Clinical Significance of CLDN18.2 Expression in Metastatic Diffuse-Type Gastric Cancer

• Published in: Journal of gastric cancer 2020, Vol.20 (4), p.408-420
• Main Authors: Kim, Seo Ree, Shin, Kabsoo, Park, Jae Myung, Lee, Han Hong, Song, Kyo Yong, Lee, Sung Hak, Kim, Bohyun, Kim, Sang-Yeob, Seo, Junyoung, Kim, Jeong-Oh, Roh, Sang-Young, Kim, In-Ho
• Format: Article
• Language: Korean
• ISSN: 2093-582X; 2093-5641

Purpose: Isoform 2 of tight junction protein claudin-18 (CLDN18.2) is a potential target for gastric cancer treatment. A treatment targeting CLDN18.2 has shown promising results in gastric cancer. We investigated the clinical significance of CLDN18.2 and other cell-adherens junction molecules (Rho GTPase-activating protein [RhoGAP] and E-cadherin) in metastatic diffuse-type gastric cancer (mDGC). Materials and Methods: We evaluated CLDN18.2, RhoGAP, and E-cadherin expression using two-plex immunofluorescence and quantitative data analysis of H-scores of 77 consecutive mDGC patients who received first-line platinum-based chemotherapy between March 2015 and February 2017. Results: CLDN18.2 and E-cadherin expression was significantly lower in patients with peritoneal metastasis (PM) than those without PM at the time of diagnosis (P=0.010 and 0.013, respectively), whereas it was significantly higher in patients who never developed PM from diagnosis to death than in those who did (P=0.001 and 0.003, respectively). Meanwhile, CLDN18.2 and E-cadherin expression levels were significantly higher in patients with bone metastasis than in those without bone metastasis (P=0.010 and 0.001, respectively). Moreover, we identified a positive correlation between the expression of CLDN18.2 and E-cadherin (P