Clinicopathological significance of intestinal metaplasia in endoscopically resected early gastric carcinoma.

OBJECTIVE: To investigate the clinicopathological and prognostic significance of intestinal metaplasia (IM) in endoscopically resected early gastric carcinoma (EGC). METHODS: Altogether 136 consecutive cases with EGC resected by endoscopic submucosal dissection over 5 years were included and divided into the early gastric cardiac (EGCC; n = 60) and non-cardiac carcinoma (EGNCC; n = 76) groups. Goblet cell IM and subtypes were determined with histology and immunostaining. Recurrence-free survival (RFS) was compared among various IM groups. RESULTS: IM was identified in 128 (94.1%) EGC cases, including complete IM (n = 39), incomplete IM (n = 27), and mixed IM (n = 62). Incomplete IM was significantly more common in EGCC and exhibited a lower frequency of en bloc resection than the complete subtype. The frequency of synchronous or metachronous gastric tumor was significantly more common in EGCC with complete IM than in those with incomplete IM. Compared to EGC without IM, EGC with IM showed a significantly higher frequency of non-poorly cohesive carcinoma, en bloc resection, and non-eCuraC-1 grade. EGNCC with IM was significantly associated with negative resection margins and en bloc resection. The 5-year RFS was significantly lower in EGNCC patients with incomplete IM compared with those with mixed IM. The independent risk factors for RFS included tumor size >2 cm and eCuraC-1 grade. CONCLUSIONS: Subtyping IM in EGC helped predict endoscopic resectability, prognosis, and risk of synchronous or metachronous gastric tumor. The significance of IM differed between EGCC and EGNCC. Large studies with longer follow-up are warranted to validate our findings.

Long non-coding RNA ELFN1-AS1-mediated ZBTB16 inhibition augments the progression of gastric cancer by activating the PI3K/AKT axis.

Long non-coding RNA ELFN1 antisense RNA 1 (ELFN1-AS1) has been reported as a cancer driver in many human malignancies. This study was conducted to investigate the function of ELFN1-AS1 in gastric cancer (GC) and its mechanism of action. Bioinformatics analysis revealed increased expression of ELFN1-AS1 in GC, and abundant expression of ELFN1-AS1 was observed in the acquired GC cell lines. Knockdown of ELFN1-AS1 in GC cells weakened cell proliferation, invasion, migration, and resistance to apoptosis. ELFN1-AS1 was mainly localized in the nuclei of GC cells. ELFN1-AS1 recruited DNA methyltransferases to the promoter region of ZBTB16 and induced transcriptional repression of ZBTB16 through methylation modification. Furthermore, downregulation of ZBTB16 activated the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway and restored the proliferation and invasiveness of GC cells. In vivo, downregulation of ELFN1-AS1 reduced the growth rate of xenograft tumors in mice. In summary, this study demonstrates that ELFN1-AS1 recruits DNA methyltransferases to the promoter region of ZBTB16 to induce its transcriptional repression, which further augments the development of GC by activating the PI3K/AKT signaling pathway.