High expression of G protein subunit gamma 13 is associated with poor prognosis of gastrointestinal stromal tumor.

The G protein subunit gamma 13 (GNG13) plays an important role in olfaction, vision, and biological behavior. However, our knowledge of the relationship between GNG13 expression and the clinicopathological features of gastrointestinal tumors is insufficient. Therefore, we used the Oncomine database to evaluate the expression of GNG13 mRNA in gastric cancer, the result showed that there was no significant difference in the expression of GNG13 between gastric cancer and adjacent normal tissues, and GNG13 mRNA expression was assessed in 32 matched pairs of Gastrointestinal adenocarcinoma tissues and adjacent normal tissues as well as 32 matched pairs of gastrointestinal stromal tumor (GIST) and adjacent normal tissues by quantitative reverse transcription-polymerase chain reaction analysis. The results suggested that GNG13 is upregulated in gastrointestinal stromal tumors. Immunohistochemical analysis was used to detect the GNG13 in the tissues of 123 patients with GIST. High cytoplasmic expression of GNG13, which was observed in 65.85 % of GIST patients, significantly correlated with mitotic index(P = 0.036) and tumor size(P = 0.024). Multiple logistic regression analysis showed that the expression of GNG13 was significantly associated with tumor size. Kaplan-Meier analysis indicated that high GNG13 expression was associated with poor prognosis of GIST. Multivariate Cox regression analysis indicated that the expression of GNG13, mitotic index and tumor size were independent adverse prognostic factors of GIST. These findings suggest that GNG13 is associated with the malignant phenotype of GIST and may serve as a marker of poor prognosis.