TPO, but not soluble-IL-6 receptor, levels increase after anagrelide treatment of thrombocythemia in chronic myeloproliferative disorders.

Anagrelide is often used in the treatment of thrombocythemia in myeloproliferative disease (MPD), but information concerning effects of treatment on cytokines involved in regulation of blood platelet levels is limited. Here, we investigated serum levels of thrombopoietin (TPO) and soluble IL-6 receptor (sIL-6R) in relation to response to treatment with and plasma concentrations of anagrelide. Samples from 45 patients with thrombocythemia due to MPD (ET=31, PV=14), being treated with anagrelide for 6 months, were analyzed for TPO, sIL-6R and anagrelide levels. The mean baseline platelet count was 983x10(9)/L. A reduction of platelets to <600 in asymptomatic or <400 x 10(9)/L in symptomatic patients was defined as a complete remission (CR), a reduction with >50% of baseline as partial remission, and <50% reduction as failure. At 6 months, 35 patients were in CR, 1 had a partial remission and 9 were treatment failures. For all patients, there was an increase in TPO of 44% from baseline; this change was more pronounced for patients with partial remission and failure. sIL-6R levels did not change significantly. There was no correlation between levels of anagrelide and cytokine levels at 6 months, and changes of cytokine levels did not relate to changes of platelet counts. Thus, a pronounced increase of TPO levels after 6 months of anagrelide treatment indicated that this treatment affected a major regulatory mechanism for megakaryocyte and platelet formation in MPD.

Adverse effects and benefits of two years of anagrelide treatment for thrombocythemia in chronic myeloproliferative disorders.

BACKGROUND AND OBJECTIVES: Although anagrelide is widely used in the treatment of thrombocythemia in myeloproliferative diseases, there is currently limited information on the efficacy and toxicity of its long-term use. This prospective study investigated clinical toxicity and efficacy of anagrelide during two years of treatment. DESIGN AND METHODS: A multicenter, open, phase II study of anagrelide treatment was performed by the Swedish Myeloproliferative Disorder Study Group. The study included 60 patients with thrombocythemia due to myeloproliferative disease, 42 with essential thrombocythemia (ET), 17 with polycythemia vera (PV) and one with myelofibrosis (MF). RESULTS: Complete response (CR), defined as a platelet count <400x10(9)/L in symptomatic patients and < 600x10(9)/L in asymptomatic patients was achieved in 67% of the patients and partial response (PR) in 6%. The response rate was higher in patients with ET than in those with PV (p = 0.05). Primary treatment failure occurred in 27% due to lack of efficacy at a tolerable dose (n=13) or insufficient platelet response without side effects (n=3). In addition, another 14 patients withdrew from treatment before the end of the two-year period due to side effects. Side effects included palpitations (70%), headache (52%), nausea (35%), diarrhea or flatulence (33%), edema (22%) and fatigue (23%). Patients and doctors rated their satisfaction with the anagrelide treatment on a 10-grade scale from 7.6 at 3 months to >9 at 24 months. After two years, 50% (n=30) of the patients continued anagrelide treatment. INTERPRETATION AND CONCLUSIONS: Side effects and toxic discontinuation rates were higher than in previous studies, probably because this is the first long-term prospective study of the feasibility and toxicity of anagrelide treatment. Nevertheless, anagrelide is a valuable alternative for treatment of thrombocythemia in myeloproliferative disorders for patients who tolerate the drug well.

Cytogenetic and morphologic subgroups of myelodysplastic syndromes in relation to occupational and hobby exposures.

OBJECTIVES: This study investigated the association between occupational and hobby exposure and the risk of myelodysplastic syndromes (MDS) while focusing on differential patterns of clonal chromosome aberrations and morphologic subgroups. METHODS: A case-referent study was conducted with 330 MDS patients investigated cytogenetically in 1976-1993 (cases) and matched referents. Telephone interviews with either the person or a next-of-kin were used. The participation rate of the cases and referents was 85% and 60%, respectively. Information was obtained from the next-of-kin more often for the cases (88%) than for the referents (26%). Occupational hygienists assessed the exposure using interview data on worktasks and hobbies. Associations with disease risk were evaluated for 10 exposures with a logistic regression analysis. RESULTS: The investigated exposures were generally not associated with cytogenetically abnormal MDS. Effect estimates for specific cytogenetic or morphologic subgroups were generally imprecise. Occupational exposure to extremely low-frequency magnetic fields (EMF) was associated with MDS with a normal karyotype [odds ratio (OR) 2.0, 95% confidence interval (95% CI) 1.0-4.0]. The exposure-response association was consistent for intensity but inconclusive for duration. A decreased risk was observed for MDS, irrespective of karyotypic pattern, among farmers and farmhands (OR 0.53, 95% CI 0.35-0.81). CONCLUSIONS: Cytogenetically abnormal MDS was generally not associated with occupational or hobby exposure to known or suspected genotoxic agents. However, exposure prevalences and intensities were low for several agents. An association was suggested between occupational exposure to EMF and MDS with a normal karyotype. Biases due to differential information quality and selective participation cannot be ruled out.

Trisomy 8 as the sole chromosomal aberration in myelocytic malignancies: a multicolor and locus-specific fluorescence in situ hybridization study.

Trisomy 8 is the most common chromosomal aberration in myelocytic malignancies, occurring both as a sole change as well as in addition to other abnormalities. In spite of this, next to nothing is known about its pathogenetic importance or its molecular genetic consequences. Possible mechanisms involved in the transformation process include dosage effects of genes mapping to chromosome 8 and presence of specific mutations or cryptic fusion genes on the duplicated chromosome. In the latter case, +8 would be secondary to a cryptic primary rearrangement and not involved in leukemogenesis as such, but rather in tumor evolution. Although hidden genetic changes have been found in some trisomies, for example, mutations in KIT in acute myelocytic leukemia (AML) with +4 and in MET in hereditary papillary kidney carcinoma with trisomy 7, none associated with +8 have so far been discovered. To address this issue, we have investigated a total of 13 cases of AML, myelodysplastic syndromes, and chronic myeloproliferative disorders with trisomy 8 as the sole chromosomal anomaly. All cases were studied by combined binary ratio multicolor fluorescence in situ hybridization (FISH) and with FISH using locus-specific probes for both arms of chromosome 8, the subtelomeric regions of 8p and 8q, and the leukemia-associated genes FGFR1, MOZ, ETO, and MYC. No cryptic changes were detected, thus excluding the possibility of gross genetic rearrangements or aberrations involving these loci on chromosome 8.

Multicolor COBRA-FISH analysis of chronic myeloid leukemia reveals novel cryptic balanced translocations during disease progression.

During the initial indolent chronic phase of chronic myeloid leukemia (CML), the t(9;22)(q34;q11), resulting in the Philadelphia chromosome (Ph), is usually the sole cytogenetic anomaly, but as the disease progresses into the accelerated phase (AP), and eventually into aggressive blast crisis (BC), secondary aberrations, mainly unbalanced changes such as +8, i(17q), and +Ph, are frequent. To date, molecular genetic studies of CML BC have mainly focused on alterations of well-known tumor-suppressor genes (e.g., TP53, CDKN2A, and RB1) and oncogenes (e.g., RAS and MYC), whereas limited knowledge is available about the molecular genetic correlates of the unbalanced chromosomal abnormalities. Balanced secondary changes are rare in CML AP/BC, but it is not known whether cryptic chromosomal translocations, generating fusion genes, may be responsible for disease progression in a subgroup of CML. To address this issue, we used multicolor combined binary ratio fluorescence in situ hybridization (FISH), which allows the simultaneous visualization of all 24 chromosomes in different colors, verified by locus-specific FISH in a series of 33 CML cases. Two cryptic balanced translocations, t(7;17)(q32-34;q23) and t(7;17)(p15;q23), were found in two of the five cases showing the t(9;22) as the only cytogenetic change. Using several BAC clones, the breakpoints at 17q23 in both cases were mapped within a 350-kb region. In the case with the 7p15 breakpoint, a BAC clone containing the HOXA gene cluster displayed a split signal, suggesting a possible creation of a fusion gene involving a member of the HOXA family. Furthermore, one case with a partially cryptic t(9;11)(p21-22;q23) and an MLL rearrangement as well as a previously unreported t(3;10)(p22;p12-13) were identified. Altogether, a refined karyotypic description was achieved in 12 (36%) of the 33 investigated cases, illustrating the value of using multicolor FISH for identifying pathogenetically important aberrations in CML AP/BC.

Balanced chromosome abnormalities inv(16) and t(15;17) in therapy-related myelodysplastic syndromes and acute leukemia: report from an international workshop.

The Workshop identified 48 unselected patients with therapy-related myelodysplastic syndrome or acute myeloid leukemia (t-MDS/t-AML) and inv(16), and 41 patients with t(15;17) after chemotherapy (CT) and/or radiotherapy (RT) for a malignant or nonmalignant disease. The primary diseases were: breast cancer, 33 patients; lymphomas, 24 patients; various other solid tumors, 30 patients; and nonmalignant diseases, 2 patients. The general type of previous therapy was RT only in 10 patients with an inv(16) and in 12 patients with a t(15;17), alkylating agents plus topoisomerase II inhibitors in 24 patients with an inv(16) and in 18 patients with a t(15;17), topoisomerase II inhibitors only in 5 patients with an inv(16) and in 2 patients with a t(15;17), alkylating agents only in 6 patients in each subgroup, and other types of chemotherapy in 3 patients in each subgroup. Most CT-treated patients (69%) also received RT. The latency period to development of t-MDS/t-AML was short: a median of 22 months in patients with inv(16) and 29 months in patients with t(15;17). Twenty-six patients (54%) with an inv(16) and 17 patients (41%) with a t(15;17) had additional cytogenetic abnormalities, which were unrelated to age and survival in both subgroups. Trisomy of chromosomes 8, 21, and 22 and del(7q) were the most frequent additional abnormalities in the inv(16) subgroup, whereas +8, -5, and del(16q) were most frequent in the t(15;17) subgroup. The disease was overt t-AML in 38/48 patients (79%) with an inv(16) and in 38/41 patients (93%) with a t(15;17). Thirty-three of 39 intensively treated patients (85%) with an inv(16) obtained a complete remission, whereas 24 of 35 intensively treated patients (69%) with a t(15;17) obtained a complete remission. The median overall survival of intensively treated patients was 29 months in both cytogenetic subgroups. In the inv(16) subgroup, patients younger than 55 years of age had a longer survival when compared with older patients (P = 0.006). The study supports the observation that t-MDS/t-AML with inv(16) and t(15;17) is often associated with prior therapy with topoisomerase II inhibitors; however, a notable finding was the high frequency of treatment with only radiotherapy, 29% of t(15;17) and 21% of inv(16). Response rates to intensive chemotherapy in this study were comparable to those of de novo disease.