Glyceraldehyde-3-phosphate dehydrogenase is overexpressed in colorectal cancer onset

Abstract

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an essential regulator of glycolysis used as a housekeeping marker for gene/protein normalisation. Given the pivotal role of GAPDH in tumour metabolism, our aim was to correlate its protein expression with tumour staging and prognosis of colorectal cancer. GAPDH expression was immunohistochemically analysed in tumour tissues from 62 colorectal cancer (CRC) patients, and validated at mRNA level in an independent dataset comprising 98 paired stage II CRC and normal samples. Staining quantification was performed by computational image analysis, and correlations between GAPDH expression and tumour progression stage were assessed. Gene expression profiling was performed using Affymetrix microarrays. Probability of patient survival and disease-free survival were analysed by the univariate product-limit method of Kaplan-Meier. Groups were compared using Kruskal-Wallis tests. Overexpression of GAPDH is positively associated with early stage tumours without regional lymph node and distant metastases involved. These results were reinforced by those obtained at mRNA level. Studying the role of GAPDH in malignant transformation can shed new light on the understanding of tumour onset and lead to the design of more efficient personalised therapies.