We previously reported the involvement of zinc-finger protein 143 (ZNF143) on cancer cell motility in colon cancer cells. Here, ZNF143 was further characterized in breast cancer. Immunohistochemistry was used to determine the expression of ZNF143 in normal tissues and in tissues from metastatic breast cancer at various stages. Notably, ZNF143 was selectively expressed in duct and gland epithelium of normal breast tissues, which decreased when the tissue became malignant. To determine the molecular mechanism how ZNF143 affects breast cancer progression, it was knocked down by infecting benign breast cancer cells with shorthairpin (sh) RNA-lentiviral particles against ZNF143 (MCF7 sh-ZNF143). MCF7 sh-ZNF143 cells showed different cell-cell contacts and actin filament (F-actin) structures when compared with MCF7 sh-Control cells. In migration and invasion assays, ZNF143 knockdown induced increased cellular motility in breast carcinoma cells. This was reduced by the recovery of ZNF143 expression. Taken together, these results suggest that ZNF143 expression contributes to breast cancer progression. [BMB Reports 2017; 50(12): 621-627].