Serial cytogenetic and PCR data for the 12 patients who achieved a complete cytogenetic remission on at least one occasion. Solid circles represent Ph-positive metaphases in the bone marrow and open circles represent Ph-negative marrow cytogenetics. The number of Ph-positive metaphases over the total number of metaphases counted is shown below each circle. Corresponding solid or open triangles represent PCR positive or negative testing of peripheral blood (PB) or bone marrow (BM). “cf” signifies bone marrow culture failure.