ABSTRACT: Pancreatic cancer is the fourth leading cancer-related death in United States. The clinical relevance of genomic imbalances in pancreatic cancer is uncertain. We performed array-comparative genomic hybridization (aCGH) in 44 resected pancreatic cancer specimens from a Korean cohort. We observed recurrent copy number gains were observed in chromosome 1q, 11q, 18q11.1-11.2, and 20q13.13; and losses in chromosome 2p, 9p, 10q, 14q, 15q, 18q12.2-23, 19q, 20q11.1, 21p, and 22q. High copy number gains, with log2 ratio >2.0, were observed in 4 cytobands, encoding genes such as G protein-coupled receptor 48, c-myc and gamma-catenin. By comparing the aCGH results of long survivors and short survivors, determined according to the median survival, we observed that loss of cytoband 18q22.3, encoding 5 genes, was the only alteration with significantly different frequencies. The copy number of the CPGL (Carboxypeptidase of glutamate-like) gene in cytoband 18q22.3 was found to be significantly associated with overall survival in univariate analyses (p=0.019 by log-rank test). This was subsequently assessed in the Italian cohort: 41 out of the 61 specimens carried deletion of the CPGL gene. Patients with deletion of the CPGL gene also had shorter overall survival (p=0.003 by log-rank test). Multivariate analysis of the two cohorts combined showed that loss of 18q22.3 / deletion of the CPGL gene was an independent poor prognostic factor for overall survival after adjusting for other factors which were found to impact the outcome (hazard ratio 2.72, p=0.0007). overexpression of the CPGL or its alternating splicing isoform CPGL-B in a pancreatic cancer cell lines resulted in slower proliferation of cells, G1 cell cycle arrest, and reduced migration activity. In conclusion, through aCGH analysis, we identified loss of 18q22.3 / deletion of the CPGL gene as potentially being an independent poor prognostic factor in resected pancreatic cancer. We further identified the CPGL gene as a potential tumor suppressor for pancreatic cancer cell lines.
