Pituitary tumor-transforming gene-1 serves as an independent prognostic biomarker for gastric cancer

Abstract

Background: Pituitary tumor-transforming gene-1 (PTTG1) is a transcription factor that can affect transcriptional activity, angiogenesis, and cell senescence. We examined PTTG1 mRNA and protein expression in gastric cancer (GC) cell lines and tissues to determine its value as a biomarker for GC diagnosis and therapy. Methods: PTTG1 mRNA expression from 78 GC cases and paired adjacent normal mucosa (PCR cohort) as well as from five gastric cell lines was assessed using qRT-PCR. Nuclear and cytoplasmic RNA were extracted from two gastric cell lines to determine PTTG1 mRNA localization. PTTG1 protein expression from 98 GC cases, their paired adjacent normal mucosa, and 23 gastric intraepithelial neoplasia (GIN) cases was examined using immunohistochemistry (IHC cohort). The correlation between PTTG1 mRNA and protein expression and GC clinicopathological parameters was analyzed. Results: PTTG1 mRNA expression in GC tissues and cell lines was significantly increased compared with adjacent normal gastric mucosa and normal gastric mucous cell lines (p < 0.05). PTTG1 expression was nuclear and cytoplasmic, with higher cytoplasmic expression. PTTG1 immunostaining significantly differed in GC (95.66 ± 20.65), GIN (84.00 ± 34.16), and normal adjacent mucosa (28 ± 22.25) (p < 0.001). Multivariate Cox regression analysis revealed that PTTG1 mRNA and protein expression are independent prognostic factors for GC patient survival. Conclusion: Our results suggest that PTTG1 is a promising target for GC diagnosis and therapy.