Prognostic variables in newly diagnosed children and adolescents with acute myeloid leukemia: Children's Cancer Group Study 213.

The objective of this study was to identify biologic parameters that were associated with either exceptionally good or poor outcome in childhood acute myeloid leukemia (AML). Among the children with AML who entered Children's Cancer Group trial 213, 498 patients without Down syndrome or acute promyelocytic leukemia (APL) comprise the basis for this report. Univariate comparisons of the proportion of patients attaining complete remission after induction (CR) indicate that, at diagnosis, male gender, low platelet count (< or =20 000/microl), hepatomegaly, myelodysplastic syndrome (MDS), French-American- British (FAB) category M5, high (>15%) bone marrow (BM) blasts on day 14 of the first course of induction, and +8 are associated with lower CR rates, while abnormal 16 is associated with a higher CR rate. Multivariate analysis suggests high platelet count at diagnosis (>20 000/microl), absence of hepatomegaly, < or =15% day 14 BM blast percentage, and abnormal 16 are independent prognostic factors associated with better CR. Univariate analysis demonstrated a significant favorable relationship between platelet count at diagnosis (>20 000/microl), absence of hepatomegaly, low percentage of BM blasts (< or =15%), and abnormal 16 with overall survival. Absence of hepatomegaly, < or =15% day 14 BM blast percentage, and abnormal 16 were determined to be independent prognostic factors associated with better survival.

Congenital and neonatal leukemia.

Congenital and neonatal leukemia occur rarely, yet carry high mortality rates and pose special problems for the perinatologist and hematologist. Although the etiology is unknown, the presence of leukemia at birth suggests genetic abnormalities and possibly intrauterine exposures to drugs or other toxins as contributing factors. Specific chromosomal rearrangements that are common in congenital leukemia have recently been identified and promise to enhance our understanding of these enigmatic diseases. The differential diagnosis is broad and includes many disorders that occur frequently in the neonatal period. Infants diagnosed with congenital or neonatal leukemia require thorough investigative workup and extensive supportive care. Although the prognosis is poor, recent use of high-intensity multiagent chemotherapy regimens has produced promising results.

Karyotype studies in 18 ependymomas with literature review of 107 cases.

Cytogenetic studies from 17 pediatric ependymomas and 1 ependymoblastoma are presented. Eight tumors had abnormal karyotypes. Another 107 published cases of cytogenetic analyses from pediatric and adult ependymomas or ependymoblastomas were reviewed. Of the total 125 tumors, 83 (66%) had abnormal karyotypes, of which 24 had a sole autosomal abnormality. Approximately one third had monosomy 22 (-22) or breakpoint 22q11-13, with a higher incidence in adult (56%) versus pediatric (28%) tumors. Structural abnormalities of chromosomes 1, 6, and 17, and numerical abnormalities of 7, 9, 12, and 20, in particular, are also discussed. Although no primary cytogenetic abnormality is evident, these findings may provide direction for additional investigations regarding the classification of these tumors.

Family history of cancer and autoimmune disease and risk of leukemia in infancy: a report from the Children's Cancer Group (United States and Canada).

OBJECTIVES: As there are some suggestions that a family history of cancer or autoimmune disease might be associated with an increased risk of leukemia in children, we explored this possibility using data from a matched case-control study conducted by the Children's Cancer Group. METHODS: We compared the family history of cancer and autoimmune diseases of 302 infant leukemia cases (diagnosed within the first 18 months of life) with that of 668 individually matched controls in the United States and Canada. RESULTS: Although not significant, cancer history in parents was found to be associated with an elevated risk of infant leukemia (odds ratio [OR] = 1.4, 95 percent confidence interval [CI] = 0.6-3.6), predominantly acute myeloid leukemia (AML) (OR = 2.2, CI = 0.6-9.0). Cancer history among second-degree relatives was also related to a nonsignificantly elevated risk of AML. Family history of autoimmune diseases, on the other hand, was generally not found to be related to the risk of infant leukemia. CONCLUSION: This study provided no strong evidence that family history of cancer or autoimmune disease is a major risk factor for infant leukemia.

Evaluating the relationships among maternal reproductive history, birth characteristics, and infant leukemia: a report from the Children's Cancer Group.

PURPOSE: Specific events in the mother's reproductive history and certain birth characteristics have been associated with childhood leukemia. Few studies have explored these associations specifically in infants. METHODS: The Children's Cancer Group (CCG) conducted three separate case-control studies of childhood leukemia that involved similar methodologies and data collection. Data from interviews of the mothers of a total of 303 children diagnosed with leukemia at 1 year of age or younger and their matched controls (n = 468) were available from the three studies. These data included maternal reproductive history (stillbirths, abortions, and miscarriages) and certain birth characteristics of the index child. RESULTS: Compared with controls, cases were significantly more likely to be female (P < 0.01) and were more often heavier at birth (particularly cases diagnosed after 6 months of age (odds ratio, 4.18; 95% confidence interval, 1.75-10.02)). Overall, there were no statistically significant differences between cases and controls in regard to maternal report of any type of previous fetal loss. Finally, being a later-born child was associated with an increased risk of acute myeloid leukemia but not of acute lymphoblastic leukemia. CONCLUSIONS: The relationships among birthweight, prior fetal loss, and risk of infant leukemia appear to be complex. Further studies of infant leukemia that incorporate molecular as well as epidemiologic data may help to elucidate these differences.

Chromosome analyses in a rhabdoid tumor of the brain.

A malignant rhabdoid tumor of the brain from a 19-month-old child was studied. Two related clones, 46,XX,-8,+der(8)t(8;22)(p11;q?12)x2,-22,del(22)(q12q?13) and 46,XX-8,+der(8)t(8;22) (p11;q?12) x2,-22,r(22) were found after chromosome analyses of primary and recurrent tumor, and multiple nude mouse passages of the tumor. Breakpoints were studied using FISH.

The human homologue of rat NG2, a chondroitin sulfate proteoglycan, is not expressed on the cell surface of normal hematopoietic cells but is expressed by acute myeloid leukemia blasts from poor-prognosis patients with abnormalities of chromosome band 11q23.

In our efforts to produce monoclonal antibodies that recognize cell-surface antigens expressed by hematopoietic precursor and stromal cells, we generated a monoclonal antibody, 7.1, which recognizes a 220- to 240-kD cell-surface protein whose N-terminal amino acid sequence is identical to the rat NG2 chondroitin sulfate proteoglycan molecule. This chondroitin sulfate proteoglycan, previously reported to be expressed by human melanoma cells, was not found to be expressed by normal hematopoietic cells, nor was it expressed on the cell surface of cell lines of hematopoietic origin including cell lines with 11q23 abnormalities. It was found on the cell surface of acute myeloid leukemia (AML) blasts and cell lines derived from nonhematopoietic tissues. Samples of leukemic marrow from 166 children with AML enrolled on Childrens Cancer Group protocol 213 were evaluated for cell-surface expression of this proteoglycan molecule. In 18 of 166 (11%) patient samples, greater than 25% of leukemic blasts expressed the NG2 molecule. These 18 patients had a poorer outcome with respect to survival (P = .002) and event-free survival (P = .035) with an actuarial survival at 4 years of 16.7%. Blast cell expression of the NG2 molecule was strongly associated with French-American-British M5 morphology (P < .0001) and abnormalities in chromosome band 11q23, site of the MLL gene. These results show that the NG2 molecule is expressed by malignant hematopoietic cells that have abnormalities in chromosome band 11q23, suggesting that antibody 7.1 may be useful in the rapid identification of this group of poor-prognosis patients.

Alterations of the p15, p16,and p18 genes in osteosarcoma.

Activation of cyclin-dependent kinases (CDKs) by interaction with cyclins regulates progression through cell cycle checkpoints. This process is counterbalanced by CDK inhibitors (CDKIs), which can inhibit progression through the cell cycle. Because CDKI expression acts to inhibit cellular proliferation, CDKIs may have a role as tumor suppressors. One class of CDKIs, characterized by the presence of ankyrin repeats, has at least four members (p15INK4B), p16INK4, p18, and p19). Two of these, p15INK4B, p16INK4, have been mapped to chromosome 9p21, a region of frequent loss in a wide variety of cancers. Alterations of p16INK4 have been detected in various tumors and cell lines. We analyzed p15INK4B, p16INK4, and p18 alterations in 52 osteosarcomas (including 11 explants), and 23 other various sarcomas. Single-stranded conformation polymorphism analysis [polymerase chain reaction (PCR-SSCP)] of the coding regions of these CDKI genes detected a missense mutation of p16INK4 exon 1 in one soft tissue sarcoma. Southern blotting detected complete deletion of p15INK4B and p16INK4 genes in osteosarcomas from 2 patients and a soft tissue sarcoma from another individual. Loss of heterozygosity (LOH) at chromosome 9p21 was observed with a microsatellite probe closely linked to the INK4 genes in the latter case. Deletions of both p15INK4B and p16INK4 genes were detected in five of eight osteosarcoma cell lines. By contrast, no alterations of p18 were detected in any sample. Together these data suggest that alterations of the p15INK4B and p16INK4 genes, but not p18, may occur in approximately 5% of sarcomas. However, deletions of the p15INK4B and P16INK4 genes are frequent in osteosarcoma cell lines and probably have a role in tumor cell growth in culture. Notably, all seven detectable deletions involved both p15INK4B and p16INK4 genes, suggesting that both contribute individual tumor suppressor activity.

Alterations of the p53, Rb and MDM2 genes in osteosarcoma.

Molecular defects affecting tumor-suppressor genes are an important step in the genesis of sarcomas. For example, inheritance of a defective Rb or p53 gene predisposes the carrier to develop osteosarcoma, among other malignancies. In this study, we have assessed the occurrence of p53, Rb and MDM2 alterations in the same samples of osteosarcomas, along with representative samples of various other sarcomas. Point mutations of the p53 gene were found in 13 of 42 osteosarcomas and 1 of 8 leiomyosarcomas, and gross rearrangement of the p53 gene was demonstrated in 5 of 37 osteosarcomas. The retinoblastoma susceptibility gene (Rb) was either rearranged or deleted in 7 of 37 osteosarcomas, 1 of 7 soft-tissue sarcomas and 1 of 4 Ewing sarcomas. Remarkably, 5 of the osteosarcomas having Rb alterations also had p53 mutations. Amplification and overexpression of the MDM2 oncogene may lead to increased MDM2-p53 binding resulting in inactivation of p53 function. A two- to threefold increase in the copy number of MDM2 was detected in 7 of 37 samples, 5 of which were osteosarcomas. Amplification of the MDM2 gene occurred independently of p53 mutation; one sample having threefold amplification of MDM2 also had a p53 mutation. In summary, 34 alterations of the p53, Rb and MDM2 genes were found in 26 of 42 (62%) osteosarcomas.

Parental alcohol consumption, cigarette smoking, and risk of infant leukemia: a Childrens Cancer Group study.

BACKGROUND: Whether parental drinking and smoking during pregnancy are associated with an increased risk of cancer in offspring is controversial. There are some indications that maternal alcohol consumption is associated with an elevated risk of acute myeloid leukemia (AML) appearing in very young children. Evidence for an association between maternal smoking during pregnancy and risk of leukemia in offspring has been inconsistent. PURPOSE: Using data from a Children's Cancer Group case-control study, we evaluated relationships between infant leukemia risk and parental alcohol consumption and/or cigarette smoking during pregnancy or during the month prior to it. METHODS: Three hundred two leukemia cases (203 acute lymphoid leukemias [ALLs], 88 AMLs, and 11 other leukemia types) diagnosed in children at 18 months of age or younger and 558 individually matched, regional (i.e., same telephone area code and exchange number) controls were included in the analysis. Information concerning parental alcohol consumption and smoking behavior during the index pregnancy and during the month prior to it was collected by telephone interviews with the mothers of all case and control subjects and the fathers of 250 case and 361 control subjects. Odds ratios (ORs) were used to measure the risk of infant leukemia associated with parental smoking and drinking; tests for trend were used to assess dose-response relationships. The data were analyzed further after stratifying the leukemia cases according to histologic and morphologic types. Reported P values are from two-sided tests of statistical significance. RESULTS: Maternal drinking during pregnancy (compared with not drinking) was associated with ORs of 1.43 (95%) confidence interval [CI] = 1.00-2.04) for ALL and 2.64 (95% CI = 1.36-5.06) for AML. A dose-response relationship was observed for total maternal alcohol consumption during pregnancy and risk of AML (P < .01). Alcohol-related risk appeared to be most pronounced for children who developed AML with a morphology of M1 (myeloblastic with minimal maturation) or M2 (myeloblastic with maturation (OR = 7.62; 95% CI = 2.03-28.64). Paternal alcohol consumption did not confer an increased risk of infant leukemia. Maternal smoking during pregnancy (compared with not smoking) was negatively associated with infant leukemia risk (OR = 0.66 and 95% CI = 0.46-0.94 for total leukemia; OR = 0.45 and 95% CI = 0.21-0.96 for AML), whereas paternal smoking 1 month prior to pregnancy (compared with not smoking during the same period) was related to an elevated risk of ALL (OR = 1.56; 95% CI = 1.03-2.36). CONCLUSIONS: Maternal alcohol consumption during pregnancy increases the risk of infant leukemia, especially AML. Maternal smoking, however, does not elevate risk for either AML or ALL. IMPLICATIONS: The data suggest that in utero exposure to alcohol may contribute to leukemogenesis involving myeloid cells.

Association of paternal diagnostic X-ray exposure with risk of infant leukemia. Investigators of the Childrens Cancer Group.

Whether low level radiation exposure before conception increases the risk of leukemia in offspring has been much debated. No study has specifically evaluated the effect of parental preconception diagnostic X-ray exposure in the development of leukemia among infants. Mothers of 302 infant leukemia cases (diagnosed at < or = 18 months of age) and 558 individually matched regional controls, and fathers of 250 cases and 361 controls, were independently interviewed to obtain information on X-ray exposures. Paternal preconception X-ray exposure was associated with an increased risk of infant leukemia, higher risks being linked to exposures closer to conception. X-ray related leukemia risk varied with exposure site and histopathological type, the highest risk being for acute lymphocytic leukemia related to two or more X-rays of the lower gastrointestinal (GI) tract and lower abdomen (odds ratio, 3.78; 95% confidence interval, 1.49-9.64). A positive association was observed between acute lymphocytic leukemia and number of paternal X-rays of the lower GI and lower abdomen (trend test, P < 0.01), upper GI (P = 0.04), and chest (P = 0.08). Exposures of head and neck and limbs were unrelated to risk. The risk of acute myelogenous leukemia was unrelated to paternal X-ray exposure, except for a marginally significant association (trend test, P = 0.07) for upper GI X-rays. No consistent association between maternal X-ray exposure and infant leukemia was observed. The results of this study suggest that paternal low level radiation exposure before conception is associated with an increased risk of infant leukemia, although the nature of this association needs to be further evaluated.

Cell surface expression of c-kit receptors by childhood acute myeloid leukemia blasts is not of prognostic value: a report from the Childrens Cancer Group.

The prognostic significance of c-kit receptor expression on leukemic blast cells was determined in 122 children with acute myeloid leukemia (AML) entered onto Childrens Cancer Group protocol 213. Clinical and laboratory characteristics as well as outcome were analyzed according to the percentage of blast cells expressing c-kit receptors and the relative number of c-kit receptors per cell as determined by indirect immunofluorescence. c-kit receptor expression was strongly associated with the expression of the CD34 antigen. However, contrary to findings in adult patients with AML, c-kit receptor expression by childhood AML blast cells was not predictive of a poor response to therapy.

Detection of unexpected clones of monosomy 7 in childhood acute lymphoblastic leukemia using fluorescence in situ hybridization.

The feasibility of a fluorescence in situ hybridization (FISH) technique for the detection of leukemic clones with masked chromosomal aberration in interphase nuclei was tested in childhood acute lymphoblastic leukemia (ALL). Twenty-one cases of ALL previously studied by classical metaphase cytogenetics were retrospectively analysed using a centromere-specific chromosome 7 probe. Five cases with karyotypic abnormalities of chromosome 7 (2 with trisomy 7, 2 with monosomy 7 and 1 with trisomy & tetrasomy 7) showed a correlation with FISH results, whereas in five other cases monosomy 7 was found in 12-43% of cells only by FISH. The unexpected detection of monosomy 7 in these latter ALL patients suggests that either these clones are quiescent or unable to enter mitosis in vitro. This suggests that FISH and metaphase cytogenetics must be combined whenever possible to obtain comprehensive karyotypic information.

The study of acute leukemia cells by means of acridine orange staining and flow cytometry.

The studies described here explored the staining of acute leukemia cells with acridine orange (AO). The red fluorescence curve of AML specimens was usually bimodal, suggesting the presence of subpopulations of cells which have different RNA contents. In almost every AML specimen, small leukemic blast cells comprised at least part of the "low RNA content" subpopulation. Residual granulocytes and lymphocytes also contributed to this population. Frequently, the green fluorescence, indicative of the binding of AO to DNA, was slightly less in these cells than in the majority of cells present. There was no evidence however, that the leukemia cells with these characteristics represented a G0 or kinetically quiescent population of cells. In ALL specimens, the presence of multiple cytogenetically distinct clones was easily detectable in AO stained specimens. The red fluorescence curve of G0/G1 ALL cells was unimodal.

Chemotherapy for induction of remission of childhood acute myeloid leukemia followed by marrow transplantation or multiagent chemotherapy: a report from the Childrens Cancer Group.

PURPOSE: In an effort to evaluate the usefulness of bone marrow transplantation, the Childrens Cancer Group (CCG) initiated a multiinstitutional study comparing bone marrow transplantation versus chemotherapy after successful induction of remission for previously untreated children and young adults with acute myeloid leukemia. PATIENTS AND METHODS: From 1979 to 1983, 508 patients were entered onto this study and 490 were treated. After induction, patients with an HLA mixed leukocyte culture (MLC)-compatible sibling underwent bone marrow transplantation. Patients not eligible for bone marrow transplantation were eligible for randomization to two chemotherapy maintenance regimens. All patients undergoing bone marrow transplantation were conditioned with cyclophosphamide and total-body irradiation (TBI). Methotrexate was used to prevent or modify graft-versus-host disease (GVHD). RESULTS: Three hundred eighty-one patients achieved bone marrow remission (78%). Eighty-nine patients had an HLA/MLC-compatible sibling donor and were eligible for bone marrow transplantation, and 252 had no match. Comparison of survival estimates for patients eligible for transplantation versus not eligible at 3 years (52% v 41%), 5 years (50% v 36%), and 8 years (47% v 34%) showed a significant difference in favor of bone marrow transplantation (P < .05). Disease-free survival (DFS) demonstrated similar results. Application of a cure model to the results showed a better outcome for those eligible for transplantation (P = .04). Patients randomized between the two chemotherapy regimens did not show any significant difference between those treated with a continuous maintenance versus a cyclic regimen (P = .16). CONCLUSION: Children and young adults who successfully achieved a remission with multiple-agent chemotherapy who had an HLA/MLC-compatible donor and were thus eligible for an allogeneic bone marrow transplant had better survival than those not eligible for transplantation.