Relationship between MNC OCT-1 activity, CD34⁺ OCT-1 activity and achievement of major molecular response. (A) MNC OCT-1 activity and CD34⁺ OCT-1 activity was measured in 34 CP-CML patients. In these matched samples no correlation was observed between MNC OCT-1 activity and CD34⁺ OCT-1 activity. The Pearson Product Moment was used to assess the correlation. (B) Patients were divided into high and low MNC OCT-1 activity groups (∼ 7.2 ng/200 000 cells¹³ ). Their corresponding CD34⁺ OCT-1 Activities were compared. No difference in CD34⁺ OCT-1 activity was seen between the 2 groups. The median CD34⁺ OCT-1 activity in the low MNC group was 4.38 ng/200 000 cells and the median CD34⁺ OCT-1 activity in the high MNC group was 3.0 ng/200 000 cells. Therefore, a high MNC OCT-1 activity is not indicative of whether a patient will have a high CD34⁺ OCT-1 activity. P values were calculated using the Student t test. (C) Patients were grouped according to the achievement of MMR by 12 months of imatinib treatment and the MNC OCT-1 activity was compared between the 2 groups. The median MNC OCT-1 activity in patients who achieved MMR was 5.64 ng/200 000 cells, whereas for patients who did not achieve MMR the median MNC OCT-1 activity was significantly lower at 2.05 ng/200 000 cells. P values were calculated using the Mann-Whitney Rank Sum. (D) Patients were grouped according to the achievement of MMR by 12 months of imatinib treatment and the CD34⁺ OCT-1 activity was compared between the 2 groups. There was no significant difference in the CD34⁺ OCT-1 activity between patients who did and did not achieve MMR. The median CD34⁺ OCT-1 activity in patients who achieved MMR was 3.36 ng/200 000 cells and the median CD34+ OCT-1 activity in patients who did not achieve MMR was 4.62 ng/200 000 cells. P values were calculated using the Student t test.