Overall survival and relapse-free survival of patients with primary AML in relation to the coexpression of CXCR-4 and CD34. OS (A) and RFS (B) for AML are expressed in relation to the percentages of cells coexpressing CXCR-4 and CD34. Solid lines indicate patients in which less than 1% of all cells coexpressed CXCR-4 and CD34; dotted lines, patients in which 1% or more of cells coexpressed CXCR-4 and CD34. OS (C) and RFS (D) are given in relation to the fraction of CD34⁺ cells expressing CXCR-4. Solid lines indicate patients in which less than 20% of CD34⁺ cells expressed CXCR-4; dotted lines, patients in which 20% or more of the CD34⁺ cells expressed CXCR-4. Crosses refer to censored cases.