectin: characterization of a somatic mutation in Sturge-Weber syndrome (SWS).

Sturge-Weber syndrome (SWS) is a rare, congenital neurocutaneous disorder with a leptomeningeal, facial trigeminal nerve dominative area and choroidal angioma. The cause of this disease remains unclear. Due to the occurrence of localized abnormality of blood vessel formation, somatic mutation has been put forward. Studies have indicated that fibronectin gene expressions in the SWS port-wine-derived fibroblasts are increased. Fibronectin is an important extracellular matrix molecule with key roles in regulating angiogenesis and vasculogenesis, in maintenance of the blood-brain barrier, blood vessel structure and function, as well as brain tissue responses to seizures. This is consistent with the presence of a hypothesized somatic mutation underlying SWS. In this study, we have proposed that fibronectin may be reflection of somatic mutation. Further research should be done to study the role of fibronectin in the pathogenesis of SWS. Understanding the pathophysiology of Sturge-Weber syndrome will help us to establish future neuroprotective strategies and novel treatment modalities.

Spontaneous thoracic duct cyst presenting as a left supraclavicular mass - report of a case and review of literature.

Spontaneous and asymptomatic supraclavicular thoracic duct cysts occurring in the neck are the rarest. We report a case of a huge thoracic duct cyst occurring in the supraclavicular fossa with a review of the literature and management options. A 28-year-old female had a left supraclavicular mass with a 10-year history. A cervical thoracic duct cyst was diagnosed after chemical analysis of the milky fluid obtained by preoperative fine-needle aspiration. Treatment was achieved by surgical excision of the cyst and thoracic duct ligation. Pathological analysis of the cyst after excision confirmed the diagnosis. In the case of left supraclavicular masses, the rare differential diagnosis of thoracic duct cysts must be considered as a possibility. Magnetic resonance imaging as the imaging method of choice and chemical analysis of the milky fluid obtained by preoperative fine-needle aspiration are sufficient for primary diagnosis. The treatment of this disease consists of simple excision.

Intralesional injection of Pingyangmycin may be an effective treatment for epulis.

Gingival epulis represents a family of benign tumors and tumorlike masses of the gingiva. A spectrum of inflammatory and other reactive changes can be observed pathologically as granulation, fibrous or vascular tissue. It may occur at any age, but most commonly found in patients at their twenties and sixties. Women are more frequently affected than men. Surgical excision or removal is the treatment of choice, and wider resection including extraction of the involved teeth and adjacent tissues is often required in order to prevent recurrence. However, wider resection may result in cosmetic and functional problems. Epulis bears some similarities with hemangioma both clinically and histopathologically. Therefore, we hypothesize that intralesional injection of Pingyangmycin may be a safe and effective treatment for epulis. The efficacy of this treatment modality is worthy of further investigation.

Occult cervical lymph node metastases in 100 consecutive patients with cN0 tongue cancer.

BACKGROUND: Squamous cell carcinoma (SCC) of the tongue is one of the most common cancers in the oral and maxillofacial region. To provide clinical evidence for selective neck dissection in management of cN0 patients by analyzing the characteristics and correlation of factors of occult cervical lymph node metastases (OCLNM) in patients with SCC of the tongue. METHODS: From 2002 to 2006, 100 consecutive patients with SCC of the tongue were reviewed by analyzing the characteristics of OCLNM, diameter of the tumor, T classifications, depth of invasion, forms of growth, pathological grade and degree of differentiation. RESULTS: The rate of OCLNM in 100 patients with SCC of the tongue was 22%. The most common region with OCLNM was level II in the ipsilateral neck, followed by levels I and III. There were 51.61% (16/31) of OCLNM in level II and 87.10% (27/31) of OCLNM in levels I - III. There was no significant correlation between the diameter of tumor and OCLNM (P > 0.05). OCLNM was statistically significantly correlated with the depth of invasion, forms of growth, pathological grade and degree of differentiation (P < 0.05). The rate of occult metastases increased with the increased pathological grade, the decreased degree of differentiation and the increased depth of invasion. CONCLUSIONS: The most common regions with OCLNM in cN0 patients with SCC of the tongue were levels I - III in the ipsilateral neck. Supraomohyoid neck dissection should be the elective treatment to the neck in patients with cN0 SCC of the tongue by consideration of the clinical and pathological factors for the depth of invasion, forms of growth, pathological grade, and degree of differentiation.

[Current treatment of infantile hemangiomas: an overview of the literature].

Hemangiomas are the most common neoplasm of infancy and childhood, about 40% to 60% of them involve the head and neck region. In recent years, many studies had been carried out on the natural course of hemangiomas, an algorithm for intervention versus observation was proposed, and effective safe treatment plan is devised. Close observation is indictable for hemangiomas which are remaining stable in size or in the involutive phase or post- involutive phase. For large hemangiomas, multiple hemangiomas, life-threatening hemangiomas and problematic hemangiomas with complications such as ulceration, infection, bleeding, dysfunction, etc, systematic drug therapy (Cortico steroids, interferon alpha-2a or 2b ) should be considered. Growing hemangioma can be treated effectively by systematic drug therapy, sclerotherapy, laser therapy or combined therapy. Topical application of imiquimoid and intratumoral injection of steroids or pinyangmycin can be used in selected patients with rapidly growing hemangioma. Surgery is no longer the first choice of treatment for hemangiomas, which is only reserved for correction of large residuals postinvolution.

Use of allogenic acellular dermal matrix in prevention of Frey's syndrome after parotidectomy.

OBJECTIVE: To evaluate the use of an allogenic acellular dermal matrix (ADM) as an interpositional graft to prevent Frey's syndrome after parotidectomy. METHOD: We studied a total of 168 patients with benign parotid gland tumours, including 89 patients with pleomorphic adenoma; 45 with Warthin tumour; 17 with basal cell adenoma; and 17 with miscellaneous tumours. The patients were divided into two groups: the first (control n=104) had superficial or partial parotidectomy alone, and the second (experimental n=64), had superficial or partial parotidectomy with simultaneous placement of an ADM graft. All patients were evaluated for gustatory sweating by clinical examination. For objective assessment, 60 patients (30 from each group) were randomly selected for a starch-iodine test. RESULTS: Subjectively Frey's syndrome was recorded in 63 patients (61%) from the controls and one patient (2%) from the ADM group. Objectively Frey's syndrome was found in 24 patients from the control group (23%) and 2 patients from the ADM group (2%). Salivary fistulas developed in 18 patients from the control group (17%), but in only 1 patient from the ADM group (2%). Both differences were P<0.05, but there was no significant difference between superficial parotidectomy and partial superficial parotidectomy (P=0.714). CONCLUSION: The use of acellular dermal matrix (ADM) as an interpositional graft is an effective way of preventing Frey's syndrome after parotidectomy.