[The genetic characteristics of BCR-ABL-negative myeloproliferative neoplasms].

Objective: To explore the relationship between driver gene mutation (JAK2, MPL and CALR) and disease type in BCR-ABL negative myeloproliferative neoplasms (MPNs) including primary myeloid fibrosis (PMF), essential thrombocytosis (ET) and polycythemia vera (PV). Methods: A total of 32 MPN related genes were detected by high-throughput sequencing in 156 MPN patients. The relationships between disease type and patients' general performance, the characteristics of driver gene mutations, concomitant gene mutations were analyzed. Results: In the population with JAK2 V617F positive mutation, the proportion of patients over 60 years old in PMF was higher than that with ET or PV. By high-throughput sequencing, 22 concomitant gene mutations were detected in 46 patients with JAK2, MPL or CALR mutations, including 4 (8.3%) in PV, 20 (29.4%) in ET, and 22 (55.0%) in PMF. DNMT3A mutation was detected only in patients with PV, while splicing factor related genes including SF3B1, SRSF2 and U2AF1 were only accompanied by PMF. According to the variation allele frequency (VAF) value of JAK2 V617F mutation, the VAF value associated with PV was the highest (68.15%), followed by PMF (37.7%) and ET (23%). However, there were significant differences in the incidence of JAK2 V617F homozygous among 3 different diseases. In patients with JAK2 mutation, the proportion of other gene mutations in PV and ET was significantly lower than that in PMF. Conclusions: Under the condition of common driver gene mutations (JAK2, MPL and CALR), patients' age, VAF value and homozygous state, concomitant gene mutations are closely related to different disease type. These correlations help to improve clinical understanding of disease characteristics and risk assessment.

[Clonal heterogeneity and its prognostic significance in acute lymphoblastic leukemia].

Objective: To explore the characteristics and clinical significance of clonal heterogeneity in patients with acute lymphoblastic leukemia(ALL). Methods: From January 2016 to June 2019, 170 newly diagnosed ALL patients were enrolled in the Department of Hematology, Henan Cancer Hospital, including 93 males and 77 females, with a median age of 17 (2-80) years. Fifty-two ALL-related genes were detected by high-throughput sequencing technique. The clonal heterogeneity of mutations was analyzed according to the variant allele frequency (VAF) and the results of flow cytometry. The prognostic value of mutations was also evaluated. Results: Gene mutations were detected in 121 (71.2%, 121/170) patients, of which 2 or more clones were detected in 18 (52.9%, 18/34) T-cell acute lymphoblastic leukemia patients, while only 23 (16.9%, 23/136) B-cell acute lymphoblastic leukemia patients were positive of multiple mutations (P<0.01).Gene mutation-related clonal heterogeneity analysis showed that 2 or more clones were frequent in patients with NOTCH1 mutations (13/19 patients) (P<0.01). Event free survival (EFS) in patients with 3 or more clones was significantly lower than other patients (χ(2)=10.330, P=0.016). Child ALL patients had similar result, that multiple clones predicted lower overall survival (OS) and EFS (OS: χ(2)=7.974, P=0.047; EFS: χ(2)=10.860, P=0.013). Conclusion: Clonal heterogeneity in ALL patients is closely related to the different origin of lymphocyte lineages and the age of onset, which may reveal the nature of the disease and predict the clinical outcome.

[Analysis of pregnancy outcomes of polycystic ovary syndrome patients after frozen embryo transfer].

Objective: To investigate pregnancy outcomes of the patients with polycystic ovary syndrome (PCOS) after frozen embryo transfer (FET) . Methods: Data of 2 367 PCOS patients received in vitro fertilization-embryo transfer [including fresh embryo transfer (fET) and FET] from January 2009 to December 2015 in Peking University Third Hospital were evaluated retrospectively. The basal characteristics, pregnancy complications and outcomes were analyzed, then identified the relative factors followed. Results: Totally 2 367 patients received in vitro fertilization-embryo transfer: 1 106 were treated with fET, and the rest 1 261 cases were treated with FET. The incidence of gestational diabetes mellitus (GDM) was lower in FET group [4.04%(51/1 261) versus 6.15%(68/1 106)], the difference was statistically significant (P<0.05). Singletons born after FET had higher birth weight than fET [(3 406±548) versus (3 360±533) g], the difference was statistically significant (P<0.05). There was no difference of other pregnancy complications between the two groups (all P>0.05). fET was an independent risk factor for GDM (adjusted OR=1.570, 95%CI: 1.075-2.294). Conclusion: Compared with fET, FET could decrease the risk of GDM and receive better neonatal outcomes in patients with PCOS.

[Analysis of clinical significance and prognostic impact of TET2 single nucleotide polymorphism I1762V in patients with acute myeloid leukemia].

Objective: This study aimed to investigate the clinical and prognostic significance of TET2 single nucleotide polymorphism I1762V in patients with acute myeloid leukemia (AML) . Methods: The high-throughput sequencing method was used to sequence 58 hematological tumor-related genes in bone marrow samples from 413 patients with AML. TET2 I1762V and other somatic mutations were annotated and compared with patients' clinical information and prognosis. Results: I1762V was found in 154 patients with AML, which was significantly different from the general population in NyuWa Chinese Population Variant Database (χ(2)=72.4, P<0.001) . I1762V was not related to sex, age, and karyotype of patients with AML (P>0.05) . Patients with I1762V had a significantly higher proportion of NPM1 and KIT gene mutations than others (P<0.001) . NPM1 and KIT mutations were mutually exclusive. The survival analysis results revealed that the overall survival (OS) and progression-free survival (PFS) of patients with AML with I1762V were significantly greater than those of wild-type patients (HR=0.57, P=0.030; HR=0.55, P=0.020) , whereas the OS and PFS in patients with AML with DNMT3A mutation (with or without I1762V mutation) were lower than those of wild-type patients (HR=1.79, P=0.030; HR=1.74, P=0.040) . Conclusion: TET2 SNP I1762V has been linked to AML. I1762V is a prognostic factor of patients with AML, which can be used to guide the treatment and evaluate the prognosis of AML.

[Application and clinical study of clonal heterogeneity analysis in acute myeloid leukemia].

Objective: This study aimed to explore the characteristics and clinical value of clonal heterogeneity in acute myeloid leukemia (AML) . Method: A high-throughput sequencing was carried out to detect 68 related genes in 465 AML patients. Clonal heterogeneity was analyzed based on variant allele frequency (VAF) and flow cytometry results combined with clinical data. Results: Gene mutations were discovered in 338 (81.4%) newly diagnosed patients, and 2 or more clones were significantly increased in patients with DNMT3A, NRAS, and RUNX1 mutations (DNMT3A, χ(2)=15.23; P<0.001; NRAS, χ(2)=19.866; P<0.001; RUNX1, χ(2)=23.647; P<0.001) . The number of clones significantly differed between groups at different ages (χ(2)=17.505, P=0.022) . The proportion of carrying 2 and ≥3 clones increased in patients aged more than 60 years old. There was a significant difference in the clonal heterogeneity between newly diagnosed patients and relapsed or secondary patients (χ(2)=11.302, P=0.010) . Moreover, the proportion of patients with clonal heterogeneity gradually increased according to their prognostic risk (χ(2)=17.505, P=0.022) . Based on the clone analysis, the proportion of primary clones of patients with RUNX1 mutation was higher (χ(2)=4.527, P=0.033) . The analysis of clonal heterogeneity and efficacy demonstrated that patients with three or more clones had significantly lower overall survival (OS) and progression-free survival (PFS) compared to other patients (OS, χ(2)=13.533; P=0.004; PFS, χ(2)=9.817; P=0.020) , while in the intermediate-risk group, patients with a significant clonal heterogeneity also exhibited a significant decrease in PFS (χ(2)=10.883, P=0.012) . Cox regression multivariate analysis revealed that carrying three or more clones was an independent factor affecting prognosis, and OS and PFS were significantly lower than those of patients without clones (OS, HR=3.296; 95% CI, 1.568-6.932; P=0.002; PFS, HR=3.241; 95% CI, 1.411-7.440; P=0.006) . Conclusion: Clonal heterogeneity may reflect the biological characteristics of a tumor, suggesting its drug resistance, refractory, and invasiveness, and further evaluate the treatment effect and prognosis of patients.

[Application of multiple nucleotide polymorphism analysis in chimerism detection after allogeneic hematopoietic stem cell transplantation].

Objective: To establish a new method for chimerism analysis after allogeneic hematopoietic stem cell transplantation by using multiple nucleotide polymorphism sequencing (MNPseq) , and to explore its feasibility and superiority. Methods: One hundred MNP fragments were screened and chimeric analysis was performed by high-throughput sequencing technology. The accuracy and sensitivity of the method were verified by simulating chimeric samples and post-transplant samples and comparing them with short tandem repeat (STR) analysis, fusion gene quantitative detection and flow cytometry for minimal residual disease. Results: The accuracy and sensitivity of MNPseq were better than those of STR, in which the sensitivity could reach 0.01%, about 100 times more sensitive than STR. MNPseq could further distinguish 42 STR fully chimeric samples, and after corrected by cutoff value, it was correlated with the quantitative detection of fusion gene. MNPseq could correct false positive of STR caused by the shadow peak, and could be used to detect chimeric samples lacking pre-transplant information from donors and recipients. Conclusion: MNPseq analysis based on high-throughput sequencing is a more accurate and sensitive chimerism detection method, and it solves the problem that chimerism cannot be detected due to the lack of pre-transplant information, which has extremely high clinical application value.