Improved prognosis of acute nonlymphocytic leukemia in children: results of the 12th-ANLL protocol of Tokyo Children's Cancer Study Group

Development of acute myeloid leukemia after chemotherapy for osteosarcoma

The current study describes two patients with osteosarcoma who had acute myeloid leukemia develop after treatment with multiagent chemotherapy. The incidence density for the chemotherapy protocol was 129.8 per 10,000 person-year of followup. Karyotype analysis of 16 reported patients (including the current two patients) indicated that most leukemias after treatment of osteosarcoma correlated with the use of topoisomerase II inhibitors, such as doxorubicin. The deoxyribonucleic acid-damaging activity of doxorubicin reinforced by the use of alkylating agents is highly suspected as a causative event in the development of leukemia after treatment of osteosarcoma. As the next step in the development of treatment for patients with osteosarcoma, the type and intensity of treatment must be evaluated to minimize possible leukemogenic effects without compromising the potential for cure.

Acute myeloblastic leukemia associated with trisomy 8 and translocation 8;21 in a child with Down syndrome

The present study examined an 11-year-old girl with Down syndrome who suffered from acute myeloblastic leukemia (AML) preceded by preleukemic pancytopenia. Chromosomal analysis of leukemic cells revealed a chromosome change at t(8;21) and trisomy 8 associated with constitutional trisomy 21. Treatment with antineoplastic agents led to complete remission.

Detection of chimeric mRNAs by reverse transcriptase-polymerase chain reaction for diagnosis and monitoring of acute leukemias with 11q23 abnormalities

Recurrent translocations involving chromosome band 11q23 are often found in human acute leukemias. Recently, the MLL gene on 11q23 and 10 partner genes involved in these translocations have been cloned and characterized. We performed a reverse transcriptase-polymerase chain reaction (RT-PCR) to detect the resultant der(11) chimeric mRNAs of the 3 types of 11q23 translocations including t(4;11), t(9;11), or t(11;19), in 14 leukemia patients with MLL gene rearrangements. At diagnosis or relapse, chimeric mRNA could be detected in all of the 4 patients with t(4;11), 2 of 3 with t(9;11), 2 of 3 with t(11;19), and 1 of 4 with unsuccessful karyotype. In 5 patients, we could monitor minimal residual disease (MRD) serially through the clinical course. One patient, in whom chi-meric mRNA was detected during complete remission (CR) just after the induction chemotherapy, relapsed within 2 months and died, while 2 patients in which chimeric mRNA was not detected remained in CR from 10-23 months. These findings suggest that RT-PCR is a useful approach for detecting which partner gene is involved in the translocation and monitoring MRD in patients with MLL gene rearrangement. Nonetheless, the clinical relevance of MRD evaluation by RT-PCR monitoring remains controversial. Long-term and prospective investigation of a larger series of patients is needed to confirm the clinical significance of monitoring MRD by RT-PCR method.

Chromosome abnormalities and prognosis in childhood acute leukemia

We report here on the leukemic cell karyotypes of 134 children with acute nonlymphocytic leukemia (ANLL) examined at Saitama Children's Medical Center (SCMC), and of 88 children with acute lymphoblastic leukemia (ALL) referred to SCMC. The patients were mainly treated according to the protocol of the Tokyo Children's Cancer Study Group. Of 106 ANLL cases with adequate banding, 18% were normal, 34% had miscellaneous clonal abnormalities, and 48% were classified into known cytogenetic subgroups: t(8;21) (n = 21), 11q23 abnormalities (n = 14), -7/del(7q) (n = 6), inv (16)/del(16) (n = 5), and t(15;17) (n = 5). According to the FAB classification, M7 (21.7%) were more frequent than in previous reports because this study included a number of Down's Syndrome patients with M7 morphology. The present study confirmed the well-known association of t(15;17) with M3, t(8;21) with M2, 11q23 abnormalities with M4 and M5, and inv (16)/del(16) with M4. Patients with t(8;21) or inv (16)/del(16q) ANLL fared no better overall than the entire group. Of 51 ALL cases with adequate banding, 13.7% were normal, and 86.3% were classified into abnormal subgroups: translocation (n = 14), hyperdiploidy (greater than 50) (n = 13), and miscellaneous abnormalities (n = 17). Cases with hyperdiploidy (greater than 50) were restricted to a common phenotype and fared better overall than the entire group. Patients with translocation were found in all phenotypes, and had a poor prognosis. We concluded that childhood acute leukemia could be subgrouped according to karyotypic patterns, and that patients with translocations had a poor prognosis in ALL as well as ANLL.