• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.4
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• pp.315-320
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• 2021

Carbon-ion radiotherapy (CIRT) is on the rise as a treatment choice for malignant tumor. Compared to conventional radiotherapy, particle beams have different physical and biological properties. Particle beam provides a low entry dose, deposits most of the energy at the endpoint of the flight path, and forms an asymptotic dose peak (the "Bragg peak"). Compared to protons, carbon with its larger mass decreases beam scattering, resulting in a sharper dose distribution border. We report a 50-year-old male who underwent CIRT without surgical resection on osteosarcoma of the mandible. After CIRT, the patient's pain was gone, and the malignant mass remained stable with accompanying necrosis. Nine months later, however, magnetic resonance imaging demonstrated progression of the left mandibular osteosarcoma with pulmonary metastases. After multidisciplinary discussion, concurrent chemoradiotherapy was conducted. While necrotic bone segments came out of the mandible during subsequent periodic outpatient visits, the tumor itself was stable. Thirty months after his first visit and diagnosis, the patient is waiting for chemotherapy. Although CIRT is superior in treating radioresistant hypoxic disease, CIRT is in its infancy, so care must be taken for its indications and complications.

• Radiation Oncology Journal
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• v.33 no.4
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• pp.265-275
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• 2015

Despite the increasing use of stereotactic body radiation therapy (SBRT) and stereotactic radiation surgery (SRS) in recent years, the biological base of these high-dose hypo-fractionated radiotherapy modalities has been elusive. Given that most human tumors contain radioresistant hypoxic tumor cells, the radiobiological principles for the conventional multiple-fractionated radiotherapy cannot account for the high efficacy of SBRT and SRS. Recent emerging evidence strongly indicates that SBRT and SRS not only directly kill tumor cells, but also destroy the tumor vascular beds, thereby deteriorating intratumor microenvironment leading to indirect tumor cell death. Furthermore, indications are that the massive release of tumor antigens from the tumor cells directly and indirectly killed by SBRT and SRS stimulate anti-tumor immunity, thereby suppressing recurrence and metastatic tumor growth. The reoxygenation, repair, repopulation, and redistribution, which are important components in the response of tumors to conventional fractionated radiotherapy, play relatively little role in SBRT and SRS. The linear-quadratic model, which accounts for only direct cell death has been suggested to overestimate the cell death by high dose per fraction irradiation. However, the model may in some clinical cases incidentally do not overestimate total cell death because high-dose irradiation causes additional cell death through indirect mechanisms. For the improvement of the efficacy of SBRT and SRS, further investigation is warranted to gain detailed insights into the mechanisms underlying the SBRT and SRS.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.3
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• pp.301-304
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• 2000

Hemangiopericytoma is uncommon vascular neoplasm that arises from pericytes arround the capillary walls. It was first described as a distinct vascular neoplasm by Stout and Murray in 1942 The anatomic distribution is widespread throughout the body, with approximately one third occur in the head and neck. No sex predilection has been found. Although middle age appears to be the most prevalent time of onset, this neoplasm has been found in all age groups. The differentiation between benign and malignant hemangiopericytoma can be difficult. Although the majority of these tumors are benign, there are malignant variants that can metastasize. Metastasis of seemingly benign tumors may appear year of decade later, so long term close follow-up is needed. The treatment of choice is complete surgical excision of the tumor. Despite their vascular origin, these tumors are relatively radioresistant. Radiation therapy is reserved for inoperable metastases or treatment of postoperative surgical fields. Here we present a case of hemangiopericytoma occuring on the Lt. buccal mucosa.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3015-3023
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• 2012

The mitochondrial antioxidant protein manganese superoxide dismutase (MnSOD) may represent a new type of tumor suppressor protein. Overexpression of the cDNA of this gene by plasmid or recombinant lentiviral transfection in various types of cancer leads to growth suppression both in vitro and in vivo. We previously determined that changes in MnSOD expression had bidirectional effects on adriamycin (ADR) when combined with nitric oxide (NO). Radiation induces free radicals in a manner similar to ADR, so we speculated that MnSOD combined with NO would also have a bidirectional effect on cellular radiosensitivity. To examine this hypothesis, TE-1 human esophageal squamous carcinoma cells were stably transfected using lipofectamine with a pLenti6-DEST plasmid containing human MnSOD cDNA at moderate to high overexpression levels or with no MnSOD insert. Blastidicin-resistant colonies were isolated, grown, and maintained in culture. We found that moderate overexpression of MnSOD decreased growth rates, plating efficiency, and increased apoptosis. However, high overexpression increased growth rates, plating efficiency, and decreased apoptosis. When combined with NO, moderate overexpression of MnSOD increased the radiosensitivity of esophageal cancer cells, whereas high MnSOD overexpression had the opposite effect. This finding suggests a potential new method to kill certain radioresistant tumors and to provide radioresistance to normal cells.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3519-3524
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• 2014

Background: Esophageal squamous cell carcinoma (ESCC) is a common cancer with poor prognosis. It has been hypothesized that Oct4 positive radioresistant stem cells may be responsible for tumor recurrence. Hence, we evaluated Oct4 expression in ESCC in pre-treatment, post neo-adjuvant residual and post-surgical recurrent tumours. Materials and Methods: Endoscopic mucosal biopsies were used to study Oct4 expression and the observations were correlated with histological tumor grades, patient data and clinical background. Results: All patients presented with dysphagia with male predominance and a wide age range. Majority of the patients had intake of mixed diet, history of alcohol and tobacco intake was documented in less than half of the patients. Oct 4 expression was significantly higher in poorly differentiated (PDSCC) and basaloid (BSCC) subtypes than the other better differentiated tumor morphology. Oct4 was also expressed by adjoining esophageal mucosa showing low grade dysplasia and basal cell hyperplasia (BCH). Biopsies in PDSCC and BSCC groups were more likely to show a positive band for Oct4 by polymerase chain reaction (PCR). Dysplasia and BCH mucosa also showed Oct4 positivity by PCR. All mucosal biopsies with normal morphology were negative for Oct4. Number of tissue samples showing Oct4 positivity by PCR was higher than that by the conventional immunohistochemistry (p>0.05). Oct4 expression pattern correlated only with tumor grading, not with other parameters including the clinical background or patient data. Conclusions: Our observations highlighted a possible role of Oct4 in identifying putative cancer stem cells in ESCC pathobiology and response to treatment. The implications are either in vivo existence of Oct4 positive putative cancer stem cells in ESCC or acquisition of cancer stem cell properties by tumor cells as a response to treatment given, resulting ultimately an uncontrolled cell proliferation and treatment failure.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.2
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• pp.81-86
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• 1989

Tumors originated from peripheral nerve tissues are neurofibroma, neurilemoma, plexiform neurofibroma, malignant schwannoma, and granular cell tumor. Neurofibromas seem to occur in two forms : The first one is circumscribed solitary neurofibroma and the second group is neurofibromatosis or Von Recklinghausen's disease, which is a congenital and familial disease, presenting abnormalities of the skin, nerve system, bones and soft tissue. A solitary neurofibroma is a benign, relatively circumscribed, noncapsulated tumor which often presents in the skin and subcutaneous tissue as a soft sessile or pedunculated mass. It may occur anywhere in the head and neck, but the common site of the occurrence is the tongue, buccal mucosa, palate in frequency. Since solitary neurofibroma is a relatively radioresistant and its recurrence rate seem to be low, the treatment of choice is surgical excision. The author would like to present a case of unusually large solitary neurofibroma occured in the chin, which was successfully treated with surgical excision and reconstructed using deltopectoral flap and tongue flap.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.1
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• pp.49-66
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• 1993

The purpose of this study was to investigate the early effects of irradiation on the temporomandibular joint in rats. Male rats were singly irradiated with the dose of 5 Gy or 10 Gy to their head and neck region by /sup 60/Co X ray. Experimental animals were sacrificed at each of the following time intervals -1, 2, 3, 5, 7 and 14 days. The specimens were examined with a light microscope, and treated with H & E staining and immuno-histochemical staining. The results were as follows, 1. By light microscopic findings, proliferative and hypertrophic zone were narrowed and hematopoietic cells were few in number at 5 days after irradiation. Repair signs were seen at 7 days after irradiation when decrease in osteoclast, increase in hematopoietic cells and increase of proliferative zone were noted. The 10 Gy irradiated group showed more severe histopathologic change than the 5 Gy group, and their repair was more slow. 2. In the S -100 antibody, positive cells were examined in the glenoid fossa. Positive cells of irradiated group showed more slight decrease in number than the control group. Low radiosensitivity and slow repair was noted in the glenoid foosa. 3. The interarticular disc was high radioresistant, and any histopathologic changes were not seen in disc. 4. Repair was examined clearly with the response to the antibodies. Especially by 5 days after irradiation 5 Gy group showed S-l00 positive cells in hypertrophic zone next to proliferative zone, chondroitin-4-sulfate positive cell in erosive zone next to hypertrophic zone, type-1 collagen positive cell in subchondral bone.

• Korean Journal of Head & Neck Oncology
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• v.3 no.1
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• pp.97-105
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• 1987

Chondrosarcoma of the head and neck is very rare tumor and this incidence was reported to be about 10% of all chondrosarcomas. Maxilla is the most common site of involvement and mandible, paransal sinus, nasal cavity and base of skull in that order. In general, chondrosarcoma has been known to be radioresistant, however since the Princess Margaret Hospital reported that it was radioresponsive tumor in 1980, the role of radiotherapy has been emphasized in terms of local control, especially in head and neck regions where complete excion is often difficult to achieve. The authors experienced 4 cases of chondrosarcoma of head and neck among all 29 chondrosarcoma patients from 1971 to 1985. The clinical and pathologic feature of this disease, it's treatment and prognosis were reviewed along with the literatures.

• Korean Journal of Head & Neck Oncology
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• v.15 no.1
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• pp.29-34
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• 1999

Objectives: This study was carried out to analyze the clinical profile and the results of treatment of a series of patients with extramedullary plasmacytoma(EMP) of the head and neck. Materials and Methods: The clinical features, treatment and survival of 14 patients with EMP seen at Yonsei Medical Center between 1970 and 1998 were carefully reviewed. Results: The median age was 48 years(range 15-75) and there was a male predominance(M:F 1.8:1). Nasal cavities and paranasal sinuses account for 50% of the primary sites and the most common symptom was airway obstruction(50%). Five patients(36%) showed evidence of adjacent bone destruction, one patient had lymph node involvement and one patient had an IgG monoclonal gammopathy at the time of diagnosis. All 5 patients treated with radiotherapy alone achieved local control. Of 5 patients treated with surgery alone, 2 patients(40%) had local failure. Of 3 patient treated with a combination of surgery and radiotherapy, one patient had local recurrence. A total of7 patients(54%) had local, distant or nodal relapses after primary treatment. Six of them received salvage treatment. With salvage treatment of surgery and/or radiotherapy, local control was achieved in 4 of 6 patients. Conversion to multiple myeloma was seen in one patient. Conclusion: Radiotherapy should be recommanded as treatment of choice for EMP of the head and neck. Surgery should be reserved for radioresistant or recurrent tumors, but tumors that are localized and can be removed relatively easily with little morbidity may be treated by primary surgery.

• Journal of Radiation Protection and Research
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• v.30 no.4
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• pp.197-208
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• 2005

Although little information is available on the underlying mechanisms, various genetic factors have been associated with tissue-specific responses to radiation. In the present study, we explored the possibility whether organ specific gene expression is associated with radiosensitivity using samples from brain, lung and spleen. We examined intrinsic expression pattern of 23 genes in the organs by semi-quantitative RT-PCR method using both male and female C57BL/6 mice. Expression of p53 and p21, well known factors for governing sensitivity to radiation or chemotherapeutic agents, was not different among the organ types. Both higher expression of sialyltransferase, delta7-sterol reductase, leptin receptor splice variant form 12.1, and Cu/Zn superoxide dismutase (SOD) and lower expression of alphaB crystalline were specific for spleen tissue. Expression level of glutathione peroxidase and APO-1 cell surface antigen gene in lung tissue was high, while that of Na, K-ATPase alpha-subunit, Cu/ZnSOD, and cyclin G was low. Brain, radioresistant organ, showed higher expressions of Na, K-ATPase-subunit, cyclin G, and nucleolar protein hNop56 and lower expression of delta7-sterol reductase. The result revealed a potential correlation between gene expression patterns and organ sensitivity, and Identified genes which might be responsible for organ sensitivity.