Dorothy L. Williams

Secondary Acute Myeloid Leukemia in Children Treated for Acute Lymphoid Leukemia

We studied the risk of the development of acute myeloid leukemia (AML) during initial remission in 733 consecutive children with acute lymphoid leukemia (ALL) who were treated with intensive chemotherapy. This complication was identified according to standard morphologic and cytochemical criteria in 13 patients 1.2 to 6 years (median, 3.0) after the diagnosis of ALL. At three years of follow-up, the cumulative risk of secondary AML during the first bone marrow remission was 1.6 percent (95 percent confidence limits, 0.7 and 3.5 percent); at six years, it was 4.7 percent (2 and 10 percent). The development of secondary AML was much more likely among patients with a T-cell than a non-T-cell immunophenotype (cumulative risk, 19.1 percent [6 and 47 percent] at six years). Sequential cytogenetic studies in 10 patients revealed entirely different karyotypes in 9, suggesting the induction of a second neoplasm. In eight of these patients, the blast cells had abnormalities of the 11q23 chromosomal region, which has been associated with malignant transformation of a pluripotential stem cell. There was no evidence of loss of DNA from chromosome 5 or 7, a karyotypic change commonly observed in cases of AML secondary to treatment with alkylating agents, irradiation, or both. We conclude that there is a substantial risk of AML in patients who receive intensive treatment for ALL, especially in those with a T-cell immunophenotype, and that 11q23 chromosomal abnormalities may be important in the pathogenesis of this complication.

Improved outcome in childhood acute lymphoblastic leukaemia with reinforced early treatment and rotational combination chemotherapy

To improve outcome in childhood acute lymphoblastic leukaemia (ALL), a stratified, randomised study of extended intensified chemotherapy was done. 358 evaluable patients received remission reinforcement therapy (teniposide, cytarabine, high-dose methotrexate) added to a four-drug induction regimen. Those achieving complete remission were randomised on the basis of risk group assignment to conventional continuation treatment or to four pairs of drugs rotated weekly or every 6 weeks. All patients received intrathecal chemotherapy; higher-risk patients also received 1800 cGy cranial irradiation after 1 year of remission. Complete remission was induced in 96% of the patients. At median follow-up of 40 (range 19-73) months, 4-year event-free survival (SE) was 73 (4)% overall, 81 (6)% in the lower-risk group (n = 110), and 69 (5)% in the higher-risk group (n = 248). Outcome within risk groups was not significantly affected by the speed of rotation of drug pairs during continuation treatment. Various high-risk subgroups had apparently improved responses to this treatment. This intensified chemotherapy may cure 69-77% of children with ALL.

New chromosomal translocations correlate with specific immunophenotypes of childhood acute lymphoblastic leukemia

Cytogenetic analysis of leukemic cells obtained at diagnosis from 122 patients with childhood acute lymphoblastic leukemia (ALL) disclosed chromosomal translocations in 36 cases. Two new nonrandom translocations were identified and found to be associated with specific immunophenotypes of the disease. The first, identified in 4 of 16 cases of T-cell ALL positive for sheep erythrocyte receptors (E+), involved the short arm (p) of chromosome 11 and the long arm (q) of chromosome 14 and was designated t(11;14) (p13;q13). The second, found in 7 of 23 cases with a pre-B-cell phenotype, involved the long arm of chromosome 1 and the short arm of chromosome 19; it was designated t(1;19) (q23;p13.3). A third abnormality involving a common breakpoint on chromosome 12 (band p 12) was also identified. These two new differentiation-specific translocations suggest a mechanism for aberrant expression of genes that influence lymphoid cell growth and development, as well as leukemogenesis.

A direct bone marrow chromosome technique for acute lymphoblastic leukemia.

We describe a direct bone marrow chromosome technique that was developed especially for use in studies of acute lymphoblastic leukemia (ALL). The features responsible for technical improvements include: the use of RPMI 1640 medium, supplemented with 30% fetal calf serum, to support cellular activity during both specimen transport and Colcemid treatment; the processing of only 0.1 ml of sedimented cells or less per centrifuge tube; the exposure of cells to Colcemid for a maximum of 25 min; control of the total time of exposure to hypotonic solution; the use of a steel wire as a stirring rod (fashioned to fit the centrifuge tube) for mixing cells; slide preparation by a specific edging-flaming technique; the natural aging of the slides to achieve optimal drying; and the use of a modified G-banding procedure that employs Wrights stain. This technique has been used in more than 350 cases of ALL and has consistently provided analyzable banded chromosomes, even in hyperdiploid cases with up to 91 chromosomes. It makes the previously recognized morphological difference between metaphases of residual normal cells and those from the leukemic clone less apparent. The edging-flaming technique of slide preparation is the most important component and is especially appropriate for spreading large numbers of chromosomes in ALL.

Cytogenetics of pre-B-cell acute lymphoblastic leukemia with emphasis on prognostic implications of the t(1;19).

In earlier studies of the cytogenetic characteristics of leukemic lymphoblasts from children with pre-B-cell acute lymphoblastic leukemia (ALL), we concluded that certain chromosomal abnormalities explain, in part, the increased presence of high-risk features at diagnosis and the less favorable response to therapy among patients with this immunologic subclass of ALL. With extended follow-up and a larger patient population, we have further evaluated the biologic and clinical aspects of pre-B leukemia. Of 686 cases of ALL with adequate immunophenotyping, 150 were classified as pre-B cell. Seventy-seven (69%) of the 112 pre-B cases with fully banded karyotypes had a translocation. The t(1;19) accounted for 28 (25%) of these pre-B cases and 31 (6.5%) of all 480 consecutively banded ALL cases. Three (2.6%) of the pre-B cases had a novel dicentric (7;9)(p1?3;p11) translocation. A t(9;22)(q34;q11) and a t(4;11)(q21;q23) were observed in seven (6%) and three (2.6%) of the cases, respectively. Within the pre-B subgroup, comparison of t(1;19) cases (n = 28) with those having other translocations (n = 49) or no identifiable translocations (n = 35) indicated that higher leukocyte counts (P = .002), absence of DNA indexes greater than 1.16 (P = .02), higher serum lactate dehydrogenase levels (P less than .0001), and a higher frequency of nonwhite race (P = .006) were significantly related to the t(1;19). Both the t(1;19) and other chromosomal translocations were associated with an adverse prognosis in the subset of patients treated from 1979 to 1984 (Total Therapy study X). In a more recent and more intensive chemotherapy program (Total Therapy study XI), neither the t(1;19) nor other chromosomal translocations has conferred an inferior outcome, suggesting that effective treatment can offset the negative impact of chromosomal rearrangements in cases of childhood pre-B ALL.

Acute leukaemia with mixed lymphoid and myeloid phenotype.

Summary Three children with acute leukaemia had blasts that expressed both lymphoid and myeloid markers. The blasts met immunological criteria for acute lymphoblastic leukaemia (ALL)—common ALL antigen+, HLA‐DR+, terminal deoxynucleotidyl transferase+–but their cytochemical features, including positive myeloperoxidase and Sudan black B, were those of acute nonlymphoblastic leukaemia (ANLL) as defined by the French‐American‐British Group. 30% of the blasts from one of two patients tested reacted with a monoclonal antibody specific for nonlymphoid cells (MCS‐2). The wide overlap in the percentages of blasts expressing lymphoid or myeloid markers indicates that some leukaemic cells in each child had a mixed phenotype. There were no consistent cytogenetic findings, and the Philadelphia chromosome was not present. Complete remission was induced by treatment effective for either ALL (two patients) or ANLL. These three cases appear to represent a rare leukaemia subtype that we have designated acute leukaemia with mixed lymphoid and myeloid phenotype. Its recognition may be important in treatment, since two patients achieved remission with standard therapy for ALL. These cases demonstrate further the phenotypic heterogeneity that may be seen in leukaemic cell differentiation.

Cytogenetics of childhood acute nonlymphocytic leukemia

Interest in more precise subclassification of the acute leukemias by cytogenetic criteria led us to identify and characterize the full range of chromosomal abnormalities in 121 children with de novo acute nonlymphocytic leukemia (ANLL). Only 21% of the cases had normal karyotypes; 62% had consistent or recurrent alterations, most commonly inv(16) or del(16), t(8;21), t(15;17), t(9;11), t(11;V) or del(11), and -7 or 7q-; and 17% had miscellaneous, apparently random, clonal abnormalities. Statistically significant associations between chromosomal abnormalities and the morphologic/cytochemical subtypes of ANLL, defined by criteria of the French-American-British (FAB) cooperative group were demonstrated for the t(8;21) in M1 and M2 leukemia, t(15;17) in M3, t(9;11) in M5, and translocations involving 11q23 other than t(9;11) [t(11;V)] or del(11q) in M4 and M5. The chromosome 16 inversion was not restricted to the M4 subtype, as is generally reported, and was not uniformly associated with increased and/or abnormal marrow eosinophils. None of these 121 cases were characterized by the Philadelphia chromosome, nor did any have the t(6;9), t(16;16), or inv(3), which have been noted previously in this disease. In addition to confirming several recognized correlations between recurrent structural chromosome abnormalities and FAB subtypes, this study identified novel abnormalities that have not been reported by others. It also disclosed an unusual heterogeneity of chromosome 16 abnormalities with respect to their distribution among FAB subtypes, their association with marrow eosinophilia, and their participation with other chromosomes in translocations.

Prognostic importance of cytogenetic subgroups in de novo pediatric acute nonlymphocytic leukemia.

Reports of close associations between recurring chromosomal abnormalities and the clinical behavior of acute nonlymphocytic leukemia (ANLL) have stimulated efforts to define this disease in cytogenetic terms. Here we report on the leukemic cell karyotypes of 155 children with ANLL who were treated from 1980 to 1987 in consecutive programs of chemotherapy at this institution. Of 121 cases with adequate banding, 20% were normal, 30% had miscellaneous clonal abnormalities, and 50% were classified into known cytogenetic subgroups: inv(16)/del(16q) (n = 15), t(8; 21) (n = 14), t(15;17) (n = 9), t(9;11) (n = 9), t(11;V)/del(11q) (n = 7) and -7/del(7q) (n = 6). The inv(16)/del(16q) cases showed a nearly equal distribution of myelocytic and monocytic French-American-British (FAB) subtypes; only four of these patients presented with M4Eo morphology. Despite a 100% remission induction rate, patients with inv(16)/del(16q)-positive ANLL fared no better overall than the entire group; only 40% of this subgroup were event-free survivors at 2 years from diagnosis (P = .23). Patients with inv(16)/del(16q) frequently had CNS involvement at diagnosis (eight of 15) or initially relapsed in this site (three of eight). Event-free survival (EFS) was clearly superior for young patients with FAB M5 leukemia and the t(9;11) (P = .041). These patients were clinically indistinguishable from others with the FAB disease subtype, yet their responses to etoposide-containing therapies were noteworthy. By contrast, children with structural abnormalities involving 11q23, other than t(9;11), were infants (median age, 6 months) with FAB M4 or M5 leukemia, hyperleukocytosis, and frequent coagulation abnormalities. Patients with such changes [t(11;V) or del(11q)] relapsed early during postremission therapy: none remained disease-free more than 16 months from diagnosis. Because of resistant leukemia, patients with monosomy 7/del(7q) had a poor remission induction rate (17%; P = .0015); patients with the t(15;17) were also poor responders to induction therapy (44%; P = 0.02) because of hemorrhagic deaths. These results identify several cytogenetic subtypes of pediatric ANLL that may represent unique disease processes for which more effective early cytoreduction [-7/del(7q), t(11;V)], better supportive care measures [t(15;17)], or more effective CNS prophylaxis [inv(16)/del(16q)] would be warranted.

Correlation of karyotype and immunophenotype in childhood acute lymphoblastic leukemia.

To correlate leukemic cell karyotype with immunophenotype, we studied 364 children with acute lymphoblastic leukemia (ALL). A prognostically favorable cytogenetic feature, hyperdiploidy greater than 50 chromosomes, was found in 33% of cases classified as common ALL antigen positive (CALLA+) early pre-B (common) ALL, in contrast to 18% of pre-B cases (P = .012), 5% of T cell cases (P less than .001), and none of the B cell cases (P less than .001) or cases of CALLA negative (CALLA-) early pre-B ALL (P = .002). The frequency of translocations, an adverse cytogenetic feature, was significantly lower in CALLA+ early pre-B ALL cases (35%) than in B cell (100%; P less than .0001), pre-B (59%; P less than .001), or CALLA- early pre-B (62%; P = .016) cases. Thus, patterns of chromosomal change differ widely among the major immunophenotypic groups of ALL and may account for reported differences in responsiveness to treatment.

Cytogenetic features of acute nonlymphoblastic leukemia in 73 children and adolescents

We examined the leukemia cells of 81 consecutively admitted children and adolescents with acute nonlymphoblastic leukemia (ANLL) to determine the frequency and specificity of chromosomal abnormalities. Karyotypes were obtained for 73 (90%) of the 81 children, and 36 (49%) were abnormal. The modal karyotypes for the cases were tightly clustered in the diploid range; only 5 (7%) were hypodiploid, with 45 chromosomes each, and only 2 (3%) had greater than 50 chromosomes. Specific chromosomal abnormalities in the abnormal karyotypes were compared to morphologic subgroups of ANLL. An 8;21 translocation was found in 6 of 9 cases with M2 morphology but was also found in 1 case with M1 morphology. One of 4 with M3 (progranulocytic) morphology had a 15;17 translocation, and another had a 17q deletion. A structural abnormality in 11q was found in 3 of 7 patients with M5 (monoblastic) morphology, 2 of whom had a 9;11 translocation. The only case of M6 had a 22q-or Philadelphia chromosome in addition to other abnormalities. Statistical analysis of 27 abnormal karyotypes showed preferential structural rearrangement of 8q and 21q. We conclude that, in children as well as adults, specific structural abnormalities are correlated with certain morphologic subgroups of ANLL. However, other chromosomal changes associated with prior mutagenic exposure of adult ANLL were uncommon in children, which may suggest a difference in pathogenesis.