Interleukin-1 beta in unstimulated whole saliva is a potential biomarker for oral squamous cell carcinoma

The objective of this study was to evaluate cytokines in unstimulated whole saliva (UWS) of oral squamous cell carcinoma (OSCC) patients as compared to those with pre- and post-operation for evaluation as markers of OSCC. Sixteen OSCC patients were included in this study. Cytokine concentrations in resting saliva were measured using a Bio-Plex suspension array system. Only interleukin-1 (IL-1) beta showed significantly different cytokine concentration in saliva between pre- and post-operation. IL-1 beta was released from cultured OSCC cells confirmed by ELISA and immunohistochemistry. From this study, IL-1 beta in UWS may be useful for detection of early stage OSCC. More studies are needed to accept the utility of IL-1 beta in UWS for predicting, diagnosis and evaluation of OSCC.

Medical emergency education using a robot patient in a dental setting

INTRODUCTION

In an ageing society, the frequency of medical emergencies in a dental setting appears to be increasing because of a growing number of medically compromised patients. However, we currently have no dental-specific simulation environment with advanced reproducibility for medical emergencies. Therefore, we used the robot patient in objective structured clinical examinations (OSCEs) for testing student competence in emergency management. This study aimed to evaluate student responses to medical emergencies in the dental setting.

MATERIAL AND METHODS

We used 98 fifth-grade dental students at Showa University as subjects and implemented the OSCE task entitled 'Management of medical emergency using a robot patient'. Candidates were asked to manage an emergency situation immediately after local anaesthesia, with one robot patient configured to develop vasovagal syncope and the other to experience adrenaline hypersensitivity. A questionnaire on the educational value of the robot patient was completed after the examination.

RESULTS

Thirty-two per cent of students could not accurately count her pulse because of an inappropriate method. Moreover, 78% could not correctly attach either the tonometer or pulse oximetry to the patient. Accurate diagnoses were given by only 22% of students, with vasovagal syncope diagnosed by 33% and adrenaline hypersensitivity by 8%. From a questionnaire, 78% of students recognised the usefulness of the robot patient in medical emergency training.

CONCLUSION

We found that student responses to the emergency situation were poor. The robot patient is useful in dental education for medical emergency training and assessment not only for situation management but also for differential diagnosis.

The usefulness of intraoral ultrasonography in the evaluation of oral cancer

Many studies focused on the tumour thickness in oral squamous cell carcinomas, suggesting a relationship with the occurrence of cervical metastasis. Accurate preoperative assessment of the tumour thickness of oral cancer would provide useful information for targeting those patients who need elective treatment of the neck. Some useful diagnostic aids to evaluate oral cancer are computed tomography (CT), magnetic resonance imaging (MRI), and intraoral ultrasonography. The purpose of the present study is to compare intraoral ultrasonography with CT and MRI in delineating the disease extent and in measuring the tumour thickness of oral carcinoma. Thirty-nine patients with oral cancer were preoperatively evaluated with intraoral ultrasonography, and CT, and in 26 of them MRI was carried out. High-quality ultrasonographic images were obtained and the tumour thickness was measured within 1 mm. However, in most tumours less than 5.0 mm in thickness, CT and MRI could not detect a sufficient density difference from the normal tissue to accurately delineate the extent of the tumour. There was a significant correlation between measurements by intraoral ultrasonography and the histological sections. The present study shows that ultrasonography is superior to CT and MRI in assessment of the primary lesion of oral carcinoma.

The influence of blood arterial oxygen condition on the tumor response to preoperative radiation therapy in oral cancer patients

The relationship between clinicopathological factors and response of radiation therapy in oral squamous cell carcinoma has been studied. It has been suggested that factors such as tumor site, extent and tumor differentiation determine the response to radiation therapy. It is known that oxygenation is related to the therapeutic effects of radiation therapy. However, there are few reports on the relationship between oxygen condition and the response to radiation therapy. The present study was carried out to assess whether any clinicopathological factors, including an evaluation of the oxygen condition can be used to predict the effects of preoperative radiation therapy in oral squamous cell carcinomas. Forty-seven patients with oral cancer treated with external radiation therapy preoperatively were evaluated. There were no significant differences in response to the radiation with respect to age, sex, tumor site, stage, macroscopic shape of tumors, and the histological factors. The hemoglobin (Hb) and arterial oxygen content (CaO(2)) levels of favorable cases (Hb: 14.4 g/dl, CaO(2) 19.1 ml/dl) were significantly higher than those of unfavorable cases (Hb: 11.0 g/dl, CaO(2): 16.1 ml/dl). These findings suggest that oxygen conditions of oral cancer patients predict tumor response to preoperative radiation therapy.

Apoptosis and p53 are associated with effect of preoperative radiation in oral squamous cell carcinomas

This study was carried out to elucidate whether apoptosis and p53 can be used to stratify oral cancer patients into groups with a favorable or unfavorable response to preoperative radiation therapy. Thirty-two patients were evaluated. The apoptosis index was 1.7+/-0. 9% in the ineffective cases, and it was significantly lower than effective cases (3.2+/-1.2%). While 14 of 16 effective cases (86.7%) did not express p53, 13 of 16 ineffective cases (81.3%) overexpressed p53. These results suggest that mutated p53 in tumors is associated with a poor response to radiation which may be related to evasion of apoptosis in oral cancer.

Infrequent alternations of RB pathway (Rb-p16INK4A-cyclinD1) in adenoid cystic carcinoma of salivary glands

Retinoblastoma (Rb) tumor suppressor genes' products and of the proteins regulating its phosphorylation and function in G1 arrest, p16INK4A and cyclin D1, play important roles in the regulation of the cell cycle. Rb gene inactivation, reflected by the absence of Rb protein expression, has been reported in oral squamous cell carcinomas. p16INK4A is frequently deleted, methylated, or mutated, and cyclin D1 gene amplification in many malignancies including oral squamous cell carcinomas (SCC). These findings suggested that Rb pathway of G1 arrest are the most commonly affected genes in Oral SCC. However, alternation of Rb pathway in salivary gland tumors was not clear. In this study, the expressions of Rb, p16INK4A, and cyclin D1 alternations were analyzed by immunohistochemical assay in 5 specimens of normal salivary glands and twenty-two cases of adenoid cystic carcinomas (ACC). Proliferating cell nuclear antigen (PCNA) labelling index (P.I.) was used for the evaluation of cell proliferation. Rb was consistently expressed in normal salivary glands and ACC. Loss of p16INK4A expression was observed in three cases (13.6%) of ACC. And overexpression of cyclin D1 was observed in four cases (18.2%). The three p16INK4A absent cases were the tumors with predominantly solid pattern and those cases were overexpressed cyclin D1. The cell proliferation activities of p16INK4A absent tumors (P.I. = 24.2 +/- 2.1%) were significantly higher than those of p16INK4A present tumors (P.I. = 10.4 +/- 3.5%) (P < 0.05). Cyclin D1 expression was also related to cell proliferation (P.I. of cyclin D1 negative cases vs. cyclin D1 positive: 10.1 +/- 3.0% vs. 22.6 +/- 3.4%) (P < 0.05). These findings suggested, however, alternations of Rb pathway were infrequent events in ACC of salivary glands and inactivation of p16INK4A, cyclin D1 overexpression may be related to the high cell proliferating activity of ACC.

p53 and MDM2 expression in oral squamous cell carcinoma

The p53 tumor suppressor gene is the most commonly mutated gene in human cancer and is a frequent abnormality in oral squamous cell carcinoma and its precancerous lesions. MDM2 (murine double minute-2), a new proto-oncogene, may be associated with p53 gene products and may negatively affect the transcriptional activating function of p53. The purpose of this study was to investigate the incidence of MDM2 and its relationship to the expression of p53 in oral squamous cell carcinoma and precancerous lesions. Overexpression of p53 and MDM2 proteins was detected in 52 and 40% of oral squamous cell carcinomas, respectively. p53 gene mutation, absent in normal oral epithelium was observed in 31% of the carcinoma cases. Our finding suggested that MDM2 protein may be an alternative mechanism causing p53 protein dysfunction in oral squamous cell carcinoma.

Sequential expression of myc-, ras-, oncogene products and EGF receptor during DMBA-induced tongue carcinogenesis

The mechanism leading to development of oral cancer has not been completely understood. It is currently believed that alternation of a number of genes can result in the development of epidermoid carcinomas. In this investigation, we used a 9,10-dimethyl 1,2-benzanthracene (DMBA)-induced carcinogenesis in a hamster tongue model to investigate the expression of c-myc, c-Ha-ms proteins and epidermal growth factor receptor (EGFr). During the DMBA-carcinogenesis of the tongue, the number of c-myc protein positive cells were increased in epithelial dysplasia and elevated throughout the process of tumorigenesis. The expression of c-Ha-ras protein was detected in normal epithelium. The level of c-Ha-ras protein expression was decreased in the dysplastic stage, and it was almost negative in squamous cell carcinomas. Detection of EGFr overexpression occurred only after 1-4 weeks of DMBA treatment, at a very early stage of tumor development, and increased through carcinogenesis varying individually within the malignant tissues. These results suggest that c-myc protein and c-Ha-ras protein expression may have an important role in malignant transformation, and the overexpression of EGFr can be correlated to very early stages of tumor development in the DMBA-induced in vivo tongue carcinogenesis.

Expression of c-erbB family gene products in adenoid cystic carcinoma of salivary glands: an immunohistochemical study

The tyrosine kinase receptor family, including the epidermal growth factor receptor (EGF-R), c-erbB2 and, more recently, the c-erbB3, has been recognized as being of particular importance in many human malignancies. This study was undertaken to define the role of c-erb B2 and c-erbB3 in adenoid cystic carcinomas (A.C.C.) of the salivary glands. Sixteen cases of A.C.C. were studied immunohistochemically, using antibodies against each erbB gene family product. EGF-R was not detected in any of these samples but c-erbB2 and c-erbB3 gene products (ERBB2and ERBB3) were demonstrated in all A.C.C. sections with some degree of straining. Tubular and cribriform patterns overexpressed particularly large amounts of ERBB2 and ERBB3. Strong staining was mainly demonstrated in tumor cells of the invasive area. These results suggested that overexpression of ERBB2 and ERBB3 is related to tumor differentiation and invasion in adenoid cystic carcinomas.

Prognostic significance of ERBB3 overexpression in oral squamous cell carcinoma

Immunohistochemical analysis of erbB3, as the third member of epidermal growth factor receptor gene family, was performed on 41 cases of oral squamous cell carcinoma, correlating the staining pattern with clinical outcome. High expression of erbB3 protein (ERBB3) was significantly associated with lymph node metastasis (P < 0.05), survival rate (P < 0.05) and mode of invasion (P < 0.01) in this series. These results demonstrated that ERBB3 expression may be helpful in identifying those oral squamous cell carcinomas with higher malignant potential.

Cell proliferation and tumor angiogenesis in oral squamous cell carcinoma

Cell proliferation and vascularization play an important role in the metabolic functions of normal and malignant tissues. Tumor cell proliferation and density of microvessels (DM) in 33 specimens of oral squamous cell carcinoma (SCC) were assessed by immunohistochemical staining of proliferating nuclear cell antigen (PCNA) and JC/70A, respectively. Their staining patterns were compared to the clinicopathologic findings. The PCNA labeling index (LI) showed significantly higher values in advanced carcinomas (T3 and T4) (mean, 20.19 +/- 12.79) than in early carcinomas (T1 and T2) (mean, 9.58 +/- 4.01; P < 0.01). The DM (mean, 105.92 +/- 22.65) and PCNA LI (mean, 25.69 +/- 13.32) of tumors with lymph node metastasis were significantly higher than in tumors without nodal involvement (DM, mean, 72.6 +/- 24.30; P < 0.01) (PCNA LI, mean, 10.25 +/- 3.99; P < 0.001). Marginal DM values were significantly correlated and directly proportional to the mode of tumor invasion. Evaluation of PCNA and DM at the periphery of the tumor may help to identify oral SCC that have higher malignant potential.

Overexpression of p53 is an early event in the tumorigenesis of oral squamous cell carcinomas

The purpose of this study was to determine the timing of p53 overexpression during the development of oral squamous cell carcinomas. Immunohistochemical analysis of p53 expression was performed on 107 cases of oral squamous cell carcinoma, 37 cases of leukoplakia, and 10 cases of cancer-free patient's normal oral mucosa samples. 43 of the 107 (40.2%) oral squamous cell carcinomas showed p53 overexpression. There was no relationship between p53-overexpression and clinicopathological factors, such as size of tumors, lymph node metastasis, hostological differentiation and prognosis. Overexpression of p53 was not detected in 10 normal mucosa. Seven out of 37 (18.7%) samples of leukoplakia and 15 out of 43 (34.8%) samples of noncancerous epithelium adjacent to the p53-positive carcinomas showed p53 overexpression, the results demonstrate that p53 protein may have an important role in the early stages of oral tumorigenesis.