• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.1
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• pp.53-58
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• 2020

Pretargeting is a two-component strategy often used for tumor targeting to enhance the tumor-to-background ratio in cancer diagnosis as well as therapy. In the multistep strategy, the highly specific unlabeled monoclonal antibodies (mAbs) with the reactive site is allowed to get localized at tumor site first, and then small and fastclearing radiolabeled chelator with counter reactive site is administered which covalently attaches to mAbs via inverse electron demand Diels-Alder reaction (IEDDA). The catalyst-free IEDDA cycloaddition reaction between 1,2,4,5-tetrazines and strained alkene dienophiles aid with properties like selective bioconjugation, swift and high yielding bioorthogonal reactions are emergent in the development of radiopharmaceutical. Due to its fast pharmacokinetics, the in vivo formed radioimmunoconjugates can be imaged at earlier time points by short-lived radionuclides like ¹⁸F and ⁶⁸Ga; it can also reduce radiation damage to the normal cells. Ultimately, this review elucidates the updated status of pretargeting based on antibodies and IEDDA for tumor diagnosis (PET and SPECT) and therapy.

• 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.

• The Korean Journal of Cytopathology
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• v.1 no.1
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• pp.1-17
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• 1990

Hepatocellular carcinoma (HCC) is malignant tumor frequently occurring in Koreans. There have been few reports regarding the cytologic findings of fine needle aspiration (FNA) of HCC. Most have suggested a diagnostic problem in the cytology distinguishing HCC from some benign hepatic lesions-for example, a regeneration nodule in cirrhosis and liver cell adenoma. In spite of its high frequency in Korea, no cytologic study has been reported, concerning the FNA of HCC. In an attempt to achieve cytologic criteria for the diagnosis of HCC, the authors studied retrospectively cytopathologic findings of 247 cases of HCC. These cases were confirmed either by histoiogic examination including lobectomy, biopsy, or ceil block material, or, when tissue diagnosis was unavailable, by a high serum alpha-fetoprotein level (over 400 I. U.). All aspiration smears were stained by the Papanicolaou method. In each case, the smears were analyzed for cell patterns and various cytomorphology of the tumor cells. The smear background was assessed for the presence of tumor cell necrosis and inflammatory components and compared to that of metastatic carcinomas. The cell patterns were classified as trabecular, acinar, dispersed, and irregular. The cytologic parameters analyzed included the degree of nuclear atypia and the presence of mitoses, intranuclear cytoplasmic inclusions, nucleolar prominency, endothelial lining, multinucleated giant cells, eosinophiic globules, bile, and Mallory body. Most of the FNA of HCC showed markedly cellular smears. The tumor cells were most frequently arranged in a trabecular pattern (80.3%). The irregular (12.6%), the acinar (5.5%), and the dispersed patterns (1.7%) followed in decreasing frequency. Individual hepatoma cells were larger than normal liver cells. However, they had morphologic features characteristic of the hepatic cells the cells were round or polygonal, their cytoplasm was abundant and granular with eosinophilic or amphophilic stainability, and their nuclei were round to oval, located centrally, and tended to have prominent nucleoli. Anaplasia and pleomorphism of tumor cells were generally mild to moderate. These findings existed even in very well differentiated cases. Mitotic figures were present in about 85% of the cases. Prominent nucleoli were observed only in about half the cases. The frequency of other cytologic features was as follows intranuclear cytoplasmic inclusion in 86.8% : endothelial lining in 56.1% : bile in 19.8% : and giant cells in 60.1%. Clear cells were often present in 11.7%, Most aspiration smears of HCC displayed clean background without necrosis or inflammatory material in contrast to the dirty, necrotic background of metastatic cancers and cholangiocarcinomas. Based on the above mentioned features, it is suqqested that the cytologic critieria most important for the diagnosis of HCC include a markedly cellular smear, trabecular pattern, hepatocytoid appearance of tumor cells, endothelial lining, the presence of bile, giant cells, intranuclear cytoplasmic inclusions, and prominent nucleoli, Among these, trabecular pattern, endothelial lining, giant cells and clean smear background are points to be considered in differentiating HCC from metastatic and cholangiocellular carcinoma.

• The Korean Journal of Nuclear Medicine
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• v.36 no.1
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• pp.8-18
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• 2002

Early and accurate diagnosis of tumors using positron omission tomography (PET) has been the focus of considerable interest due to its high metastasis and mortality rates at late detection. PET radiopharmaceuticals-which exhibit a high tumor-to-background uptake ratio, and appropriate metabolic characteristics, and pharmacokinetics-are attractive tools for tumor imaging. Tumor imaging by these radiopharmaceuticals are based on metabolic and receptor imaging. The former is based on accelerated metabolism in tumor tissue compared to normal tissue and the rate roughly corresponding to the rate of growth of tumors. Radiopharmaceuticals for this purpose include radiolabeled sugars, amino acids, and nucleosides which detect increased glucose utilization, protein synthesis, and DNA synthesis, respectively. Tumor receptor imaging is based on the proliferation of tumor cells regulated by many hormones and growth factors, which bind to the corresponding receptors and exhibit the biological responses Radiopharmaceuticals used to image the tumor receptor systems may be ligands for the specific receptors and antibodies for the growth factor receptors. Some antitumor agents have been labeled with radionuclides and used to study in vivo biodistribution and pharmacokinetics in humans. This overview describes typical PET radiopharmaceuticals used for tumor imaging based on their uptake mechanisms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.359-366
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• 2016

The normal tissue in radiation therapy, to minimize radiation, it is most important to maximize local tumor control rates in intensive research the exact dose to the tumor sites. Therefore, the initial, therapist accuracy of detecting movement of the patient fatigue therapist has been a problem that is weighted down directly. Also, by using a web camera, a difference value between the image to be updated to the reference image is calculated, if the result exceeds the reference value, using the system for determining the motion has occurred. However, this system, it is not possible to quantitatively analyze the movement of the patient, the background is changed when moving the treatment bed in the co-therapeutic device was not able to sift the patient. In this paper, using a alpah(${\alpha}$) filter index is an attempt to solve these limitations points, quantifies the movement of the patient, by separating a background image of the patient and treatment environment, and movement of the patient during treatment It senses only, it was possible to reduce the problems due to patient movement.

• IMMUNE NETWORK
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• v.5 no.2
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• pp.110-116
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• 2005

Background: As an attempt to develop a strategy to improve the protective immune response to GM-CSF-secreting CT26 (GM-CSF/CT26) tumor vaccine, we have investigated whether the apoptogenic treatment of GM-CSF/CT26 prior to vaccination enhances the induction of anti-tumor immune response in mouse model. Methods: A carcinogeninduced mouse colorectal tumor, CT26 was transfected with GM-CSF gene using a retroviral vector to generate GM-CSF-secreting CT26 (CT26/GM-CSF). The CT26/GM-CSF was treated with ${\gamma}$-irradiation or mitomycin C to induce apoptosis and vaccinated into BALB/c mice. After 7 days, the mice were injected with a lethal dose of challenge live CT26 cells to examine the protective effect of tumor vaccination in vivo. Results: Although both apoptotic and necrotic CT26/GM-CSF vaccines were able to enhance anti-tumor immune response, apoptotic CT26/GM-CSF induced by pretreatment with ${\gamma}$-irradiation (50,000 rads) was the most potent in generating the anti-tumor immunity, and thus 100% of mice vaccinated with the apoptotic cells remained tumor free for more than 60 days after tumor challenge. Conclusion: Apoptogenic pretreatment of GM-CSF-secreting CT26 tumor vaccine by ${\gamma}$-irradiation (50,000 rads) resulted in a significant enhancement in inducing the protective anti-tumor immunity. A rapid induction of apoptosis of CT26/GM-CSF tumor vaccine at the vaccine site might be critical for the enhancement in anti-tumor immune response to tumor vaccine.

• The Korean Journal of Cytopathology
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• v.4 no.2
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• pp.150-155
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• 1993

We report a case of placental site trophoblastic tumor with cytologic features of cervico-vaginal smear. The smear revealed several loose clusters of atypicai cells in slightly hemorrhagic and inflammatory background. Tumor cells were large in size and polyhedral to round with abundant cytoplasm Nuclei revealed consider-able variation in size, shape, and degree of chromatin clumping. Cytologically, it was difficult to differentiate from squamous cell carcinoma of uterine cervix. Curettage and hysterectomy specimen revealed typical histologic features of placental site trophoblastic tumor composed of intermediate type trophoblasts.

• The Korean Journal of Cytopathology
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• v.4 no.2
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• pp.160-165
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• 1993

Phyllodes tumor of the breast, especially malignant, is a rare tumor which has characteristic cytologic features. We recently experienced a case of fine needle aspiration cytology of malignant phyllodes tumor of the breast metastatic to the lung. The aspirate showed cellular smear with biphasic population of epithelial and stromal cells. Many individual large cells with round hyperchromatic nuclei were found in the necrotic background and stromal cell atypia was also present. Chondrosarcomatous fragments were also seen in cytologic specimens.

• The Korean Journal of Cytopathology
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• v.19 no.1
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• pp.47-51
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• 2008

Adenomatoid tumor is a benign neoplasm of a mesothelial origin, and it usually occurs in the reproductive organs, especially in the epididymis. The author experienced a case of adenomatoid tumor involving the tunica albuginea and testicular parenchyme without any evidence of epididymis involvement. The patient was a 36-year-old man with a painless scrotal mass that he had experienced for 2 months, and this mimicked testicular neoplasia, including metastatic carcinoma, or other benign lesions. The imprint cytology of the tumor showed a hypocellular smear with mainly arranged cells in cohesive monolayered clusters along with occasional singly dispersed cells and naked nuclei in a clean background. The cellular clusters formed vague glandular and cord-like structures. The tumor cells were large polygonal to columnar cells with a relatively monomorphic appearance. The nuclei were oval to round shape and they showed vesicular, fine chromatin and inconspicuous nucleoli. The cytoplasm was moderate to abundant, and it contained fine vacuoles in some tumor cells. Mitoses and cellular pleomorphism were not present. Awareness of the cytologic finding of this lesion is necessary to screen or differentiate a testicular or paratesticular mass before and/or during surgery because the cytology may be useful as a diagnostic tool. Pathologists should be aware of the cytologic features of common lesions in this anatomic region so as to avoid performing aggressive and unnecessary surgical procedures.

• Archives of Craniofacial Surgery
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• v.16 no.1
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• pp.17-23
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• 2015

Background: Treatment of skull base tumors is challenging due to limited access and presence of important neurovascular structures nearby. The success of a complete tumor resection depends on the extent of tumor exposure and secure field of view. While these tumors are often removed by transcranial endoscopic access, transfacial approach is sometimes required depending on the location and size of the tumor. This study describes various transfacial approaches in patients undergoing skull base tumor resection. Methods: From March to November 2013, 15 patients underwent skull base tumor resection via transfacial accesses at a tertiary institution. Data were reviewed for patient demographics, type of access used, completeness of tumor resection, surgical outcome, and postoperative complications. Results: Two clivus tumor patients underwent transmaxillary approach; three tuberculum-sellae and suprasellar-hypothalamus tumor patients underwent transbasal approach; three clinoid and retrobulbar intraconal orbital tumor patients underwent orbitozygomatic approach; and seven petroclival-area, pons, cavernous sinus, and lateral-sphenoid-wing tumor patients underwent zygomatic approach. In all cases, the upper and lower margins of the tumor were visible. Complete tumor removal consisted of 10 cases, and partial tumor removal in 5. There were no immediate major complications observed for the transfacial portion of the operations. The overall cosmetic results were satisfactory. Conclusion: Plastic surgeons can use various transfacial approaches according to the location and size of skull base tumors to secure a sufficient field of view for neurosurgeons.