Telomeric repeat-containing RNA is dysregulated in acute myeloid leukemia.

TERRA (telomeric repeat-containing RNA) is a class of long noncoding RNAs transcribed from subtelomeric and telomeric regions. TERRA binds to the subtelomeric and telomeric DNA-forming R-loops (DNA-RNA hybrids), which are involved in telomere maintenance and telomerase function, but the role of TERRA in human cells is not well characterized. Here, we comprehensively investigated for the first time TERRA expression in primary human hematopoietic cells from an exploratory cohort of patients with acute myeloid leukemia (AML), patients with acute lymphoblastic leukemia (ALL), patients with telomere biology disorder (TBD), and healthy subjects. TERRA expression was repressed in primary human hematopoietic cells, including healthy donors, patients with ALL, and patients with TBD, irrespective of their telomere length, except for AML. A second cohort comprising 88 patients with AML showed that TERRA was overexpressed in an AML subgroup also characterized by higher R-loop formation, low TERT and RNAseH2 expression, and a paucity of somatic splicing factor mutations. Telomere length did not correlate with TERRA expression levels. To assess the role of TERRA R-loops in AML, we induced R-loop depletion by increasing RNAseH1 expression in 2 AML cell lines. Decreased TERRA R-loops in AML cell lines resulted in increased chemosensitivity to cytarabine. Our findings indicate that TERRA is uniformly repressed in primary human hematopoietic cells but abnormally expressed in an AML subset with low telomerase.

Peripheral lymphocyte subsets as predicting factors for molecular recurrence after imatinib discontinuation in a phase 2 imatinib discontinuation trial in patients with chronic myeloid leukemia.

INTRODUCTION: Treatment-free remission (TFR) is successful in half of the patients with chronic myeloid leukemia who discontinue Imatinib (IM) after sustained molecular response. METHODS: In a prospective trial, we used pioglitazone for 3 months before stopping IM in 30 patients. Percentages of peripheral blood lymphocyte subsets were assessed before and after treatment. The relation of these data with duration of IM treatment and TRF were examined. RESULTS: The median time of IM treatment was 117.6 months. After discontinuation, 11 patients had molecular recurrence after 5.2 months (2.4 - 30). The observation time for those remaining in TFR was 46 (26 - 56) months. The independent factors for the maintenance of TFR were the duration of IM treatment and the percentage of double-positive T cells at IM stop. CONCLUSION: A longer treatment with imatinib was associated with a longer TFR after discontinuation. Pioglitazone could act as an immunomodulator, increasing DP T cells which may contribute to prevent relapse.

Management of chronic myeloid leukemia during pregnancy: a retrospective analysis at a single center

ABSTRACT We analyzed the management and outcomes of pregnancies of patients with chronic myeloid leukemia at a single center over fifteen years. Among the 203 CML female patients, there were ten pregnancies in seven women, all of them not planned. In three cases, the chronic myeloid leukemia diagnosis was made during pregnancy. Five patients received tyrosine kinase inhibitors in the first weeks of pregnancy and the drug was interrupted until delivery. One patient lost complete cytogenetic response, and two patients lost the hematological response. A patient with a stable major molecular response had two successful pregnancies without loss of response. There were four premature births. There were no maternal adverse events, fetal malformation or death. All patients received Interferon-alpha during gestation, and two received hydroxyurea for a short period. Leukapheresis was performed in two patients for hyperleukocytosis control. One patient with sickle cell disease died from disease progression six months after delivery. Conclusions: The tyrosine kinase inhibitors ministration should be interrupted during pregnancy. Patients should be advised to achieve a stable and deep molecular response if they plan to conceive, to avoid the risk of disease progression.

Cardiovascular Risk and Cardiovascular Events in Patients With Chronic Myeloid Leukemia Treated With Tyrosine Kinase Inhibitors.

BACKGROUND: Cardiovascular events (CVEs) have been observed in patients with chronic myeloid leukemia treated with second-generation tyrosine kinase inhibitors. PATIENTS AND METHODS: We retrospectively evaluated the incidence of CVEs on 233 consecutive patients with chronic myeloid leukemia, of which 116 were treated with imatinib, 75 with dasatinib, and 42 with nilotinib. The median follow-up was 2047, 1712, and 1773 days, respectively. RESULTS: The cumulative incidence of CVEs was 4.29%. Three events occurred during dasatinib treatment, 6 during nilotinib treatment, and none during imatinib treatment (P ≤ .001). Arterial occlusive events occurred in 2 (2.6%) of 75 patients treated with dasatinib and in 6 (14.2%) of 42 patients treated with nilotinib (P ≤ .001). Furthermore, all of them occurred in patients with high-risk (n = 2) and very high-risk (n = 6) cardiovascular risk, contributing to 4.3% of mortality. CONCLUSION: CVEs were more frequent in patients treated with second-generation tyrosine kinase inhibitors. Arterial occlusive events were more frequent in patients treated with nilotinib, with high and very high cardiovascular risk.