Western blot (A) and densitometric analysis (B) of CEA expression in HT-29 cells. Following treatment with oxaliplatin (OXA) before or after exposure to 5-fluorouracil + leucovorin (FUL), cells were washed in PBS and the pellet was suspended in extraction buffer. Cell lysates were subjected to SDS-PAGE and immunoblotting was performed with MAb COL-1 for CEA detection. Molecular weights in kDa are placed on the left. See "material and methods" for experimental details. Immunoblot was scanned by densitometer and the optical density was expressed as arbitrary units. OXA2, cells were treated with OXA on day 2; FUL-OXA2, FUL followed by OXA2 treatment; OXA1, cells were treated with OXA on day 1; OXA1-FUL, OXA1 followed by FUL treatment.