A novel tumor suppressing gene, ARHGAP9, is an independent prognostic biomarker for bladder cancer

Screening for genes or markers relevant to bladder cancer (BC) tumorigenesis and progression is of vital clinical significance. The present study used reverse-transcription quantitative PCR reaction assays to examine the expression of mRNA encoding Rho GTPase-activating protein 9 (ARHGAP9) in BC tissue samples and to determine whether ARHGAP9 is an independent prognostic biomarker for non-muscle invasive BC (NMIBC) and muscle invasive BC (MIBC). The results revealed that the downregulation of ARHGAP9 expression in the tissue of patients with NMIBC or MIBC was significantly associated with a poor prognosis. In patients with NMIBC, a high expression of ARHGAP9 was significantly associated with prolonged recurrence-free survival, whereas in MIBC patients, it was significantly associated with an increased progression-free and cancer-specific survival. The risk of cancer-specific death was 2.923 times higher (95% confidence interval, 1.192–7.163) when ARHGAP9 levels were decreased. In conclusion, lower expressions of ARHGAP9 correlated with BC prognosis, indicating that it may be a useful marker for guiding treatment application.