Overexpression of GDP dissociation inhibitor 1 gene associates with the invasiveness and poor outcomes of colorectal cancer

GDP dissociation inhibitor (<i>GDI)</i> regulates the GDP/GTP exchange reaction of most Rab proteins by inhibiting GDP dissociation. This study evaluated the potential prognostic and predictive value of <i>GDI1</i> in colorectal cancer (CRC). To address the prognostic power of <i>GDI1</i>, we performed individual and pooled survival analyses on six independent CRC microarray gene expression datasets. <i>GDI1</i>-enriched signatures were also analyzed. Kaplan–Meier and Cox proportional analyses were employed for survival analysis. An immunohistochemistry (IHC) analysis was performed to validate the clinical relevance and prognostic significance of the GDI1 protein level in CRC tissue samples. The results revealed that <i>GDI1</i> mRNA level was significantly linked with the aggressiveness of CRC, which is compatible with gene set enrichment analysis. A meta-analysis and pooled analysis demonstrated that a higher mRNA <i>GDI1</i> expression was dramatically correlated with a worse survival in a dose-dependent manner in CRC patients. Further IHC analysis validated that the protein expression of GDI1 in both cytoplasm and membrane also significantly impacted the outcome of CRC patients. In CRC patients with stage III, chemotherapy significantly reduced the relative risk of death in low-<i>GDI1</i> subgroup (hazard ratio (HR) = 0.22; 95% confidence interval (95% CI) 0.09–0.56, <i>p</i> = 0.0003), but not in high-<i>GDI1</i> subgroup (HR = 0.63; 95% CI 0.35–1.14, <i>p</i> = 0.1137). Therefore, both high mRNA and protein levels of GDI1 were significantly related to poor outcomes in CRC patients. <i>GD11</i> may serve as a prognostic biomarker for CRC.