Clinical and Hematological Relevance of JAK2V617F, CALR, and MPL Mutations in Vietnamese Patients with Essential Thrombocythemia.

Background: The picture of Vietnamese patients with essential thrombocythemia (ET) remains mostly undetermined. Our study intended to determine the frequency of JAK2V617F, CALR exon 9, and MPL exon 10 mutations as well as to analyze clinical characteristics associated with different mutational status in Vietnamese ET patients. Methods: We explored mutations of JAK2V617F, MPL, and CALR from 395 patients using allele specific oligonucleotide ­ polymerase chain reaction and Sanger sequencing techniques; then, the clinical and hematological features were compared according to mutation patterns. Results: We found that JAK2V617F, CALR exon 9, and MPL exon 10 mutations were present in 56.2%, 27.6%, and 1% of the 395 patients with ET, respectively. Twelve different types of CALR mutation were detected in 109 patients, with the CALR type 1 mutation (c.1099_1150del; L367fs*46) was the most common, followed by CALR type 2 mutation (c.1154_1155insTTGTC; K385fs*47). The JAK2V617F-positive patients had older age, higher white blood cell counts and higher hemoglobin levels but lower platelet counts than patients with CALR mutations or patients negative for triple tests. There was no significant difference regarding sex ratio, white blood cell counts, platelet counts and hemoglobin levels among CALR mutation subtypes. Conclusion: we reported high frequency of JAK2V617F, CALR, and MPL mutations in Vietnamese patients with ET and underscored the importance of combined genetic tests for diagnosis and classification of ET into different subtypes.

Establishment and characterization of A novel Philadelphia-chromosome positive chronic myeloid leukemia cell line, TCC-S, expressing P210 and P190 BCR/ABL transcripts but missing normal ABL gene.

A novel Philadelphia-chromosome positive (Ph+) cell line, TCC-S, has been established from a patient with Ph+ chronic myeloid leukemia (CML) in the blastic crisis. TCC-S cells were shown to express both P210 and P190 BCR/ABL transcripts by reverse transcriptase-polymerase chain reaction (PCR), although quantitative-PCR revealed that TCC-S cells mainly expressed P210 BCR/ABL transcript. Karyotype analysis revealed several triploid clones which constantly harbored two der(9)del(9) (p12)t(9;22) (q34;qll)s and two del(9) (q21)s. The der(9)del(9) (p12)t(9;22) (q34;q11) is rarely found in other CML cell lines. Moreover, to the best of our knowledge, del(9) (q21) resulting in missing of a restrict region including normal ABL gene has not been found among CML cell lines previously described. Thus, TCC-S cells with only BCR/ABL gene and no normal ABL gene may be a useful tool for functional study of ABL in Ph+ CML.