Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy with 
high recurrence and poor prognosis duo to the lack of effective biomarkers. TBC1 
domain family member 16 (TBC1D16), a GTPase-activating protein, is involved in 
regulating intracellular trafficking in tumorigenesis and metastasis. However, 
the clinical significance of TBC1D16 in EOC remains unknown. In the present 
study, we investigated the expression and prognostic significance of TBC1D16 in 
EOC and its relationship with the expression of vascular endothelial growth 
factor (VEGF). The tissue specimens included 156 histologically confirmed EOC 
and 30 normal ovarian tissues. The expression of TBC1D16 and VEGF was detected 
by immunohistochemistry (IHC), and the immunoreactive score was calculated with 
signal intensity and percentage of positive cells. IHC results showed that 
TBC1D16 and VEGF were both mainly localized in cytoplasm of epithelial cells in 
normal ovarian tissues and were expressed in cancer cells. Based on the 
immunoreactive score, TBC1D16 expression in EOC was categorized as "high 
expression," compared with normal ovarian tissues (P < 0.05). The Chi-square 
test showed that high TBC1D16 expression was related to advanced pT stages (P = 
0.029), but not correlated with other clinical features. Moreover, the TBC1D16 
expression was significantly higher in EOC specimens with low VEGF expression (P 
< 0.001). Importantly, in both univariate and multivariate survival analyses, 
high expression of TBC1D16 was significantly correlated with good overall 
survival (OS). In conclusion, TBC1D16 is a predictive marker for favorable 
prognosis of EOC.