Search

Additional chromosome abnormalities (ACAs) occur in less than 10% of cases at diagnosis of Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML). In some cases, on the basis of the persistence of the ACAs in Ph-negative cells after response to imatinib, a secondary origin of the Ph chromosome has been demonstrated. In this study, the possible prognostic value of this phenomenon was evaluated. Thirty-six Ph-positive CML patients were included in the study. In six patients, ACAs persisted after the disappearance of the Ph. A complete cytogenetic response (CCR) was obtained in five of these six patients, and five of six also had a high Sokal score. In all the other cases, ACAs disappeared together (in cases of response to therapy with imatinib) or persisted with the Ph (in cases of no response to imatinib). In the former cases, the primary origin of the Ph was demonstrated. CCR was obtained in 22 cases (17 with low to intermediate Sokal scores), while no response was observed in 8 patients (5 with a high Sokal score). Sokal score seems to maintain its prognostic value for patients in whom the Ph occurs as a primary event, but not in those in whom it occurs as a secondary one.

The Philadelphia chromosome (Ph-chromosome) has long represented the only cytogenetic abnormality known to be associated with a specific malignant disease in humans, being present in more than 95% of patients with chronic myelogenous leukemia. This abnormality is the result of a reciprocal translocation between the long arms of chromosome 9 and 22, t(9;22)(q34;q11), and its presence is not restricted to chronic myelogenous leukemia, but can also be found in 30% of cases of acute lymphoblastic leukemia in adults. In the 1980s, the molecular counterpart of the chromosomal rearrangement was identified to consist of the juxtaposition of parts of the BCR and ABL genes to form a BCR-ABL hybrid gene. The resulting chimeric proteins (P210 and P190), which retain constitutively activated tyrosine kinase activity, have demonstrated a causative role in the genesis of the leukemic process. Although many aspects of the BCR-ABL driven transformation remain unsolved, great advances in understanding the molecular pathology of Ph-positive leukemias resulted in meaningful improvement in the clinical setting. Molecular tools to diagnose disease (PCR, FISH, and southern blot) and to monitor minimal residual disease after potential curative treatment are now in current practice, and new powerful therapeutic tools have emerged that target the molecular oncogenic pathways activated in Ph-positive cells. Among them, specific ABL tyrosine kinase inhibitors recently obtained extraordinary results in many clinical protocols. This review summarizes the most recent advances in this field with special focus on the putative mechanisms of the transformation and progression of chronic myelogenous leukemia and on the major impact that understanding the molecular biology of these diseases is having in clinical practice.

Not available.

Purpose Deletions of the derivative chromosome 9 [der(9)] have been associated with a poor prognosis in chronic myeloid leukemia (CML) across different treatment modalities. In the imatinib era, the prognostic impact of der(9) deletions has been evaluated mainly in patients with late chronic-phase (CP) CML, giving partially conflicting results. Few data are available in the early CP setting. For this reason, in 2006, the European LeukemiaNet recommendations still considered der(9) deletions as a candidate adverse prognostic factor and required a careful monitoring of the patient. Patients and Methods To investigate the prognostic value of der(9) deletions in early CP CML, we performed an analysis of three prospective imatinib trials of the Italian Group for Hematological Malignancies of the Adult (GIMEMA) CML Working Party. Results A fluorescent in situ hybridization (FISH) analysis of bone marrow cells was performed at diagnosis; der(9) deletions were detected in 60 (12%) of 521 evaluable patients. At 60 months, the cumulative incidence of complete cytogenetic response and major molecular response—and the probability of event-free survival, failure-free survival, progression-free survival, and overall survival—in patients with and without deletions were not statistically different. Conclusion Our data strongly support the notion that, when investigated by FISH, der(9) deletions are not a poor prognostic factor in patients with early CP CML treated with imatinib.

In chronic myeloid leukemia, different methods are available to monitor the response to therapy: chromosome banding analysis (CBA), interphase fluorescence in situ hybridization (I-FISH), and real-time quantitative polymerase chain reaction (RT-Q-PCR). The GIMEMA CML WP (Gruppo Italiano Malattie Ematologiche Adulto Chronic Myeloid Leukemia Working Party) has performed a prospective study to compare CBA and I-FISH for the definition of complete cytogenetic response (CCgR). Samples (n = 664) were evaluated simultaneously by CBA and I-FISH. Of 537 cases in CCgR, the number of positive nuclei by I-FISH was less than 1% in 444 cases (82.7%). Of 451 cases with less than 1% positive nuclei by I-FISH, 444 (98.4%) were classified as CCgR by CBA. The major molecular response rate was significantly greater in cases with I-FISH less than 1% than in those with I-FISH 1% to 5% (66.8% vs 51.6%, P < .001) and in cases with CCgR and I-FISH less than 1% than in cases with CCgR and I-FISH 1% to 5% (66.1% vs 49.4%, P = .004). I-FISH is more sensitive than CBA and can be used to monitor CCgR. With appropriate probes, the cutoff value of I-FISH may be established at 1%. These trials are registered at http://www.clinicaltrials.gov as NCT00514488 and NCT00510926.

Since interferon-α and imatinib (IM; STI571, Glivec, Gleevec) are effective for the treatment of chronic myeloid leukemia (CML), and their mechanisms of action are different, we designed an exploratory study investigating the effects of a standard IM dose (400 mg/d) and a variable pegylated interferon-α (PegIFN) dose (50 μg/wk, 100 μg/wk, and 150 μg/wk). The criteria for dose adjustment were designed so as to ensure the delivery of the IM dose and to protect life quality. There were 76 patients with previously untreated Philadelphia (Ph)–positive CML enrolled in the study. There were 3 patients who discontinued IM and 45 patients who discontinued PegIFN. The severity of adverse events increased with increasing PegIFN dose. The IM dose could be administered to the patients who were assigned to receive 50 μg/wk or 100 μg/wk PegIFN but not to those who were assigned to receive 150 μg/wk. The median administered dose of PegIFN ranged between 32 μg/wk and 36 μg/wk. The cytogenetic response was 70% complete (Ph-neg 100%) and 83% major (Ph-neg > 65%). The BCR/ABL transcript was reduced by at least 3 logs in 68% of complete cytogenetic responders. These data of toxicity, compliance, and efficacy may assist in the design and preparation of prospective studies.

We recently described morgana as an essential protein able to regulate centrosome du- plication and genomic stability, by inhibiting ROCK. Here we show that morgana 1/2 mice spontaneously develop a lethal myeloproliferative disease resembling human atypical chronic myeloid leukemia (aCML), preceded by ROCK hyperactivation, centrosome am- plification, and cytogenetic abnormalities in the bone marrow (BM). Moreover, we found that morgana is underexpressed in the BM of patients affected by atypical CML, a disorder of poorly understood molecular basis, characterized by nonrecurrent cytogenetic abnormalities. Morgana is also underexpressed in the BM of a portion of patients affected by Philadelphia-positive CML (Ph1 CML) caused by the BCR-ABL oncogene, and in this condition, morgana underexpression predicts a worse response to imatinib, the standard treatment for Ph1 CML. Thus, morgana acts as an oncosuppressor with different modalities: (1) Morgana underexpression induces centrosome amplifi- cation and cytogenetic abnormalities, and (2) in Ph1 CML, it synergizes with BCR-ABL signaling, reducing the efficacy of imatinib treatment. Importantly, ROCK inhibitionin the BM of patients underexpressing morgana restored the efficacy of imatinib to induce apoptosis, suggesting that ROCK inhibitors, combined with imatinib treatment, can overcome suboptimal responses in patients in which morgana is underex- pressed. Fil: Di Savino, Augusta. Universitã â Di Torino; Italia Fil: Panuzzo, Cristina. Universitã â Di Torino; Italia Fil: Rocca, Stefania. Universitã â Di Torino; Italia Fil: Familiari, Ubaldo. Universitã â Di Torino; Italia Fil: Piazza, Rocco. Universita Degli Studi Di Milano; Italia Fil: Crivellaro, Sabrina. Universitã â Di Torino; Italia Fil: Carrà, Giovanna. Universitã â Di Torino; Italia Fil: Ferretti, Roberta. Universitã â Di Torino; Italia Fil: Fusella, Federica. Universitã â Di Torino; Italia Fil: Giugliano, Emilia. Universitã â Di Torino; Italia Fil: Camporeale, Annalisa. Universitã â Di Torino; Italia Fil: Franco, Irene. Universitã â Di Torino; Italia Fil: Miniscalco, Barbara. Harvard Medical School; Estados Unidos Fil: Cutrin, Juan Carlos. Universitã â Di Torino; Italia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas (i); Argentina Fil: Turco, Emilia. Universita di Torino; Italia Fil: Silengo, Lorenzo. Universita di Torino; Italia Fil: Hirsch, Emilio. Universita di Torino; Italia Fil: Rege Cambrin, Giovanna. Universita di Torino; Italia Fil: Gambacorti Passerin, Carlo. Universita Degli Studi Di Milano; Italia Fil: Pandolfi, Pier Paolo. Universita di Torino; Italia. Harvard Medical School; Estados Unidos Fil: Papotti, Mauro. Universita di Torino; Italia Fil: Saglio, Giuseppe. Universita di Torino; Italia Fil: Tarone, Guido. Universita di Torino; Italia Fil: Morotti, Alessandro. Universita di Torino; Italia Fil: Brancaccio, Mara. Universita di Torino; Italia

A patient with a typical form of chronic myeloid leukemia was found to carry a large deletion on the derivative chromosome 9q+ and an unusual BCR-ABL transcript characterized by the insertion, between BCR exon 14 and ABL exon 2, of 126 bp derived from a region located on chromosome 9, 1.4 Mb 5′ to ABL. This sequence was contained in the bacterial artificial chromosome RP11-65J3, which in fluorescence in situ hybridization experiments on normal metaphases was found to detect, in addition to the predicted clear signal at 9q34, a faint but distinct signal at 22q11.2, where the BCR gene is located, suggesting the presence of a large region of homology between the two chromosomal regions. Indeed, blast analysis of the RP11-65J3 sequence against the entire human genome revealed the presence of a stretch of homology, about 76 kb long, located approximately 150 kb 3′ to the BCR gene, and containing the 126-bp insertion sequence. Evolutionary studies using fluorescence in situ hybridization identified the region as a duplicon, which transposed from the region orthologous to human 9q34 to chromosome 22 after the divergence of orangutan from the human-chimpanzee-gorilla common ancestor about 14 million years ago. Recent sequence analyses have disclosed an unpredicted extensive segmental duplication of our genome, and the impact of duplicons in triggering genomic disorders is becoming more and more apparent. The discovery of a large duplicon relatively close to the ABL and BCR genes and the finding that the 126-bp insertion is very close to the duplicon at 9q34 open the question of the possible involvement of the duplicon in the formation of the Philadelphia chromosome translocation.