Efficacy of Endoscopic Resection for Rectal Neuroendocrine Tumors Smaller than 15 mm.

BACKGROUND: Local resection, including endoscopic resection, is recommended for rectal neuroendocrine tumors (NETs) < 15 mm in patients without risk factors for metastasis, though the short- and long-term outcomes are unclear. AIMS: This study investigates the efficacy of endoscopic resection for rectal NETs < 15 mm. METHODS: The short- and long-term outcomes of patients with rectal NETs < 15 mm who underwent endoscopic resection and the outcomes of each endoscopic technique were analyzed. The tumors were stratified as < 10 mm (small-size group, SSG) and 10-14 mm (intermediate-size group, IMG). RESULTS: Overall, 139 lesions (SSG, n = 118; IMG, n = 21) were analyzed. All tumors were classified as G1 (n = 135) or G2 (n = 4) according to the 2019 World Health Organization grading criteria. The complete resection rate was not different between the groups (P = 0.151). Endoscopic submucosal dissection (ESD) and endoscopic submucosal resection with a ligation device (ESMR-L) achieved complete resection rates > 90% in the SSG. The ESMR-L procedure time (P < 0.001) and hospitalized period (P < 0.001) were significantly shorter than those of ESD. ESD achieved a complete resection rate of 80.0% in the IMG. The tumor size did not affect the overall survival or rate of lymph node/distant metastases. CONCLUSIONS: Endoscopic resection is a feasible and effective treatment for patients with rectal NETs < 15 mm without the risk factors of metastasis. ESMR-L and ESD are optimal techniques for resecting tumors smaller than 10 mm and 10-14 mm, respectively.

Identification of promoter region of ghrelin gene in human medullary thyroid carcinoma cell line.

Ghrelin, an endogenous ligand for growth hormone (GH) secretagogue receptor, stimulates GH secretion. The ghrelin gene is expressed most abundantly in stomach. The mRNA is also detected in other tissues and cell lines. However, the mechanism of the transcriptional regulation of the ghrelin gene has not yet been clarified. In the present study, we have investigated the regulatory region of the ghrelin gene expression in the human medullary thyroid carcinoma cell line (TT cells). PCR analysis of the 5'-region for human ghrelin gene revealed the presence of the first exon corresponding to the short non-coding first exon of the mouse ghrelin gene. The first exon is located at the 502 bp upstream from the 5'-end of the formerly reported human ghrelin gene. RT-PCR analysis showed the expression of the first exon in the stomach and TT cells. The expression of the first exon in the human stomach was confirmed by 5'-RACE method. Significant level of promoter activity was observed in the 1225-1107 bp up-stream region of the translation initiation site by luciferase assay. Specific protein binding to the promoter region of -1129 to -1100 was detected by electrophoretic mobility shift assay with nuclear extract from TT cells. These results suggest that the ghrelin gene expression in TT cells might be regulated by the upstream region of the first exon.