Citations

Colony stimulating factor 3 receptor gene (CSF3R) mutations have recently been associated with chronic neutrophilic leukemia (CNL). Fourteen patients with CSF3R‐mutated CNL (median age 67 years; 57% males) were screened for additional mutations; 8 (57%) and 5 (38%) harbored an ASXL1 and/or SETBP1 mutation (two patients expressed both), respectively. Two patients developed blastic transformation, both SETBP1‐mutated and ASXL1‐unmutated, whereas two other cases evolved into chronic myelomonocytic leukemia (CMML), both ASXL1‐mutated and SETBP1‐unmutated. Median survival was 23.2 months (10 deaths documented). On multivariable analysis mutated ASXL1 (P = 0.009; HR 19.6, 95% CI 2.1–184.1) and thrombocytopenia (P = 0.005; HR 28.8, 95% CI 2.8–298.2) were independently predictive of shortened survival. This study provides information on the natural history of CSF3R‐mutated CNL and identifies mutant ASXL1 and thrombocytopenia as risk factors for survival. The study also suggests pathogenetic roles for SETBP1 and ASXL1 mutations in disease evolution into blast phase disease and CMML, respectively. Am. J. Hematol. 90:653–656, 2015. © 2015 Wiley Periodicals, Inc.

Among 274 patients with chronic myelomonocytic leukemia (CMML) and followed for a median of 17.1 months, blast transformation (BT) occurred in 36 (13%). On multivariable analysis, risk factors for BT were presence of circulating blasts (HR 5.7; 95% CI 2.8–11.9) and female gender (HR 2.6; 95% CI 1.3–5.1); the results remained unchanged when analysis was restricted to CMML‐1. ASXL1/SRSF2/SF3B1/U2AF1/SETBP1 mutational frequencies were not significantly different between time of CMML diagnosis and BT. Median survival post‐BT was 4.7 months (5‐year survival 6%) and better with allogeneic stem cell transplant (SCT) (14.3 months vs. 4.3 months for chemotherapy vs. 0.9 months for supportive care; P = 0.03). Neither karyotype nor mutational status was independently associated with risk of BT or post‐BT survival. We conclude that female patients with CMML and those with circulating blasts are at a higher risk of BT. Post‐BT survival is dismal and our observations suggest consideration of allogeneic SCT prior to BT.Am. J. Hematol. 90:411–416, 2015. © 2015 Wiley Periodicals, Inc.

SummaryAmong 826 patients with primary myelofibrosis (PMF) and analysable metaphases on cytogenetic studies, 352 (42·6%) had abnormal karyotype, of which 240 (68·2%) were sole aberrations and 48 (13·6%) were complex; the most frequent abnormalities were 20q− (23·3%), 13q− (18·2%), +8 (11·1%), +9 (9·9%), chromosome 1q+ (9·7%) and −7/7q− (7·1%). Phenotypic correlates included: abnormal karyotype with anaemia (P = 0·02), leucopenia (P < 0·01) and thrombocytopenia (P < 0·01); complex karyotype with younger age (P = 0·04) and thrombocytopenia (P < 0·01); leucopenia with 20q−, +8 and −7/7q− and thrombocytopenia with 20q− and −7/7q−. Cytopenias were less likely to occur with 13q−. 476 patients were annotated for JAK2/CALR/MPL mutations; abnormal karyotype frequencies were 43% in JAK2, 42% CALR, 33% MPL mutated and 34% triple‐negative cases (P = 0·3). A proportion of patients were also screened for ASXL1, EZH2, IDH1, IDH2, SRSF2, U2AF1 and SF3B1 mutations; in all instances, mutational frequencies were higher in patients with normal karyotype, reaching significance for ASXL1 (P = 0·02) and U2AF1 (P = 0·01). 13q− was associated with mutant CALR (P = 0·03), +9 with mutant JAK2 (P = 0·02) and 20q− with mutant SRSF2 (P = 0·02). The current PMF study provides detailed cytogenetic information and correlations with mutations and clinical phenotype.

Four hundred and nine patients with chronic myelomonocytic leukemia (CMML) were included in the international collaborative study (268 (66%) and 141 (34%) from Mayo clinic and French consortium respectively). Thirty percent displayed an abnormal karyotype, including; 72% sole, 16% two, and 11% complex abnormalities. The most common abnormalities included; +8 (23%), ‐Y (20%), ‐7/7q‐(14%), 20q‐ (8%), +21 (8%), and der(3q) (8%). Patients with an abnormal karyotype were more likely to be elderly (P = 0.03), be anemic (P = 0.0009), have leukocytosis (P = 0.02) with neutrophilia (P = 0.03), demonstrate increased circulating immature myeloid cells (P = 0.0003), peripheral blood blasts (P < 0.0001), and bone marrow blasts (P < 0.0001). ASXL1 (P = 0.04) and SF3B1 (P = 0.03) mutations clustered with an abnormal karyotype, whereas SRSF2 (P = 0.02) mutations occurred more commonly with a normal karyotype. A step‐wise survival analysis resulted in three distinct cytogenetic risk categories: high (complex and monosomal karyotypes), intermediate (all abnormalities not in the high or low risk groups) and low [normal, sole ‐Y and sole der (3q)] with median survivals of 3 [hazard ratio (HR) = 8.1, 95% confidence interval (CI) = 4.6–14.2], 20 (HR = 1.7, 95% CI = 1.2–2.3) and 41 months, respectively. In multivariable analysis, this particular cytogenetic risk stratification remained significant in the context of the Molecular Mayo Model (P < 0.0001), MD Anderson prognostic model (P < 0.0001), the GFM CMML model (P < 0.0001) and was effective in predicting leukemic transformation (P = 0.004). Am. J. Hematol. 89:1111–1115, 2014. © 2014 Wiley Periodicals, Inc.

Key Points Survival in ET is superior to that of PV, regardless of mutational status, but remains inferior to the sex- and age-matched US population. JAK2/CALR/MPL mutational status is prognostically informative in PMF, regarding overall and leukemia-free survival.

AbstractBackgroundVascular events in essential thrombocythemia (ET) are associated with advanced age and thrombosis history. Recent information suggests additional effect from the presence of specific mutations.ObjectivesTo examine the influence of age and thrombosis history on the reported association between mutational status and thrombosis‐free survival in ET.Patients and MethodsAnalysis was performed using a Mayo Clinic cohort of 300 ET patients, and key findings were reanalyzed by including additional 102 Italian patients.ResultsAmong 300 Mayo patients with ET (median age 55 yr, 60% females), mutational frequencies were 53% JAK2, 32% CALR, 3% MPL, and 12% JAK2, CALR and MPL wild type. One hundred and six (35%) patients experienced arterial (n = 75) or venous (n = 43) events, before (n = 55) or after (n = 71) diagnosis. In univariate analysis, compared to JAK2‐mutated cases, JAK2, CALR and MPL wild type (HR 0.31, 95% CI 0.11–0.86), and CALR‐mutated (0.53, 95% CI 0.30–0.92) patients displayed better thrombosis‐free survival. JAK2, CALR, and MPL wild type remained significant (P = 0.03; HR 0.32, 95% CI 0.11–0.9) during multivariable analysis that included age (P = 0.01) and thrombosis history (P = 0.0006); a favorable impact from CALR mutations was of borderline significance (P = 0.1; HR 0.62, 95% CI 0.35–1.1), but became significant (P = 0.02) when multivariable analysis including thrombosis history (P = 0.02) was performed on patients younger than 60 yr of age.ConclusionsThe favorable impact of mutational status on thrombosis‐free survival in ET might be most evident for JAK2, CALR, and MPL wild type patients, whereas the favorable effect from CALR mutations might be confined to young patients.

CALR (calreticulin) trails JAK 2 as the second most mutated gene in essential thrombocythemia (ET). Mutant CALR in ET is a result of frameshift mutations, caused by exon 9 deletions or insertions; type‐1, 52‐bp deletion (p.L367fs*46), and type‐2, 5‐bp TTGTC insertion (p.K385fs*47) variants constitute more than 80% of these mutations. The current study includes a total of 1027 patients divided into test ( n = 402) and validation ( n = 625) cohorts. Among the 402 ET patients in the test cohort, 227 (57%) harbored JAK 2, 11 (3%) Myeloproliferative leukemia virus oncogene ( MPL ), and 114 (28%) CALR mutations; 12% were wild‐type for all three mutations (i.e., triple‐negative). Among the 114 patients with CALR mutations, 51 (45%) displayed type‐1 and 44 (39%) type‐2 variants; compared to mutant JAK 2, both variants were associated with higher platelet and lower hemoglobin and leukocyte counts. However, male sex was associated with only type‐1 ( P = 0.005) and younger age with type‐2 ( P = 0.001) variants. Notably, platelet count was significantly higher in type‐2 vs. type‐1 CALR ‐mutated patients ( P = 0.03) and the particular observation was validated in the validation cohort that included 111 CALR ‐mutated ET patients ( P = 0.002). These findings, coupled with the recent demonstration of preferential expression of mutant and wild‐type CALR in megakaryocytes, suggest differential effects of CALR variants on thrombopoiesis. Am. J. Hematol. 89:E121–E124, 2014. © 2014 Wiley Periodicals, Inc.