Prostate cancer (PCa) metastasis is considered the leading cause of cancer death in males. Therapeutic strategies and diagnosis for stage-specific PCa have not been well understood. Rho guanine nucleotide exchange factor 38 (ARHGEF38) is related to tumor cell polarization and is frequently expressed in PCa. Microarray data of PCa were downloaded from GEO and TCGA databases. A total of 243 DEGs were screened, of which, 32 genes were upregulated. The results of enrichment analysis showed the participation of these DEGs in the tumor cell metastasis pathway. ARHGEF38 was significantly up-regulated in the four most prevalent cancers worldwide (p < 0.05), and its expression was higher in the tumor samples with higher Gleason score (GS). IHC, qRT-PCR, and western-blot analyses showed the higher expression of ARHGEF38 in PCa than benign prostatic hyperplasia (BPH). In addition, IHC results demonstrated a higher expression of ARHGEF38 in high-grade PCa than the low-grade PCa.