The interplay between telomeric complex members and BCR::ABL1 oncogenic tyrosine kinase in the maintenance of telomere length in chronic myeloid leukemia

PURPOSE

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by recurrent genetic aberration in leukemic stem cells, namely Philadelphia chromosome caused by reciprocal translocation t(9;22)(q34;q11). In our study, we analyzed the telomeric complex expression and function in the molecular pathogenesis of CML.

METHODS

We employed CD34+ primary leukemic cells, comprising both leukemic stem and progenitor cell populations, isolated from peripheral blood or bone marrow of CML patients in chronic and blastic phase to analyze the telomere length and telomeric-associated proteins.

RESULTS

The reduction in telomere length during disease progression was correlated with increased expression of BCR::ABL1 transcript and the dynamic changes were neither associated with the enzymatic activity of telomerase nor with gene copy number and expression of telomerase subunits. Increased expression of BCR::ABL1 was positively correlated with expression of TRF2, RAP1, TPP1, DKC1, TNKS1, and TNKS2 genes.

CONCLUSIONS

The dynamics of telomere length changes in CD34+ CML cells is dependent on the expression level of BCR::ABL, which promotes the expression of certain shelterins including RAP1 and TRF2, as well as TNKS, and TNKS2, and results in telomere shortening regardless of telomerase activity. Our results may allow better understanding of the mechanisms responsible for the genomic instability of leukemic cells and CML progression.

Epithelial Cells of Deep Infiltrating Endometriosis Harbor Mutations in Cancer Driver Genes

Endometriosis is an inflammatory condition manifested by the presence of endometrial-like tissue outside of the uterine cavity. The most common clinical presentations of endometriosis are dysmenorrhea, infertility, and severe pelvic pain. Few hypotheses attempt to explain the pathogenesis of endometriosis; however, none of the theories have been fully confirmed or considered universal. We examined somatic mutations in eutopic endometrium samples, deep endometriotic nodules and peripheral blood from 13 women with deep endometriosis of the rectovaginal space. Somatic variants were identified in laser microdissected samples using next-generation sequencing. A custom panel of 1296 cancer-related genes was employed, and selected genes representing cancer drivers and non-drivers for endometrial and ovarian cancer were thoroughly investigated. All 59 detected somatic variants were of low mutated allele frequency (<10%). In deep ectopic lesions, detected variants were significantly more often located in cancer driver genes, whereas in eutopic endometrium, there was no such distribution. Our results converge with other reports, where cancer-related mutations were found in endometriosis without cancer, particularly recurrent KRAS mutations. Genetic alterations located in ectopic endometriotic nodules could contribute to their formation; nevertheless, to better understand the pathogenesis of this disease, more research in this area must be performed.

Predictive significance of selected gene mutations in relapsed and refractory chronic lymphocytic leukemia patients treated with ibrutinib

BACKGROUND

Ibrutinib, an inhibitor of the Bruton's kinase (BTK), is characterized by high efficacy in the therapy of patients with relapsed and refractory chronic lymphocytic leukemia (RR-CLL).

AIMS

To analyze the potential significance of the mutational status of selected 30 genes on the disease outcome in 45 patients with RR-CLL using custom-made gene panel and sequencing on Illumina MiSeq FGx platform.

RESULTS

The highest rate of mutations was observed in TP53 (n = 18; 40.0%), NOTCH1 (n = 13; 28.8%), SF3B1 (n = 11; 24.4%), ATM (n = 7; 15.6%), MED12 (n = 6, 13.3%), CHD2 (n = 5; 11.1%), XPO1 (n = 5; 11.1%), NFKBIE (n = 5; 11.1%), BIRC3 (n = 4; 8.9%), SPEN (n = 4; 8.9%), POT1 (n = 4; 8.9%), EGR2 (n = 3; 6.7%), and RPS15 (n = 3; 6.7%). With a median observation time of 45.9 months, the median progression-free survival (PFS) and overall survival (OS) were not reached. The 36-month estimated rate of PFS and OS were 64% and 68.2%, respectively. The overall response rate was noted in 23 patients (51.1%), while twenty (44.4%) patients achieved stability. Progression was noted in 2 (4.5%) cases. Analyzed molecular factors had no impact on PFS and OS.

CONCLUSION

Despite accumulation of several poor prognostic factors in our real-life cohort of heavily pretreated patients with CLL, ibrutinib treatment showed long-term clinical benefit.