Usefulness of myofascial flap without skin in contemporary oral and maxillofacial reconstruction.

PURPOSE: Pedicle myofascial graft should be considered in contemporary oral and maxillofacial reconstruction for the following reasons: 1) the pedicle myofascial unit is reliable and easily handled; 2) on the grafted myofascia in the oral cavity, the mucosa regenerates naturally with regard to suppleness and surface characteristics; and 3) vascularized myofascial coverage of tissues or materials is useful in some clinical situations. The purpose of this retrospective study was to evaluate the usefulness of this graft material. PATIENTS AND METHODS: Using myofascial flaps from the pectoralis major muscle in 15 patients and from the platysma muscle in 11 patients, several types of reconstructive procedures were conducted in the Department of Oral and Maxillofacial Surgery, Wakayama Medical University. RESULTS: Myofascial tissue was used to cover the surgical defect and for regeneration of oral mucosa (24 patients), to prevent exposure of the mandibular reconstruction plate (4 patients), for prevention of wound breakdown and secondary infection in the oral cavity (2 patients), for vascularized coverage of free grafted autologous bone (2 patients), and for protection of large vessels after radical neck dissection (9 patients). Although partial flap necrosis or wound dehiscence was noticed in 3 patients with a platysma-myofascial graft, the healing process of all patients was favorable and required no additional operations. This procedure is most suitable for the reconstruction of small to medium-sized soft tissue defects in the oral cavity, because it induces the formation of nearly normal mucosa through epithelial regeneration without clear scar formation. CONCLUSIONS: Myofascial flap is a useful option in certain oral and maxillofacial reconstruction cases in which mucosal regeneration and/or vascularized soft tissue coverage are required.

Risk of lingual nerve injuries in removal of mandibular third molars: a retrospective case-control study.

BACKGROUND: Through the analysis of clinical data, we attempted to investigate the etiology and determine the risk of severe iatrogenic lingual nerve injuries in the removal of the mandibular third molar. METHODS: A retrospective chart review was performed for patients who had undergone microsurgical repair of lingual nerve injuries. The following data were collected and analyzed: patient sex, age, nerve injury side, type of impaction (Winter's classification, Pell and Gregory's classification). Ratios for the respective lingual nerve injury group data were compared with the ratios of the respective data for the control group, which consisted of data collected from the literature. The data for the control group included previous patients that encountered various complications during the removal of the mandibular third molar. RESULTS: The lingual nerve injury group consisted of 24 males and 58 females. The rate of female patients with iatrogenic lingual nerve injuries was significantly higher than the control groups. Ages ranged from 15 to 67 years, with a mean age of 36.5 years old. Lingual nerve injury was significantly higher in the patient versus the control groups in age. The lingual nerve injury was on the right side in 46 and on the left side in 36 patients. There was no significant difference for the injury side. The distoangular and horizontal ratios were the highest in our lingual nerve injury group. The distoangular impaction rate in our lingual nerve injury group was significantly higher than the rate for the control groups. CONCLUSION: Distoangular impaction of the mandibular third molar in female patients in their 30s, 40s, and 50s may be a higher risk factor of severe lingual nerve injury in the removal of mandibular third molars.

PD-L1 expression correlated with p53 expression in oral squamous cell carcinoma.

BACKGROUND: Programmed cell death ligand 1 (PD-L1) is an immune checkpoint molecule that attenuates the immune response. PD-L1 contributes to failed antitumor immunity; thereby, blockade of PD-L1 with monoclonal antibody enhances the immune response. Recently, it was reported that PD-L1 was regulated by protein 53 (p53). Besides, cytokeratin 17 (CK17) is thought to be a diagnostic marker of oral squamous cell carcinoma (OSCC). Our aim was to evaluate the correlation between the immunohistochemical expression of PD-L1, p53 and CK17 with clinicopathological characteristics and disease-specific survival in patients with OSCC. METHODS: A total of 48 patients with OSCC were included in this study. Immunohistochemical staining was performed to evaluate the correlation among the expressions of PD-L1, p53 and CK17, and furthermore the correlation among various clinicopathological factors, PD-L1, p53 and CK17. RESULTS: The positive rate of p53, CK17, PD-L1 (tumor cells) and PD-L1 (tumor-infiltrating lymphocytes) was 63.2%, 91.7%, 48.9% and 57.1%. A statistically significant correlation between p53 expression and T stage and TNM stage (p = 0.049, p = 0.03, respectively) was observed. Also, a statistically significant correlation between p53 and PD-L1 (TCs) expression (p = 0.0009) was observed. Five-year disease-specific survival rate was not significantly correlated with gender, TNM stage, p53 expression, PD-L1 expression and CK17 expression. CONCLUSION: The expression of p53 and PD-L1 shows significantly positive correlation in oral squamous cell carcinoma in tumor cells. Also, a significant correlation between p53 expression and T stage and TNM stage was observed. No other significant correlation between PD-L1 staining or CK17 and clinical or pathologic characteristics was identified.

EGFR inhibitor enhances cisplatin sensitivity of oral squamous cell carcinoma cell lines.

Epidermal growth factor receptor (EGFR) is involved in multiple aspects of cancer cell biology. EGFR has already been identified as an important target for cancer therapy, with various kinds of EGFR inhibitors currently used in treatment of several human cancers. Recently, EGFR and its downstream signaling pathways were identified as being associated with cisplatin sensitivity. In addition, EGFR inhibitors have shown significant promise for patients who failed cisplatin-based therapy. In this study, we investigated whether treatment with an EGFR inhibitor improves cisplatin sensitivity in oral squamous cell carcinoma (OSCC) cell lines. The effects of a combination of AG1478, a specific EGFR tyrosine kinase inhibitor, with cisplatin were evaluated in cultured OSCC cell lines and cisplatin-resistant sublines. Higher expression of EGFR and p-EGFR was found in the two cisplatin-resistant cell lines compared with the corresponding parental cell lines. In addition, augmented inhibition of OSCC cell growth by the combination of AG1478 with cisplatin was found in both cell lines. These results suggest that the combination of an EGFR inhibitor and cisplatin may be useful as a rational strategy for the treatment of patients with oral cancer with acquired cisplatin resistance.

Immunohistochemical expression of EGFR and p-EGFR in oral squamous cell carcinomas.

Epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor of the ErbB family, which is expressed or highly expressed in a variety of solid tumors, including oral cancers. High EGFR expression has been correlated with tumor size, metastasis and survival. In recent years, EGFR has been considered a promising target for monoclonal antibody therapy. A total of 52 patients with oral squamous cell carcinoma (OSCC) were selected for EGFR and phosphorylated EGFR (p-EGFR) detection. Immunohistochemical staining was performed to evaluate EGFR and p-EGFR expression. Positive EGFR and p-EGFR staining was present in 92.3% (48/52) and 98.0% (51/52) of all cases, respectively. High EGFR and p-EGFR expression was present in 63.4% (33/52) and 69.2% (36/52) of all cases, respectively. EGFR and p-EGFR expression did not correlate with the clinical factors tumor stage, regional lymph node metastasis, or distant metastasis. However, a statistically significant correlation was identified between high EGFR expression and the pathologic factor tumor invasion. As a conclusion, the majority of OSCCs highly express EGFR and p-EGFR, indicating the importance of studying the efficacy of anticancer therapy targeting these signal factors.

A Case of Verruciform Xanthoma Arising in the Tongue.

Verruciform Xanthoma (VX) is a rare lesion of the oral cavity. Histologically, it is characterized by papillary or verrucous proliferation of squamous epithelium and numerous foam cells. VX arising in the tongue is comparatively rare, as most cases of VX in oral cavity occur in gingiva. A 65-year-old woman was referred to our clinic with a mass on the left side of the tongue. The lesion was yellowish, and its surface was granulated. The patient had neither tenderness nor any symptoms. The lesion was clinically diagnosed to be a benign tumor, and hence, biopsy was performed, according to which it was diagnosed as hyperparakeratosis. Based on this diagnosis, the tumor was excised under general anesthesia. Histopathologically, the tumor consisted of stratified squamous epithelium with parakeratosis and elongated rete ridges. Aggregation of foam cells was observed between and under the rete ridges. From these features, a diagnosis of VX was made. The patient has had no local recurrence as of three years post-operatively.

Downregulation of midkine induces cisplatin resistance in human oral squamous cell carcinoma.

The presence of drug-resistant cancer cells has been associated with poor clinical outcomes. Cisplatin is one of the most effective chemotherapeutic agents commonly used for several malignancies including oral squamous cell carcinoma (OSCC). Although cisplatin resistance is a major obstacle in cancer treatment, mechanisms by which it develops are not well understood. Midkine (MK), a heparin-binding growth factor, has various cancer-related functions. In this study, we investigated whether MK is involved in cisplatin resistance in OSCC. We demonstrated that the Sa-3R cell line, which is OSCC cisplatin-resistant, exhibited lower MK expression with slow growth compared with its parent, Sa-3 cells. In Sa-3 cells, downregulation of MK expression significantly reduced cisplatin sensitivity, cell growth, and the expression of cyclin D1 and cyclin E1. MK knockdown suppressed cellular cisplatin accumulation via induction of ATP-binding cassette efflux transporters. These data suggest that MK may play important roles in cisplatin resistance in OSCC by modulating both cell growth and intracellular cisplatin accumulation.

Expression of ADAMTS-5 in deformed human temporomandibular joint discs.

OBJECTIVE: To study the expression of a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5) in tissue samples of deformed human temporomandibular joint (TMJ) discs and cells obtained from the discs. MATERIALS AND METHODS: Eleven adult human TMJ discs (nine diseased discs and two normal discs) were used in this study. The nine diseased discs were obtained from nine patients with internal derangement (ID) and osteoarthritis (OA) in the TMJ. These patients all had anteriorly displaced discs and deformed mandibular condyles, making conservative therapy impossible. The tissues were immunohistochemically stained using ADAMTS-5 antibodies. In addition, an articular disc cell line from one case was established by collagenase treatment. The subcultured cells under both normal and hypoxic conditions (O2: 2%) were incubated for 3, 6, 12 and 24 h after addition of interleukin-1beta (IL-1beta) (1 ng/mL). Subsequently, the expression of ADAMTS-5 was examined using reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The control group showed negative reactions on immunohistochemical staining. The discs extracted from cases with ID and OA presented positive reactions for ADAMTS-5. The expression of ADAMTS-5 mRNA increased under both normoxia and hypoxia with the addition of IL-1beta, and the peak was observed after 3 h. CONCLUSION: These results suggest that ADAMTS-5 is related to deformation and destruction of human TMJ discs affected by ID and OA.