Human arrest defective 1 (hARD1) is an acetyltransferase; its physiological significance remains unclear. To explore the relationship between ARD1 protein and tumors, we detected the hARD1 protein in tumor tissues in vivo. We cloned hARD1 gene from Hela cell and construct recombinant plasmid pET28b-hARD1. The recombinant plasmid was transformed into E. coli BL21 (DE3)plysS. hARD1 protein was expressed by inducing with IPTG(1 mmol/L) and purified up to 95% through Ni2+ chelation affinity chromatography. We used the purified hARD1 protein as antigen immunized the Balb/c mice and obtained the hARD1 specific polyclonal antiserum. Through immunohistochemical analysis of different tumor tissues in vivo, we found that hARD1 expressed at high frequency in breast cancer, prostate cancer and lung cancer, especially, hARD1 expression frequency in breast cancer was up to 70%, which is higher than in the other tumors. These results indicate that the high expression level of hARD1 could be an indicator of the breast cancer. This new finding would be a foundation to further explore the relationship between breast tumor and hARD1.