Application of PROTACs in Hematological Malignancies--Review / 中国实验血液学杂志

Proteolysis-targeting chimeras (PROTACs) are heterobifunctional small molecules by utilizing the ubiquitin proteasome system (UPS) to degrade proteins of interest. PROTACs have exhibited unprecedented efficacy and specificity in degrading various oncogenic proteins because of their unique mechanism of action, ability to target "undruggable" and mutant proteins. A series of PROTACs have been developed to degrade multiple key protein targets for the treatment of hematologic malignancy. Notably, PROTACs that target BCL-XL, IRAK4, STAT3 and BTK have entered clinical trials. The known PROTACs that have the potential to be used to treat various hematological malignancies are systematically summarized in this review.

Clinical Characteristics of Patients with Ph Mixed Phenotype Acute Leukemia / 中国实验血液学杂志

OBJECTIVE@#To investigate the clinical biological characteristics and prognosis of the patients with mixed phenotype acute leukemia with t(9;22)(q34;q11.2) and/or BCRABL1 (Ph MPAL).@*METHODS@#The morphological, immunological, cytogenetic, and molecular features of 33 in patients with Ph MPAL were retrospectively analyzed in our center from June 2002 to June 2016 according to the scoring proposal of European Group for the Classification of Acute Leukemia(EGIL )1998 and WHO 2008 criteria. All the cases were either treated with acute lymphoblastic leukemia (ALL) induction regimen or combined chemotherapy regimens for both acute lymphoblastic and acute myeloid leukemia,part of which also received tyrosine kinase inhibitor(TKI) and 5 cases underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) after complete remission.@*RESULTS@#Ph MPAL occurred predominantly in male patients (ratio of M/F was 1.75∶1), and a high WBC counts at diagnosis; the WBC count was higher than 30×10/L in 25 patients( 75.8% )， and appeared higher than 100 ×10/L in 13 patients ( 39.4%). Among all the 33 PhMPAL patients, 32 (97.0%) had a myeloid / B-lymphoid (M/B) phenotype， and 1 case(3.0%) had a myeloid/ B-lymphoid/ T-lymphoid/ (M/B/T) phenotype. There was no patients displayed myeloid / T-lymphoid (M/T) or B-lymphoid/ T-lymphoid/ (B/T) phenotype. 19 of all cases(57.6%) met the diagnosis criteria of PhMPAL based on EGIL 1998 criteria, while the remaining 14 cases can be diagnosed as Ph MPAL by WHO 2008 classification,but excluded as PhMAPL by EGIL 1998.Karyotype analysis was successfully performed in 31 cases, and out of them 13 (41.9%) had a sole Ph chromosome, 10 (32.3%) had additional chromosome aberration and Ph chromosome was not found in 8 cases (25.8%) .In 31 patients the fusion gene BCR/ABL (P190、P210) was detected,including 17 (54.8%) cases with the p190 BCR/ABL transcript, 8 (25.8%) cases with the p210 BCR/ABL transcript, 4 (12.9%) expressing both transcripts and 2 (6.5%) without any one of these 2 transcripts. 24 out of 33 patients (77.4%) achieved complete remission after induction therapy. The median time achieving CR was 43(26-98)days. The CR rate of patients treated with and without imatinib after the first inducion treatment was 81.3% and 46.7%,respectively (P0.05). Within the 17 patients treated with imatinib at induction stage，2 of which became BCR/ABLnegative．At consolidation chemotherapy stage, 9 out of 16 patients became BCR/ABL negative, including 3 patients already subjected to HSCT. The median time reached to BCR/ABL negative was 2.87（1.13-9.20）months.@*CONCLUSION@#Ph MPAL is more common in male, and inclined to high WBC counts at diagnosis. Myeloid/B lymphoid phenotype is more common, and the prognosis of patients with PhMPAL is poor. Imatinib and allogeneic hematopoietic stem cell transplantation may improve survival of patients with PhMPAL.

Spectrum of somatic mutations and their prognostic significance in adult patients with B cell acute lymphoblastic leukemia / 中华血液学杂志

Objective: To investigate the spectrum of gene mutations in adult patients with B-acute lymphoblastic leukemia (B-ALL), and to analyze the influences of different gene mutations on prognosis. Methods: DNA samples from 113 adult B-ALL patients who administered from June 2009 to September 2015 were collected. Target-specific next generation sequencing (NGS) approach was used to analyze the mutations of 112 genes (focused on the specific mutational hotspots) and all putative mutations were compared against multiple databases to calculate the frequency spectrum. The impact of gene mutation on the patients' overall survival (OS) and recurrence free survival (RFS) was analyzed by the putative mutations through Kaplan-Meier, and Cox regression methods. Results: Of the 113 patients, 103 (92.0%) harbored at least one mutation and 29 (25.6%) harbored more than 3 genes mutation. The five most frequently mutated genes in B-ALL are SF1, FAT1, MPL, PTPN11 and NRAS. Gene mutations are different between Ph+ B-ALL and Ph- B-ALL patients. Ph- B-ALL patients with JAK-STAT signal pathway related gene mutation, such as JAK1/JAK2 mutation showed a poor prognosis compared to the patients without mutation (OS: P=0.011, 0.001; RFS: P=0.014,<0.001). Patients with PTPN11 mutation showed better survival than those without mutation, but the difference was not statistically significant (P value > 0.05). Besides, in Ph+ B-ALL patients whose epigenetic modifications related signaling pathway genes were affected, they had a worse prognosis (OS: P=0.038; RFS: P=0.047). Conclusion: Gene mutations are common in adult ALL patients, a variety of signaling pathways are involved. The frequency and spectrum are varied in different types of B-ALL. JAK family gene mutation usually indicates poor prognosis. The co-occurrence of somatic mutations in adult B-ALL patients indicate the genetic complex and instability of adult B-ALL patients.