The Significance of the Philadelphia Chromosome in Acute Lymphoblastic Leukaemia: a Report of Two Cases

Abstract
Two cases of Philadelphia chromosome (Ph1) positive acute lymphoblastic leukemia are reported, both of which lost the Philadelphia chromosome during remission. In one patient remission of the acute lymphoblastic leukemia continued but classical Ph1 positive chronic granulocytic leukemia developed. In the other patient relapse of the acute lymphoblastic leukaemia occurred associated with the return of the Ph1 chromosome. The chromosome aberration probably occurred in a pluripotential stem cell, which in 1 case proliferated along a lymphoid cell line and a myeloid cell line. Both cases responded well to conventional therapy for acute lymphoblastic leukemia.