Immunohistochemical study on expression of MMP-2 and MMP-9 in irritation fibroma, oral leukoplakia and oral squamous cell carcinoma

MMP-2 and MMP-9, type IV collagenases which degrade basement membrane, have been known to play important roles in invasion and metastasis of tumor cells, In addition, they seem to be involved in cell differentiation, apoptosis, angiogenesis and immunity, etc. We immunohistochemically examined epithelial and stromal expressions of MMP-2 and MMP-9 in irritation fibroma, oral leukoplakia, and oral squamous cell carcinoma (OSCC) and have some results as follows: 1. Irritation fibromas, oral leukoplakias and OSCCs mostly showed increased expression of MMP-2 and MMP-9 in the epithelium and connective tissue compared with normal mucosa. 2. There was a significant difference in the epithelial expression of MMP-2 and MMP-9 between irritation fibroma and oral leukoplakia. 3. There was a significant difference in the epithelial and stromal expression of MMP-2 and MMP-9 between irritation fibroma and OSCC. 4. There was a significant difference in the stromal expression of MMP-9 between oral leukoplakia and OSCC. We concluded that rritation fibroma, oral leukoplakia and OSCC have somewhat different characteristics of MMP-2 and MMP-9 expressions, which perhaps result from different pathogenesis.

The effects of irradiation and hyperbaric oxygen therapy on microvascular anastomosis

Malignant tumors of the head and neck frequently require treatment with both radiotherapy and surgery. Reconstruction of the defect in previously irradiated field is a challenge to surgeon, who must produce both a functional and an esthetic result. Hyperbaric oxygen therapy(HBO) has been used in an attempt to reduce the deleterious effects of radiation. But the issue of whether prior irradiation and HBO of the recipient site of a free flap affects the result of reconstruction continues to generate controversy. So, the effects of irradiation and hypergbaric oxygen therapy on microvascular anastomosis was evaluated in an experimental study in femoral vessels of rats. The experimental groups were divided into 3 groups, contorol group, irradiation group, and irradiation and HBO group. Preoperative irradiation was delivered in the left groin field with single dose corresponding 2,000cGy and total 48 hours of HBO was given 100% oxygen at 2.4 atmosphere for 4 weeks. The femoral vessels of 60 rats were anastomosed after irradiation and HBO treatment. Three days, 1 week, 2 weeks and 4 weeks after surgery, the femoral vessels were evaluated for patency and histopathologic changes. There was no notable effect of irradiation on patency of femoral vessels in rats and the radiation effects were obvious on histological examination which showed the sloughing of the endothelial cells, subintimal hyperplasia and fibrosis on the media and adventitia of femoral arteries. The histologic changes of the femoral veins were mild and not typical. But the effects of hyperbaric oxygen therapy after irradiation was seen not marked difference in irradiation group.

A Clinical Study of Malignant Tumors of the Maxilla

Malignant tumors of the maxilla represent about 3-4% of head and neck malignant neoplasm and the origins are maxillary gingiva, hard palate and maxillary sinus. We are to investigate clinical features and results according to various treatment modalities of maxillary malignant tumor to get information for better treatment results. Sixty patients with malignant maxillary tumors treated at Yonsei medical center from 1992 to 1997 were studied retrospectively. They are evaluated according to clinical signs & symptoms, stages at first diagnosis, primary site, histopathologic features, treatment method, recurrence and survival rate with clinical records, biopsy results and CT radiograph. The most common primary site was maxillary sinus and most common histopathology was squamous cell carcinoma. The local recurrence rate was 18% at 5 years, neck failure was 3% and distant metastasis was 18%. Overall survival rate was 78% at 2 years and 69% at 5 years. Failure at primary site is the main problem in the curative treatment. So, to improve survival in these patients efforts should be directed toward improvement of local control.

Mandibulotomy, A Surgical approach for Oral cancer: Its Complications and contributing factors

We reviewed 56 patients who received mandibulotomy at Yonsei medical center between 1989 and 1999. We also analysed the complications associated with mandibulotomy and its contributing factors. The complications occur in 16 patients(28.6%) and are classified into two categories; intraoperative and postperative complications. Nonunion was observed in 5 patients and osteoradionecrosis in 5. The patients who received preoperative radiation therapy were more tend to develop nonunion and osteoradionecrosis. This study suggests the benefits of mandibulotomy as a surgical approach to oral cancer: 1. Paramedian osteotomy was recommended for preservation of neurovascular bundle and ease of surgical access. 2. By using thin saw blade, reapproximation was improved with minimal bone loss. 3. osteotomy on anterior mandible which lies outside the usual portals of radiation therapy decreases the incidence of osteoradionecrosis.