Breast cancer is the most frequent malignancy among females. In this study, we analyzed the expression pattern of a homeobox gene (HOXD10) in human invasive ductal breast cancer tissues and normal tissues. With the ACTB (β-actin) gene as a reference, HOXD10 was detected in 60 breast cancer tissues by using the quantitative real-time PCR (qPCR) method with the Relative Expression Software Tool (REST). We found that the HOXD10 expression level was significantly different between cancerous and normal tissues. Downregulation of the HOXD10 gene expression was examined in high-grade samples. Low-grade tissue showed no difference from the control group. HOXD10 expression was reduced in grade II breast carcinoma tissues. This data reveal that misexpression of the HOXD10 gene supports the development and involvement in breast cancer and may serve as a potential biomarker for the diagnosis of human ductal invasive breast carcinoma.