Phosphoserine Phosphatase Is a Novel Prognostic Biomarker on Chromosome 7 in Colorectal Cancer.

Amplification of chromosome 7p (Ch.7p) is common in colorectal cancer (CRC). The aim of this study was to identify potential driver genes on Ch.7p that are overexpressed due to DNA copy number amplification and determine their clinical significance in CRC. We identified phosphoserine phosphatase (PSPH) as a potential driver gene using a CRC dataset from The Cancer Genome Atlas (TCGA) using a bioinformatics approach. The expression of PSPH in 124 primary CRCs was examined by quantitative reverse transcription polymerase chain reaction (PCR) and immunohistochemistry. The biological effect of PSPH expression was explored by Gene Set Enrichment Analysis (GSEA) using the TCGA dataset. PSPH was overexpressed in tumor tissues and PSPH positively correlated with depth of invasion and distant metastasis. On multivariate analysis, high PSPH expression was an independent poor prognostic factor. These results were supported by GSEA. PSPH could be a novel prognostic biomarker with malignant potential on Ch.7p in CRC.