Expression of COX-2 protein in different breast cancer cell lines. (Hs578T, MCF-7 and MDA-231). Protein was extracted with RIPA buffer and the expression of COX-2 protein detected by immunoblotting and then quantitated by densitometry. Quantitated data were normalized to GAPDH. The relative units (RU) and ratio for the COX-2 and GAPDH bands for the different breast cancer cell lines were as follows: Hs578T (COX-2-57878/GAPDH-80182) = 0.7218, MCF-7 (COX-2-5871/GAPDH-74734) = 0.05, MDA-231 (COX-2-43861/GAPDH-61470) = 0.7135. Data for invasive cells lines were compared to poorly invasive cell line by one-way ANOVA followed by Student-Newman-Keuls test (,**p < 0.01).