The p53 gene in pediatric therapy-related leukemia and myelodysplasia.

We investigated the frequency of p53 mutations in 19 pediatric cases of therapy-related leukemia or myelodysplastic syndrome. Eleven children presented with acute myeloid leukemia, one with mixed-lineage leukemia, two with acute lymphoblastic leukemia, and five with myelodysplasia at times ranging from 11 months to 9 years after a primary cancer diagnosis. The primary cancers, which included 11 solid tumors and eight leukemias, were treated with various combinations of DNA topoisomerase II inhibitors, alkylating agents, or irradiation. Leukemic or myelodysplastic marrows were screened for possible mutations by single-strand conformation polymorphism (SSCP) analysis of p53 exons 4 to 8. The only observed mutation was an inherited 2-basepair deletion at codon 209 in exon 6 that would shift the open reading frame, create a premature termination codon, and foreshorten the resultant protein. Prior therapy in this patient included DNA topoisomerase II inhibitors, alkylating agents, and irradiation. The secondary leukemia presented as myelodysplasia with monosomies of chromosomes 5 and 7 and abnormalities of chromosome 17. Although the primary cancer was an embryonal rhabdomyosarcoma and there was a family history of cancer, the case did not fulfill the clinical criteria for Li-Fraumeni syndrome. This study suggests that germline p53 mutations may predispose some children to therapy-related leukemia and myelodysplasia, but that p53 mutations otherwise are infrequent in this setting.

Methotrexate/L-asparaginase combination chemotherapy for patients with acute leukemia in relapse: a study of 36 children.

Cyclic administration of methotrexate (MTX) and L-Asparaginase (L-Asp) was utilized either as induction and maintenance chemotherapy or as maintenance chemotherapy alone following induction with other medications in treating 36 children with multiple relapses of acute leukemia. A complete remission rate (CR) of 67% was obtained in children with null-cell acute lymphocytic leukemia (ALL). The average length of remission was greater than four months. One of three patients with T-cell ALL and one of two patients with B-cell ALL achieved CR. In six cases of acute nonlymphocytic leukemia (ANLL), two patients achieved CR. One of two patients with terminal deoxynucleotidyl transferase (TdT) negative myeloblastic transformation of Ph'-positive chronic myelogenous leukemia (CML) obtained a CR lasting 20 weeks. Toxicity secondary to the chemotherapy included bone marrow suppression, hepatic injury, nausea, diarrhea, stomatitis, and allergic reactions to L-Asp. One case of subacute necrotizing leukoencephalopathy was seen.

Isolated pulmonary leukemic relapse following successful bone marrow transplant in a child with acute lymphoblastic leukemia.

Leukemic relapse and interstitial pneumonitis are common complications for leukemic patients following bone marrow transplantation. We present the case of a successful bone marrow transplantation patient who developed an interstitial infiltrate on chest roentgenogram 212 days post-transplant that was diagnosed by open lung biopsy and found to be a leukemic relapse of the lung parenchyma. No extrapulmonary sites were involved and the infiltrate cleared in three weeks with systemic chemotherapy. Pulmonary function tests continued to demonstrate restrictive disease. The patient remained in remission for nine months following pulmonary relapse on systemic chemotherapy. This patient illustrates an unusual site of leukemic relapse and the importance of open lung biopsy in the diagnosis of the immunosuppressed patient with a pulmonary infiltrate.

Acute myeloblastic leukemia two years after diagnosis of non-Hodgkin lymphoma.

The 18-year-old white male developed acute myeloblastic leukemia (AML) 25 months after diagnosis of poorly differentiated lymphocytic lymphoma, diffuse pattern (PDLL-D), involving cervical, supraclavicular, and mediastinal lymph nodes as well as bone marrow. Treatment of the lymphoma consisted of 2,000 rads to the mantel area and 18 months of chemotherapy with intravenous (IV) methotrexate (400 mg/m2), vincristine, and prednisone, alternating every two weeks with IV cyclophosphamide (1,000 mg/m2), vincristine, and prednisone plus monthly intrathecal methotrexate. Thereafter, a complete remission was maintained without therapy until the onset of AML. Several pseudodiploid clones containing multiple structural rearrangements and a hypodiploid clone were identified in the circulating blood at the time of diagnosis of AML. Induction therapy consisting of cytosine arabinoside, 5-azacytidine, vincristine, and prednisone was unsuccessful, and the patient died of sepsis two months after diagnosis. This case calls attention to the increased risk for subsequent acute nonlymphocytic leukemia in patients previously treated for nonhodgkin lymphoma.