Effects of oxaliplatin (OXA) and 5-fluorouracil+leucovorin (FUL) on the HT-29 cells. Cells were treated with OXA on day 1 before exposure to FUL or on day 2 after 24 h exposure to FUL. Treatment conditions are described in "Material and Methods". On day 3, cells were counted by trypan blue exclusion and CEA expression was measured by FACS analysis by using COL-1 mAb. Columns, total number of cells. Bars, SE of triplicate determinations. No significant difference was observed between the effects of FUL-OXA2 versus OXA1-FUL (p > 0.05). The percentage of the CEA-positive cells was as followed: 14.9 (untreated control); 30.1(FUL); 19.9 (OXA2); 26.2 (FUL-OXA2); 19.1 (OXA1); 21.4 (OXA1-FUL). 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.