Molecular Basis and Clinical Application of Growth-Factor-Independent In Vitro Myeloid Colony Formation in Chronic Myelomonocytic Leukemia

Significance of cardiovascular comorbidity in patients with chronic myelomonocytic leukemia

In a retrospective study, we analyzed the prevalence of common cardiovascular comorbidities in 310 patients with chronic myelomonocytic leukemia (CMML), their potential prognostic impact, and potential correlations with laboratory and molecular features. 115 (36%) patients had a documented cardiovascular comorbidity. In these patients, coronary heart disease 41/115 (36%), atrial fibrillation 34/115 (29%), and hypertension 75/115 (64%) were documented. None of these conditions had a significant impact on survival. Unexpectedly, patients with cardiovascular comorbidity had a lower number of circulating blasts and a lower prevalence of EZH2 mutations. Moreover, time to transformation was significantly longer in these patients. Cardiovascular comorbidity does not seem to have a major impact on prognosis in CMML patients. The unexpected lower transformation rate in these patients needs to be further investigated.

Multistep pathogenesis of chronic myelomonocytic leukemia in patients

Background

A multistep pathogenesis of myeloid leukemia including mutations in epigenetic, spliceosome, and signaling genes has been recently demonstrated in a preclinical model but is poorly validated in patients.

Methods

Clinical, phenotypic, and biologic features were compared between three distinct molecularly defined CMML cohorts including TET2 monomutated patients (T, n = 10), TET2/SRSF2 bimutated patients (TS, n = 19), and patients who had NRAS mutations in addition to TET2/SRSF2 comutations (TSN, n = 14).

Results

Median survival was 90, 45, and 9 months, respectively (p = .001). Whereas no patient in the T and TS group transformed into acute myeloid leukemia (AML), 6/14 patients in the TSN group had AML at study entry or transformed during follow‐up. Leukocyte counts, blast cell counts, and LDH levels were significantly higher in TSN vs. TS and T, respectively, whereas hemoglobin and platelet values were not significantly different. Increased growth factor‐independent myeloid colony formation was restricted to TSN but not found in T and TS, respectively. The proportion of patients showing in vitro myelomonocytic skewing in T, TS, and TSN was 0%, 56%, and 100%, respectively (p = .010).

Conclusion

Our results demonstrate that the model of multistep pathogenesis in CMML can be recapitulated in patients regarding clinical, phenotypic, and biologic features.

Molecular Pathogenesis of Chronic Myelomonocytic Leukemia and Potential Molecular Targets for Treatment Approaches

Numerous examples in oncology have shown that better understanding the pathophysiology of a malignancy may be followed by the development of targeted treatment concepts with higher efficacy and lower toxicity as compared to unspecific treatment. The pathophysiology of chronic myelomonocytic leukemia (CMML) is heterogenous and complex but applying different research technologies have yielded a better and more comprehensive understanding of this disease. At the moment treatment for CMML is largely restricted to the unspecific use of cytotoxic drugs and hypomethylating agents (HMA). Numerous potential molecular targets have been recently detected by preclinical research which may ultimately lead to treatment concepts that will provide meaningful benefits for certain subgroups of patients.