The clinical relevance of broad mutational screening of myeloproliferative neoplasms at diagnosis.

Introduction: Myeloproliferative neoplasm (MPN) is a heterogenous group of hematological malignancies including polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). JAK2V617F is the most frequent driver mutation in all three entities, but in PMF and ET mutations in CALR and MPL are also frequent. Mutations seen in additional genes are also often the same regardless of subtype of MPN. The aim of this study was to analyze a population based MPN cohort for genetic variants with prognostic value that can guide clinical decisions. Methods: MPN patients from Western Sweden diagnosed between 2008-2013 (n=248) were screened for mutations in 54 genes associated with myeloid malignancy. Results: Mutations in the genes SRSF2 and U2AF1 correlated significantly with impaired overall survival but did not correlate to increased risk for vascular events, neither before nor after diagnosis. Rather, mutations in these genes showed an association with disease transformation. Several recurrent gene variants with allele frequency close to 50% were confirmed to be germline. However, none of these variants was found to have an earlier onset of MPN. Discussion: In conclusion, we identified gene mutations to be independent markers of impaired survival in MPN. This indicates the need for more individualized assessment and treatment of MPN patients and a wider gene mutation screening already at diagnosis. This could ensure the identification of patients with high-risk mutations early on. In addition, several genetic variants were also identified as germline in this study but gave no obvious clinical relevance. To avoid conclusions from non-informative genetic variants, a simultaneous analysis of normal cell DNA from patients at diagnosis should be considered.

Survival and risk of vascular complications in myelofibrosis-A population-based study from the Swedish MPN group.

OBJECTIVE: To gain knowledge of underlying risk factors for vascular complications and their impact on life expectancy in myelofibrosis. METHODS: From a cohort of 392 myelofibrosis patients registered in the Swedish MPN registry 58 patients with vascular complications during follow-up were identified. Patients with vascular complications were compared with both 1:1 matched controls and the entire myelofibrosis cohort to explore potential risk factors for vascular complications and their impact on survival. RESULTS: Incidence of vascular complications was 2.8 events per 100 patient-years and the majority of complications were thrombotic. Patients with complications were significantly older and had lower hemoglobin when compared to the entire cohort. In the case-control analysis, no significant risk factor differences were observed. The major cause of death was vascular complications and median survival was significantly impaired in patients with vascular complications (48 months) compared to controls (92 months). Inferior survival in patients with vascular complications was found to be dependent on IPSS risk category in a Cox regression model. CONCLUSION: Vascular complications have a considerable impact on survival in MF. At diagnosis, risk assessment by IPSS does not only predict survival but is also associated with the risk of vascular complications.

ASXL1 mutations, previous vascular complications and age at diagnosis predict survival in 85 WHO-defined polycythaemia vera patients.

Polycythaemia vera (PV) patients have an overall comparatively favourable prognosis, but disease progression is very heterogeneous and life-threatening thrombosis and bleedings are frequent complications in untreated disease. Moreover, transformation to more severe secondary myelofibrosis and acute myeloid leukaemia can occur. The aim of this study was to identify gene mutations that could be used together with clinical data as prognostic markers to guide treatment decisions in PV patients. A well-characterized WHO-defined cohort of PV patients was used. Clinical data and blood values were evaluated and a myeloid sequencing panel was used to screen for additional mutations other than the diagnostic JAK2 V617F and JAK2 exon 12 mutations. In 78% of the PV patients, at least one mutation additional to JAK2 V617F was detected. Additional mutations in genes coding for epigenetic modifiers, like TET2, DNMT3A and ASXL1, were most frequent. When correlated to overall survival, mutations in ASXL1 were significantly associated with inferior survival. In an attempt to obtain prognostic guidance in a larger number of patients, the presence of ASXL1 mutations was combined with age and vascular complications prior to diagnosis. Based on these data we were able to define three risk groups that predicted survival.

Highly reduced survival in essential thrombocythemia and polycythemia vera patients with vascular complications during follow-up.

OBJECTIVE: To explore the relative importance of risk factors, treatments, and blood counts for the occurrence of vascular complications and their impact on life expectancy in essential thrombocythemia (ET) and polycythemia vera (PV). METHODS: Nested case-control study within the Swedish MPN registry. From a cohort of 922 ET patients and 763 PV patients, 71 ET and 81 PV cases with vascular complications were compared with matched controls. RESULTS: Incidence of vascular complications was 2.0 and 3.4 events per 100 patient-years in ET and PV, respectively. At diagnosis, no significant risk factor differences were observed between cases and controls in neither of the diseases. At the time of vascular event, ET complication cases did not differ significantly from controls but in PV, cases had significantly higher WBCs and were to a lesser extent treated with anti-thrombotic and cytoreductive therapy. Life expectancy was significantly decreased in both ET and PV cases compared with controls. CONCLUSIONS: The risk of vascular complications is high in both ET and PV, and these complications have a considerable impact on life expectancy. The protective effect of anti-thrombotic and cytoreductive therapy for vascular complications in PV underscores the importance of avoiding undertreatment.

Increased incidence of another cancer in myeloproliferative neoplasms patients at the time of diagnosis.

Several studies have reported an increased incidence of coexistent cancer in patients with myeloproliferative neoplasms (MPN), and myelosuppressive treatment has been speculated to be one of the causes. In this study, we have concentrated on malignancies diagnosed before the MPN diagnosis to eliminate the possible influence of MPN treatment. The patients were recruited from the Swedish and Norwegian cancer registries. One thousand seven hundred and 45 patients from the Swedish MPN Quality Registry and 468 patients from the Norwegian National Cancer Registry were included in this study covering a 3-yr period. The results show that primary concurrent cancer is higher among patients with MPN compared to the general population. When pooled together, the Swedish and the Norwegian cohort showed increased prevalence of all types of cancer in general compared with the general population, standard prevalence ratio (SPR) of 1.20 (95% CI 1.07-1.34). Significantly high SPRs were reached for skin malignant melanoma [1.89 (95% CI 1.33-2.62)], prostate cancer [1.39 (95% CI 1.11-1.71)], and hematologic cancer [1.49 (95% CI 1.00-2.12)]. In the polycythemia vera group, the risk of having prior malignant melanoma of the skin was significant, with an SPR of 2.20 (95% CI 1.17-3.77). For patients with essential thrombocythemia and primary myelofibrosis, no significant risks were found. Coexisting cancers have a high impact on the treatment strategies of MPN, as it narrows down the treatment options. Chronic inflammation, as a common denominator of MPN with other cancers, can catalyze each other's existence and progression.