TY - JOUR TI - Evaluation at single cell level of residual Philadelphia negative hemopoietic stem cells in chronic phase CML patients AU - Akel, S AU - Kolialexi, A AU - Mavrou, A AU - Metaxotou, C AU - Loukopoulos, AU - D AU - Yataganas, X JO - CANCER GENETICS AND CYTOGENETICS PY - 2000 VL - 122 TODO - 2 SP - 93-100 PB - EXCERPTA MEDICA INC-ELSEVIER SCIENCE INC SN - 0165-4608 TODO - 10.1016/S0165-4608(00)00280-6 TODO - null TODO - In chronic myeloid leukemia, accurate determination of Ph- Hemopoietic stem cells (HSC) in peripheral blood (PB), bone marrow (BM) and leukapheresis products is important for the selection of patients for whom mobilization, collection, and autografting of Ph- HSC are envisaged. To this effect, the BCR/ABL fusion was assessed at the single cell level in 25 sets of PB and BM samples using dual-color I-FISH in immunophenotyped CD34(+) cells and RT-PCR of individual CFU-GM colonies. In 15 cases found to be 100% Ph+, the respective BCR/ABL gene was absent in 30% of CD34(+) cells, while the respective transcripts could not be identified in 17% of CFU-GM. The mean percentage of BCR/ABL(-) CD34(+) cells and CFU-GM cells was higher (38% and 29%, respectively) in untreated patients than in treated patients (24% and 7%, respectively). In eight cases with cytogenetic response (CgR), the percentage of Ph- metaphases correlated with the level of BCR/ABL(-) colonies in BM and PB and with the proportion of BCR/ABL(-) CD34(+) cells in the BM. Immunophenotyping and FISH was fast, easy, always informative, and quantitative for the BCR/ABL- CD34(+) cells. Our results show that (a) at early diagnosis a high frequency of BCR/ABL(-) HSC circulate in the PB and that Ph- hematopoiesis is not completely suppressed: (b) although normal clonogenic cells decline rapidly within a few months after diagnosis, appreciable numbers of normal CD34(+) cells survive in chronic phase, especially in patients with CgR. (C) 2000 Elsevier Science Inc. All rights reserved. ER -