In order to investigate whether the expression levels of HAS2, USP17 and USP4 are correlated, we investigated their expressions in normal human lung fibroblasts and breast epithelial cells (MCF10A), as well as in breast cancer (MCF7, HS578T, MDA-MB-231-BM) and lung cancer (H1299 and A549) cells by immunoblotting. The gene discussed is USP4; the disease is breast carcinoma.