Estimation of diagnosis and prognosis in ET by assessment of CALR and JAK2V617F mutations and laboratory findings: a meta-analysis.

BACKGROUND: Essential thrombocythemia (ET) is a benign disease with slow progress in which thrombosis is a cause of mortality. JAK2V617F and calreticulin (CALR) are the most frequent mutations in this disease. In this systematic review and meta-analysis, we compared the prevalence of JAK2V617F and CALR mutations in ET and examined the incidence of thrombosis and other hematologic indices. METHODS: After choosing MeSH keywords, including essential thrombocythemia, JAK2V617F, calreticulin, prognosis, and diagnosis, as well as searching Medline/PubMed and Scopus, 12 papers were selected. Data were pooled, and summary prevalence and OR were estimated using either a random-effects model or a fixed-effects model. RESULTS: The frequency of JAK2V617F and CALR shows heterogeneity in Caucasian population [JAK2V617 I 2% = 84.3, P < 0.001, 95% CI 0.56 (0.51-0.61)], [CALR I 2% = 96.1, P < 0.001, 95% CI 0.23 (0.15-0.31)]. The prevalence of JAK2V617F and CALR was 0.57 (95% CI 0.53-0.61), I 2% = 79.3 and 0.22 (95% CI 0.16-0.27), I 2% = 94, respectively. JAK2V617F positive ET was associated with increasing odds of thrombosis [OR 2.35 (95% CI 1.83-3.02), P < 0.001]. The incidence of splenomegaly was not statistically different between these two mutations. Hemoglobin, platelet, and WBC count did not affect the risk of thrombosis. CONCLUSIONS: Detection of CALR mutation is helpful for molecular diagnosis of ET patients as well as JAK2V617F. Due to reduction of thrombosis in CALR-positive patients, it can be stated that such patients have less thrombotic disorders and better prognosis relative to patients bearing JAK2V617F mutation. Therefore, detection of mutation in CALR and JAK2V617F may contribute to diagnosis and prognosis of ET patients.

Signaling and molecular basis of bone marrow niche angiogenesis in leukemia.

Angiogenesis, the process of blood vessel formation, is necessary for tissue survival in normal and pathologic conditions. Increased angiogenesis in BM niche is correlated with leukemia progression and resistance to treatment. Angiogenesis can interfere with disease progression and several angiogenic (such as vascular growth factors) as well as anti-angiogenic factors (i.e. angiostatin) can affect angiogenesis. Furthermore, miRs can affect the angiogenic process by inhibiting angiogenesis or increasing the expression of growth factors. Given the importance of angiogenesis in BM for maintenance of leukemic clones, recognition of angiogenic and anti-angiogenic factors and miRs as well as drug resistance mechanisms of leukemic blasts can improve the therapeutic strategies. We highlight the changes in angiogenic balance within the BM niche in different leukemia types. Moreover, we explored the pathways leading to drug resistance in relation to angiogenesis and attempted to assign interesting candidates for future research.