Abstract 4101: Clinical significance of ZEB1 mRNA levels in peritoneal washing for gastric cancer
Authors: Yabusaki Norimitsu , Yamada Suguru , Murai Toshifumi , Kanda Mitsuro , Kobayashi Daisuke , Tanaka Chie , Fujii Tsutomu , Nakayama Goro , Sugimoto Hiroyuki , Koike Masahiko , Nomoto Shuji , Fujiwara Michitaka , Kodera Yasuhiro 
Published: August 2015

Abstract
Backgrounds.
ZEB1 affects cancer progression by regulating Epithelial to mesenchymal transition (EMT) in some cancers. In gastric cancer, ZEB1 expression in cancer tissue has been identified as an independent prognostic factor. We also reported on a significant correlation between ZEB1 expression and diffuse phenotype in gastric cancer, and that patients with high ZEB1 expression had significantly poorer survival than those with low expression. It was also reported that ZEB1 was an independent predictor of peritoneal dissemination in gastric cancer patients, and was expressed in disseminated cancer cells in the peritoneum in the same pattern as that seen in primary lesions. Therefore, we hypothesized that ZEB1 mRNA levels in peritoneal washing (pZEB1) in conjunction with peritoneal washing cytology might predict intraperitoneal recurrence and prognosis.
Objectives.
The association between pZEB1 and clinicopathological parameters, and prognosis was investigated, and the possibility of using pZEB1 as a predictive marker was explored in this study. To our knowledge, this is the first study to examine the clinical implication of pZEB1 in gastric cancer.
Methods.
One hundred and seven consecutive patients with gastric cancer, who underwent surgical procedures that included the collection of peritoneal washing samples at the left subphrenic area at the beginning of surgery, were enrolled. RT-PCR was performed to quantify ZEB1 mRNA levels in peritoneal washing (pZEB1). The correlation between pZEB1 and clinicopathological variables and recurrence were statistically analyzed.
Results.
Patients were classified into the pZEB1High group (n = 27) or the pZEB1Low group (n = 80) based on their pZEB1 expression. pZEB1 was statistically correlated with pathological T category (P = 0.03) and vessel involvement (P = 0.03). 5-year disease-specific survival was 36.4% for the pZEB1High group and 64.7% for the pZEB1Low group (P = 0.02), and disease-free survival with the exception of StageIV disease was 46.9% for the pZEB1High group and 83.0% for the pZEB1Low group (P = 0.03). When subclassified into 4 categories based on washing cytology and pZEB1, the survival was worse in the pZEB1High group than in the pZEB1Low group (CY0 group: P = 0.01; CY1 group: P = 0.13). The recurrence rate for the pZEB1High group (8/27) was significantly higher than that of the pZEB1Low group (10/80; P = 0.03). Of these 18 patients, 6 developed to lymph node metastases, 6 peritoneal metastases, 5 liver metastases, and 1 lung metastasis. However, our results failed to show the statistical correlation between pZEB1 and peritoneal dissemination and peritoneal recurrence.
Conclusions.
pZEB1 could be a predictive marker for poor prognosis or tumor aggressiveness in gastric cancer in the same way as ZEB1 expression does so in primary lesions. It could add valuable information to conventional peritoneal washing cytology, and thus help select candidates for more powerful chemotherapies.
Citation Format: Norimitsu Yabusaki, Suguru Yamada, Toshifumi Murai, Mitsuro Kanda, Daisuke Kobayashi, Chie Tanaka, Tsutomu Fujii, Goro Nakayama, Hiroyuki Sugimoto, Masahiko Koike, Shuji Nomoto, Michitaka Fujiwara, Yasuhiro Kodera. Clinical significance of ZEB1 mRNA levels in peritoneal washing for gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4101. doi:10.1158/1538-7445.AM2015-4101