Frequent screening for thyroid cancer has been suggested as a probable explanation for the observed high risk of thyroid cancer in nuclear power plant (NPP) areas. We aimed to compare thyroid cancer screening rates of residents living near NPPs to those of the general population. This study utilized data from two national survey-based studies in 2016 and in 2014, respectively, for residents (n = 1,200) living in administrative districts within 5 km of NPP sites as the interest group, and the general population (n = 228,712) including distantliving residents (n = 19,100) in administrative districts within 30 km of NPP sites as reference groups. We observed an increase in screening rates in residents near NPPs, which may lead to a higher possibility of thyroid cancer detection. Therefore, further epidemiological studies investigating radiation-induced thyroid cancer risk among residents near NPPs should be carefully designed and interpreted considering possible detection bias.

Background: This study aimed to evaluate the reliability and validity of the self-administered questionnaire for Korean radiation workers. Methods: From May 24, 2016, to June 30, 2017, 20,608 participants completed the questionnaire, providing information on sociodemographics, lifestyle, work history and practices, medical radiation exposure, and medical history, which was linked to the National Dose Registry and the National Cancer Registry. The validity of the questionnaire was evaluated using the responses of 20,608 workers, and reliability was evaluated using the responses of 3043 workers who responded to the survey twice. Results: Responses concerning demographic characteristics and lifestyle showed reliability with a moderate-to-high agreement (kappa: 0.43–0.99), whereas responses concerning occupation and medical radiation exposure had a wide range of agreement (kappa: 0.05–0.95), possibly owing to temporal variability during employment. Regarding validity, responses to the question about the first year of employment had an excellent agreement with the national registry (intraclass correlation coefficient = 0.9); however, responses on cancer history had a wide range of agreement (kappa: 0.22–0.85). Conclusion Although the reliability and validity of the questionnaire were not distinguished by demographic characteristics, they tended to be low among participants whose occupational radiation exposure was minimal. Overall, the information collected can be reliable for epidemiological studies; however, caution must be exercised when using information such as medical exposure and work practices, which are prone to temporal variability.

BACKGROUND: Although histological diagnosis of pilomatricoma is not difficult because of its unique histological features, cytological diagnosis through fine-needle aspiration cytology (FNAC) is often problematic due to misdiagnoses as malignancy. METHODS: We reviewed the cytological features of 14 cases of histologically-proven pilomatricoma from Korea Cancer Center Hospital, with a discussion on the diagnostic pitfalls of FNAC. RESULTS: Among 14 cases of pilomatricoma, 10 (71.4%) were correctly diagnosed through FNAC, and two (14.3%) were misdiagnosed as carcinoma. Cytologically, all cases had easily recognizable clusters of basaloid cells and foreign body-type multinucleated cells. Although ghost cells were also found in all cases, some were inconspicuous and hardly recognizable due to their small numbers. CONCLUSIONS: An accurate diagnosis of pilomatricoma in FNAC is feasible with consideration of clinical information and close examination of ghost cells.
Biopsy, Fine-Needle ; Diagnosis ; Diagnostic Errors ; Korea ; Pilomatrixoma

BACKGROUND: Trophoblast antigen 2 (TROP2) is a human trophoblast cell-surface glycoprotein that is overexpressed in several types of epithelial cancers, and is suggested to be associated with an unfavorable prognosis. BRAF mutations are the most common genetic alteration in papillary thyroid carcinoma (PTC). We evaluated the correlation between TROP2 expression and BRAF mutation in PTC. METHODS: First, we carried out pyrosequencing for BRAF mutations and immunohistochemistry for TROP2 expression with a tissue microarray consisting of 52 PTC cases. Membranous staining in at least 5% of tumor cells was designated as positive staining and we analyzed the relationship between TROP2 expression and diverse clinicopathological factors, including BRAF mutation. Second, we tested TROP2 mRNA expression in three thyroid cancer cell lines with BRAF mutations (BCPAP, SNU790, and 8505C) and a normal thyroid cell line. Additionally, we checked TROP2 protein levels in a normal thyroid cell line after introduction of the BRAF V600E mutation. RESULTS: In this study, 21 of 26 cases with BRAF mutation showed TROP2 immunoreactivity, whereas all 26 cases without BRAF mutation showed no immunoreactivity for TROP2 with a statistically significant difference (p<.001). Upregulation of TROP2 mRNA was observed in all three thyroid cancer cell lines, but not in the normal thyroid cell line. Interestingly, however, the TROP2 expression was increased in the normal thyroid cell line after introduction of the BRAF V600E mutation. CONCLUSIONS: Based on these results, we concluded that TROP2 expression is significantly associated with BRAF mutation and that TROP2 immunohistochemistry could be used for predicting BRAF mutations or diagnosing papillary thyroid carcinoma.
Cell Line ; Glycoproteins ; Humans ; Immunohistochemistry ; Prognosis ; RNA, Messenger ; Thyroid Gland ; Thyroid Neoplasms ; Trophoblasts ; Up-Regulation

BACKGROUND: It is difficult to correctly diagnose follicular neoplasms (FNs) on fine-needle aspiration cytology (FNAC) because it shares many cytological features with other mimicking lesions. The aim of this study was to identify the cytological features that differentiate FNs from mimicking lesions. METHODS: We included the cytological slides from 116 cases of thyroid FN diagnosed on FNAC, and included their subsequent histological diagnoses. We evaluated the cytological architectural pattern and nuclear features of the lesions according to their histological groups. RESULTS: The final histological diagnoses of the 116 cases varied, and included 51 FNs (44%), 47 papillary thyroid carcinomas (40%) including follicular variant, and seventeen cellular nodular hyperplasias (15%). Regardless of the final histological diagnosis, microfollicular pattern was observed in most cases. On the other hand, trabecular pattern was identified in 34% of FNs, but not in any other lesions. Additionally, elongated nuclei and ground glass chromatin were found in only some papillary thyroid carcinomas. CONCLUSIONS: This study shows that the trabecular pattern is a representative cytological feature of FNs that can be used to distinguish FNs from mimicking lesions. In addition, nuclear shape and chromatin pattern can be used to further confirm the diagnosis of FNs from mimicking lesions through FNAC.
Biopsy, Fine-Needle ; Chromatin ; Diagnosis ; Diagnosis, Differential ; Glass ; Hand ; Hyperplasia ; Thyroid Gland ; Thyroid Neoplasms

Ionizing radiation is a well-known carcinogen, and is listed as one carcinogenic agent of occupational cancer. Given the increase in the number of workers exposed to radiation, as well as the increase in concern regarding occupational cancer, the number of radiation-related occupational cancer claims is expected to increase. Unlike exposure assessment of other carcinogenic agents in the workplace, such as asbestos and benzene, radiation exposure is usually assessed on an individual basis with personal dosimeters, which makes it feasible to assess whether a worker's cancer occurrence is associated with their individual exposure. However, given the absence of a threshold dose for cancer initiation, it remains difficult to identify radiation exposure as the root cause of occupational cancer. Moreover, the association between cancer and radiation exposure in the workplace has not been clearly established due to a lack of scientific evidence. Therefore, criteria for the recognition of radiation-related occupational cancer should be carefully reviewed and updated with new scientific evidence and social consensus. The current criteria in Korea are valid in terms of eligible radiogenic cancer sites, adequate latent period, assessment of radiation exposure, and probability of causation. However, reducing uncertainty with respect to the determination of causation between exposure and cancer and developing more specific criteria that considers mixed exposure to radiation and other carcinogenic agents remains an important open question.
Asbestos ; Benzene ; Consensus ; Humans ; Korea ; Radiation Exposure ; Radiation, Ionizing ; Uncertainty

BACKGROUND/AIMS: Cancer is known to be a disease by many factors. However, specific results of reprogramming by pluripotency-related transcription factors remain to be scarcely reported. Here, we verified potential effects of pluripotent-related genes in hepatocellular carcinoma cancer cells. METHODS: To better understand reprogramming of cancer cells in different genetic backgrounds, we used four liver cancer cell lines representing different states of p53 (HepG2, Hep3B, Huh7 and PLC). Retroviral-mediated introduction of reprogramming related genes (KLF4, Oct4, Sox2, and Myc) was used to induce the expression of proteins related to a pluripotent status in liver cancer cells. RESULTS: Hep3B cells (null p53) exhibited a higher efficiency of reprogramming in comparison to the other liver cancer cell lines. The reprogrammed Hep3B cells acquired similar characteristics to pluripotent stem cells. However, loss of stemness in Hep3B-iPCs was detected during continual passage. CONCLUSIONS: We demonstrated that reprogramming was achieved in tumor cells through retroviral induction of genes associated with reprogramming. Interestingly, the reprogrammed pluripotent cancer cells (iPCs) were very different from original cancer cells in terms of colony shape and expressed markers. The induction of pluripotency of liver cancer cells correlated with the status of p53, suggesting that different expression level of p53 in cancer cells may affect their reprogramming.
Carcinoma, Hepatocellular ; Cell Line ; Genetic Background ; Induced Pluripotent Stem Cells* ; Liver Neoplasms* ; Pluripotent Stem Cells ; Transcription Factors ; Zidovudine

PURPOSE: The Notch signaling pathway is widely expressed in normal, reactive, and neoplastic tissues; however, its role in thyroid tissues has not been fully elucidated. Therefore, this study was conducted to characterize the expression of the Notch signaling pathway in papillary thyroid cancer (PTC) cells and anaplastic thyroid cancer (ATC) cells. MATERIALS AND METHODS: Expression of activated Notch1 in ATC and PTC paraffin-embedded tissues was determined by immunohistochemistry. The small interfering RNA techniquewas employed to knock down Notch1 expression in ATC and PTC cell lines. RESULTS: The expression of activated Notch1 was higher in ATC cases than in PTC cases. Inhibition of Notch1 significantly reduced proliferation and migration of ATC cells, but not PTC cells. In addition, inhibition of Notch1 in ATC cells significantly reduced the expression of key markers of epithelial-mesenchymal transition and cancer stem cells. Conversely, changes in the expression of these proteins were not observed in PTC cells. CONCLUSION: The results of this study suggest that Notch1 expression plays different roles in tumor progression in ATC and PTC cells. We also found that Notch1 expression was significantly related to the highly invasive or proliferative activity of ATC cells.
Cell Line ; Epithelial-Mesenchymal Transition ; Immunohistochemistry ; Neoplastic Stem Cells ; RNA, Small Interfering ; Thyroid Carcinoma, Anaplastic* ; Thyroid Gland ; Thyroid Neoplasms

Curcumin protects the skin against radiation-induced epidermal damage and prevents morphological changes induced by irradiation skin, thereby maintaining the epidermal thickness and cell density of basal layers. In this study, the effects of topical curcumin treatment on radiation burns were evaluated in a mini-pig model. Histological and clinical changes were observed five weeks after radiation exposure to the back (⁶⁰Co gamma-radiation, 50 Gy). Curcumin was applied topically to irradiated skin (200 mg/cm²) twice a day for 35 days. Curcumin application decreased the epithelial desquamation after irradiation. Additionally, when compared to the vehicle-treated group, the curcumin-treated group showed reduced expression of cyclooxygenase-2 and nuclear factor-kappaB. Furthermore, irradiation prolonged healing of biopsy wounds in the exposed area, whereas curcumin treatment stimulated wound healing. These results suggest that curcumin can improve epithelial cell survival and recovery in the skin and therefore be used to treat radiation burns.
Biopsy ; Burns* ; Cell Count ; Curcumin* ; Cyclooxygenase 2 ; Epithelial Cells ; Radiation Exposure ; Skin ; Wound Healing ; Wounds and Injuries

Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation.
DNA Damage/drug effects ; Environmental Exposure ; Humans ; Leukemia/epidemiology/etiology ; Neoplasms, Radiation-Induced/epidemiology ; *Radiation Dosage ; Radiation Tolerance ; *Radiation, Ionizing ; Radioactive Hazard Release ; Risk