Acute myelogenous leukemia switch lineage upon relapse to acute lymphoblastic leukemia: a case report

Acute leukemia, the most common form of cancer in children, accounts for approximately 30% of all childhood malignancies, with acute lymphoblastic leukemia being five times more frequent than acute myeloid leukemia. Lineage switch is the term that has been used to describe the phenomenon of acute leukemias that meet the standard French-American-British system criteria for a particular lineage (either lymphoid or myeloid) upon initial diagnosis, but meet the criteria for the opposite lineage at relapse. Many reports have documented conversions of acute lymphoblastic leukemia to acute myeloid leukemia

Species-Specific Therapy of Acute Lymphoid Leukemia

Forty years ago, Farber and associates described temporary remissions of acute leukemia in children produced by folic acid antagonists [13]. This ignited the hope that this most frequent and always fatal childhood cancer might be curable by drugs. Twenty years ago, Aur and as-sociates completed accession of patients to total therapy study V, the first treat-ment protocol to result in 50 % cure of acute lymphoid leukemia (ALL) [3]. Their results stand 20 years later (Fig. 1), and have been reproduced throughout the world in many thousands of children [6]. More important, recent national vital statistics of the United States and the United Kingdom indicate a 50 % reduc-tion in childhood leukemia mortality [4, 29]. Further, the cured children generally enjoy a normal life-style without need for medication. In the past 20 years, efforts have been directed at improving the cure rate of ALL while simplifying curative treat-ment, reducing its side effects, and im-proving its availability and accessibility. In a Stohlman Lecture at Wilsede 10 years ago the following statement was made [32]:- The most significant opportunity for improving the treatment of acute lymphoid leukemia in the past five years has been its biological and clini-cal classification by immunological cell surface markers. This allows spe-cies identification of the leukemia cells, the first step toward developing specific cytocidal or cytostatic therapy