Long-term prognostic significance of early molecular response to imatinib in newly diagnosed chronic myeloid leukemia: an analysis from the International Randomized Study of Interferon and STI571 (IRIS).

This study examines the prognostic significance of early molecular response using an expanded dataset in chronic myeloid leukemia patients enrolled in the International Randomized Study of Interferon and STI571 (IRIS). Serial molecular studies demonstrate decreases in BCR-ABL transcripts over time. Analyses of event-free survival (EFS) and time to progression to accelerated phase/blast crisis (AP/BC) at 7 years were based on molecular responses using the international scale (IS) at 6-, 12-, and 18-month landmarks. Patients with BCR-ABL transcripts > 10% at 6 months and > 1% at 12 months had inferior EFS and higher rate of progression to AP/BC compared with all other molecular response groups. Conversely, patients who achieved major molecular response [MMR: BCR-ABL (IS) ≤ 0.1%] by 18 months enjoyed remarkably durable responses, with no progression to AP/BC and 95% EFS at 7 years. The probability of loss of complete cytogenetic response by 7 years was only 3% for patients in MMR at 18 months versus 26% for patients with complete cytogenetic response but not MMR (P < .001). This study shows a strong association between the degree to which BCR-ABL transcript numbers are reduced by therapy and long-term clinical outcome, supporting the use of time-dependent molecular measures to determine optimal response to therapy. This study is registered at www.clinicaltrials.gov as NCT00006343.

High prevalence of hemoglobin disorders and glucose-6-phosphate dehydrogenase (G6PD) deficiency in the Republic of Guinea (West Africa).

Reliable and accurate epidemiological data is a prerequisite for a cost effective screening program for inherited disorders, which however, is lacking in a number of developing countries. Here we report the first detailed population study in the Republic of Guinea, a sub-Saharan West African country, designed to assess the frequency of glucose-6-phosphate dehydrogenase (G6PD) deficiency and hemoglobinopathies, including screening for thalassemia. Peripheral blood samples from 187 Guinean adults were screened for hemoglobin (Hb) variants by standard hematological methods. One hundred and ten samples from males were screened for G6PD deficiency by the fluorescent spot test. Molecular analysis was performed for the most common α-thalassemia (α-thal) deletions, ß-globin gene mutations, G6PD variants B (376A), A (376G), A- (376G/202A) and Betica (376G/968C), using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) or sequencing. Of the 187 subjects screened, 36 were heterozygous for Hb S [ß6(A3)Glu→Val, GAG>GTG] (allele frequency 9.62%). Sixty-four subjects were heterozygous and seven were homozygous for the -α(3.7) kb deletion (allele frequency 20.85%). ß-Thalassemia alleles were detected in five subjects, four with the -29 (A>G) mutation (allele frequency 1.07%) and one with codon 15 (TGG>TAG) (allele frequency 0.96%). The G6PD A- and G6PD Betica deficient variants were highly prevalent with a frequency of 5.7 and 3.3%, respectively. While we did not test for ferritin levels or α(0)-thal, four females (5.2%) had red cell indices strongly suggestive of iron deficient anemia: Hb <9.7 g/dL; MCH <19.3 pg; MCV <68.2; MCHC <31.6 g/dl; RDW >19.8%. Our results are consistent with high frequency of alleles such as Hb S, α-thal and G6PD deficient alleles associated with malaria resistance. Finding a 9.6% Hb S allele frequency supports the notion for a proficient neonatal screening to identify the sickle cell patients, who might benefit from early prophylactic treatment for infections. The incidence of significant iron deficient anemia in women is lower than expected in an under developed country.

European LeukemiaNet criteria for failure or suboptimal response reliably identify patients with CML in early chronic phase treated with imatinib whose eventual outcome is poor.

The majority of patients with chronic myeloid leukemia in chronic phase gain substantial benefit from imatinib but some fail to respond or lose their initial response. In 2006, the European LeukemiaNet published recommendations designed to help identify patients responding poorly to imatinib. Patients were evaluated at 3, 6, 12, and 18 months and some were classified as "failure" or "suboptimal responders." We analyzed outcomes for 224 patients with chronic myeloid leukemia in chronic phase treated in a single institution to validate these recommendations. Patients were followed for a median of 46.1 months. At each time point, patients classified as "failure" showed significantly worse survival, progression-free survival, and cytogenetic response than other patients; for example, based on the assessment at 12 months, the 5-year survival was 87.1% versus 95.1% (P = .02), progression-free survival 76.% versus 90% (P = .002), and complete cytogenetic response rate 26.7% versus 94.1% (P < .001). Similarly, the criteria for "suboptimal response" at 6 and 12 months identified patients destined to fare badly, although criteria at 18 months were less useful. The predictive value of some other individual criteria varied. In general, the LeukemiaNet criteria have useful predictive value, but a case could now be made for combining the categories "failure" and "suboptimal response."

How and why minimal residual disease studies are necessary in leukemia: a review from WP10 and WP12 of the European LeukaemiaNet.

Resistance to therapeutic agents is a major factor in the failure of cancer treatments. In leukemia, the resistant cells remaining in the bone marrow and/or peripheral blood constitute minimal residual disease and are detectable by highly sensitive assays when the patient appears to be in complete remission. Early detection of the expansion of residual cells permits clinical intervention with the aim of reversing the proliferation of resistant leukemic cells. Therefore, accurate and precise measurement of minimal residual disease can greatly enhance optimization of oncology patients' clinical management. This notion is supported by a large body of data among chronic myeloid leukemia patients, but minimal residual disease detection and monitoring is increasingly applied to other types of leukemia, and is starting to be a factor in decision-making for some therapeutic trials in childhood acute lymphoblastic leukemia. Here, from the solid ground of minimal residual disease detection in chronic myeloid leukemia, the current state of the art and development of molecular techniques in other leukemias and the growing field of multiparameter flow cytometry are reviewed in two separate parts reporting on the respective advances, advantages and pitfalls of these emerging methods.

BCL-6: rearrangement and mutation in lymphoma.

BCL-6 is a zinc finger transcription factor that is highly expressed in normal germinal center B-cells. Its function is to prevent differentiation and apoptosis and allow growth. BCL-6 also is expressed in various lymphoproliferative conditions, for example, diffuse large cell lymphoma, Burkitt's lymphoma, and follicular lymphoma as well as lymphocyte predominant Hodgkin's disease. Expression also has been demonstrated in some T-cell lymphomas. In diffuse large cell lymphoma, BCL-6 is involved in translocations with a number of different translocation partners but most commonly the immunoglobulin heavy chain locus. The first intron of BCL-6 is heavily mutated, and detailed analysis reveals two "hotspots." The mutated region appears to be within a transcriptional control region, and there is the potential for alterations to contribute to overexpression of BCL-6. Methods for deoxyribonucleic acid extraction from lymphoma samples and amplification by polymerase chain reaction of the hypermutated intronic region are described.

In vivo kinetics of kinase domain mutations in CML patients treated with dasatinib after failing imatinib.

We sought kinase domain (KD) mutations at the start of treatment with dasatinib in 46 chronic myeloid leukemia (CML) patients resistant to or intolerant of imatinib. We identified BCR-ABL mutant subclones in 12 (26%) cases and used pyrosequencing to estimate subsequent changes in their relative size after starting dasatinib. Four patients lost their mutations, which remained undetectable, 3 patients retained the original mutation or lost it only transiently, 3 lost their original mutations but acquired a new mutation (F317L), and 2 developed another mutation (T315I) in addition to the original mutation within the same subclone. This study shows that expansion of a mutant Ph-positive clone that responds initially to a second generation tyrosine kinase inhibitor may be due either to late acquisition of a second mutation in the originally mutated clone, such as the T315I, or to acquisition of a completely new mutant clone, such as F317L.

Phase I/II trial of adding semisynthetic homoharringtonine in chronic myeloid leukemia patients who have achieved partial or complete cytogenetic response on imatinib.

BACKGROUND: A Phase I/II study was designed to show whether the addition of semisynthetic homoharringtonine (sHHT) would reduce the level of residual disease in patients with Ph-positive chronic myeloid leukemia who appeared to have achieved a suboptimal response to imatinib alone. METHODS: Patients with CML who had achieved >/= 35% Ph-negativity on imatinib were included. All patients had been treated with imatinib at >/= 400 mg/day for at least 2 years and had achieved a plateau in BCR-ABL transcripts defined by measuring BCR-ABL transcripts on at least 4 occasions over a minimum period of 1 year with the latest value not lower than the previous minimum value. Initially sHHT was given subcutaneously at a dose of 1.25 mg/m(2) twice daily for 1 day. Courses were repeated every 28 days. The dosage of sHHT was escalated by adding one day of treatment every two days. Efficacy was assessed by serial monitoring of blood levels of BCR-ABL transcripts. RESULTS: Of 10 evaluable patients, 7 had an appreciable decline in BCR-ABL transcript levels; in 5 cases the reduction was greater than 1 log. Asthenia (n = 10) and cytopenias (n = 3) were prominent side-effects, but the drug was generally well tolerated. Mutations in the P-loop of the BCR-ABL kinase domain were found in 2 of the patients who responded to the addition of sHHT. CONCLUSIONS: The addition of sHHT should be considered for patients on imatinib who fail to obtain low levels of minimal residual disease.

Unusual case of leukemic mantle cell lymphoma with amplified CCND1/IGH fusion gene.

We describe a case of leukemic mantle cell lymphoma (MCL) with complex karyotype and amplification of the CCND1/IGH fusion gene. Testing for the presence of t(11;14), the hallmark of MCL, revealed multiple copies of the fusion signals. We therefore conducted extensive molecular cytogenetic studies to delineate the nature and consequences of such an abnormality. We localized the amplification to the der(14)t(11;14) and to a der(2) chromosome in a form of interspersed chromosome 11 and 14 material. This resulted in high expression of cyclin D1 mRNA and the protein expressed independently of the cell cycle phase. CGH analysis revealed that the overrepresentation on chromosome 11 included chromosomal band 11q23 in addition to the CCND1 locus at 11q13. The band 11q23 harbors the ataxia telangiectasia mutated (ATM) gene recently proposed to be involved in the pathogenesis of MCL with high incidence of deletions in this locus. Using YAC 801e11, containing the ATM gene, we demonstrated several hybridization signals, suggesting that this region also formed part of the amplicon. This case also showed TP53 gene abnormalities: protein expression, monoallelic deletion, and a mutation in exon 5. The clinical course was aggressive, and the patient died within 6 months of presentation. This is to our knowledge the first description of amplification of the CCND1/IGH fusion gene in a human neoplasm, which may have played a role in the fulminating course of the disease in this patient.