Transcriptomic Profiling on Localized Gastric Cancer Identified CPLX1 as a Gene Promoting Malignant Phenotype of Gastric Cancer and a Predictor of Recurrence after Surgery and Subsequent Chemotherapy

Abstract

AbstractLocalized gastric cancer (GC) becomes fatal once recurring. We still have room for improving their prognoses. Firstly, a transcriptomic analysis was done on surgically resected specimens of 16 patients with UICC stage III GC who underwent curative gastrectomy and adjuvant oral fluoropyrimidine monotherapy. Four of them were free from disease for longer than 5 years, and the others experienced 15 metachronous metastasis at either liver, peritoneum, or distant lymph nodes (n = 4 each) within 2 years after surgery. CPLX1 was identified as a novel oncogene candidate for recurrence among 57,749 genes. Secondary, we tested alteration of malignant phenotypes including drug resistance of gastric cancer cell lines by small interfering RNA-mediated CPLX1 knockdown. Inhibiting CPLX1 expression decreased the proliferation, motility, and invasiveness of GC cells, and increased apoptosis and sensitivity to fluorouracil. Thirdly, we validated the clinical significance of CPLX1 expression in GC by quantitative RT-PCR on 180 primary gastric cancer tissues of which patients underwent gastric resection for stage II and III GC without preoperative treatment between 2001 and 2014. Increased expression of CPLX1 mRNA in gastric cancer tissues correlated with worse prognoses and was an independent risk factor for peritoneal recurrence in subgroups receiving adjuvant chemotherapy. CPLX1 may represent a biomarker for recurrence of gastric cancer and a target for therapy.Brief descriptionTranscriptomic analysis identified CPLX1 gene as a novel oncogene candidate for gastric cancer. CPLX1 may promote epithelial-mesenchymal transition and evading apoptosis of gastric cancer cells even under a cytotoxic agent, and also be a predictor for recurrence after surgery for UICC Stage II-III gastric cancer.