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Anaplastic thyroid carcinoma (ATC) is a rare type of thyroid carcinoma with a poor prognosis. Thus, suitable preclinical tumor models are required for the development of new ATC therapies. In the present study, orthotopic tumor xenograft models were established using ATC cell lines and SCID mice, and tumor invasion and the effects of anticancer drugs were evaluated using positron emission tomography/computed tomography (PET/CT) to repeatedly and non-invasively monitor these models. Three ATC cell lines (8305c, 8505c, and ACT-1) were used. Their sensitivities to two anticancer drugs (paclitaxel and lenvatinib) were investigated. The 8505c cell line was orthotopically implanted into SCID mice, which were then divided into three groups: no chemotherapy, paclitaxel (5 mg/kg, administered intraperitoneally, every week), and lenvatinib (5 mg/kg, oral route, every day) groups. PET/CT was performed and tumor growth and the effects of anticancer drugs based on tumor volume and fludeoxyglucose (FDG) uptake were evaluated. 8505c cells exhibited the highest sensitivity to the anticancer drugs. In mice implanted with 8505c cells, continuous increases in FDG uptake associated with tumor growth were detected on PET/CT in the group that received no chemotherapy. The tumor volume and FDG uptake increased by 91.5- and 2.4-fold, respectively, within 2 weeks. The increase observed in tumor volume was 26.9- and 12.2-fold in the paclitaxel and lenvatinib groups, respectively, within 2 weeks. Furthermore, the increase in FDG uptake was 1.8-fold and 1.6-fold in the paclitaxel and lenvatinib groups, respectively, within 2 weeks. In our orthotopic SCID mouse model, tumor growth and the effects of anticancer drugs were repeatedly and non-invasively monitored using PET/CT. The present method is useful for the development of new ATC treatments.

Endoscopic surgery has been introduced in various surgical fields. Endoscopic surgery requires different skills from open surgery due to the restricted surgical field and difficulty in identifying anatomical structures from certain viewpoints. Therefore, surgeons need to undergo sufficient surgical training before performing such surgery in the clinical setting. We examined the utility of fresh frozen human cadavers for surgical training aimed at introducing video-assisted neck surgery (VANS) at our department. First, we performed surgical training using fresh human cadavers four times. Next, we performed hemi-thyroidectomy with VANS in 5 clinical patients. After the cadaver training and the actual surgery, the surgeons evaluated each step of the surgical procedure using a 3-point scale. In the cadaver training, the scores for steps : creation of a subcutaneous tunnel and lifting up the skin flap and pre-thyroid muscles were higher than other steps. And a tracheal injury occurred as a complication. However, we were able to recognize anatomical structures under the endoscopic view. And it was also useful for confirming the role of surgical staff and simulating the placement of surgical equipment. Surgical training using fresh frozen human cadavers was effective at introducing a new surgical method.

Background and Objectives: In a previous genome-wide screening, we identified hypermethylated CpG islands around glutamate decarboxylase 1 (GAD1) in lung adenocarcinoma (LADC). In this study, we aimed to investigate the methylation and expression status of GAD1 and its prognostic value in patients with LADC. Methods: GAD1 methylation and mRNA expression status were analyzed using 33 tumorous and paired non-tumorous LADC samples and publicly available datasets. The prognostic value of GAD1 overexpression was investigated using publicly available datasets of mRNA levels and 162 cases of LADC by immunohistochemistry. Results: The methylation and mRNA expression levels of GAD1, each having a positive correlation, were significantly higher in LADC tumors than in paired non-tumorous tissues. LADC patients with higher GAD1 mRNA expression showed significantly poorer prognosis for overall survival in publicly available datasets. Higher immunoreactivity of GAD1 was significantly associated with the pathological stage, pleural invasion, lymph vessel invasion, and poorer prognosis for cancer-specific and disease-free survival. Multivariate analysis revealed that GAD1 protein overexpression is an independent prognosticator for disease-free survival. Conclusions: GAD1 mRNA and protein expression levels were significant prognostic factors in LADC, suggesting that they might be useful biomarkers to stratify patients with worse clinical outcome after resection.

Background: Indocyanine green (ICG) accumulates in hepatocellular carcinoma (HCC), and tumor fluorescence can be observed under irradiation with near infrared light (NIR). This study investigated the clinical utility of ICG fluorescence imaging during resection of pulmonary metastases of HCC. Methods: From April 2010 to June 2018, six patients with suspected pulmonary metastasis of HCC were enrolled prospectively. Prior to surgery, all patients underwent the ICG hepatic function test following intravenous administration of ICG (0.5 mg/kg body weight). During surgery, metastatic HCC was identified by observation of ICG fluorescence, allowing assessment of the surgical margin. Tumor fluorescence was also evaluated on cut sections. Results: A total of 11 metastatic HCCs were resected in six patients at nine operations. Eight lesions were removed by wedge resection and 3 lesions were managed by lobectomy. During surgery, tumor fluorescence could be confirmed through the visceral pleura in 6 out of 7 lesions treated by wedge resection, while NIR irradiation was difficult for 1 lesion. For these 6 lesions, the median distance from the tumor to the visceral pleura and the median surgical margin were 0 mm (range, 0–2 mm) and 14 mm (range, 11–17 mm), respectively. When cut sections were examined, all tumors emitted fluorescence. All lesions were histologically confirmed to be metastatic HCC. Conclusions: In patients with pulmonary metastasis of HCC, ICG fluorescence imaging is useful for identifying the tumor and securing its margin when the lesion is peripheral and wedge resection is planned.

Our previous study reported that the DNA methylation of growth hormone secretagogue receptor (GHSR) was significantly higher in thymoma or thymic carcinoma (TC) than in normal thymic tissue samples. Thymic epithelial tumors (TETs) with higher GHSR DNA methylation were associated with significantly worse prognosis than those with lower levels of DNA methylation. Diversified components of the ghrelin‑GHSR axis may exert opposing effects in cancer progression, depending on the cancer type in question. However, the precise function of the axis remains unclear. In the present study, the mRNA expression of five key components of the ghrelin system [native ligand ghrelin, variant ligand In‑1 ghrelin, native receptor GHSR1a, variant receptor GHSR1b and acylation enzyme ghrelin O‑acyltransferase (GOAT)] were examined in 58 TET samples by reverse transcription‑quantitative PCR, and protein expression of GHSR1a and GHSR1b was assessed in 20 TETs using immunohistochemistry. The results revealed that In‑1 ghrelin, GHSR1b (variant forms) and GOAT were more strongly expressed in thymoma compared with thymic‑adjacent tissue. By contrast, no significant differences were observed in the expression of ghrelin and GHSR1a (native forms) between thymoma and thymic tissue. The mRNA expression of In‑1 ghrelin and GHSR1b (variant forms) was positively associated with GHSR methylation in thymoma tissue samples. However, a relationship was not found between ghrelin, GHSR1a or GOAT expression (native forms) and GHSR methylation in thymoma. Immunohistochemical analysis revealed that mRNA expression of GHSR1a and GHSR1b generally correlated with expression of the corresponding protein, and that the expression of GHSR1b was increased in advanced‑stage TETs. These results indicate that the DNA methylation of GHSR is associated with a shift from native expression (ghrelin and GHSR1a) to variant expression (In‑1 ghrelin and GHSR1b), which induces the tumorigenesis of thymoma, but not TC.

Thymic epithelial tumors (TETs) comprise thymomas and thymic carcinoma (TC). TC has more aggressive features and a poorer prognosis than thymomas. Genetic and epigenetic alterations in thymomas and TC have been investigated in an attempt to identify novel target molecules for TC. In the present study, genome‑wide screening was performed on aberrantly methylated CpG islands in thymomas and TC, and the glutamate decarboxylase 1 gene (GAD1) was identified as the 4th significantly hypermethylated CpG island in TC compared with thymomas. GAD1 catalyzes the production of γ‑aminobutyric acid from L‑glutamic acid. GAD1 expression is abundant in the brain but rare in other tissues, including the thymus. A total of 73 thymomas and 17 TC tissues were obtained from 90 patients who underwent surgery or biopsy at Tokushima University Hospital between 1990 and 2017. DNA methylation was examined by bisulfite pyrosequencing, and the mRNA and protein expression levels of GAD1 were analyzed using reverse transcription‑quantitative PCR and immunohistochemistry, respectively. The DNA methylation levels of GAD1 were significantly higher in TC tissues than in the normal thymus and thymoma tissues, and GAD1 methylation exhibited high sensitivity and specificity for discriminating between TC and thymoma. The mRNA and protein expression levels of GAD1 were significantly higher in TC tissues than in thymomas. Patients with TET with high GAD1 DNA hypermethylation and high mRNA and protein expression levels had significantly shorter relapse‑free survival rates than those with low levels. In conclusion, significantly more epigenetic alterations were observed in TC tissues compared with in thymomas, which may contribute to the clinical features and prognosis of patients.

In this study, we aimed to identify novel drivers that would be epigenetically altered through aberrant methylation in early-stage lung adenocarcinoma (LADC), regardless of the presence or absence of tobacco smoking-induced epigenetic field defects. Through genome-wide screening for aberrantly methylated CpG islands (CGIs) in 12 clinically uniform, stage-I LADC cases affecting six non-smokers and six smokers, we identified candidate tumor-suppressor genes (TSGs) inactivated by hypermethylation. Through systematic expression analyses of those candidates in panels of additional tumor samples and cell lines treated or not treated with 5-aza-deoxycitidine followed by validation analyses of cancer-specific silencing by CGI hypermethylation using a public database, we identified TRIM58 as the most prominent candidate for TSG. TRIM58 was robustly silenced by hypermethylation even in early-stage primary LADC, and the restoration of TRIM58 expression in LADC cell lines inhibited cell growth in vitro and in vivo in anchorage-dependent and -independent manners. Our findings suggest that aberrant inactivation of TRIM58 consequent to CGI hypermethylation might stimulate the early carcinogenesis of LADC regardless of smoking status; furthermore, TRIM58 methylation might be a possible early diagnostic and epigenetic therapeutic target in LADC.