Expression of genes potentially involved in loss of response in patients with chronic myeloid leukemia.

Chronic Myeloid Leukemia (CML) is a hematological malignancy characterized by the presence of the BCR::ABL1 fusion gene, which leads to uncontrolled cell growth and survival. Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of CML, but a significant proportion of patients develop resistance or lose response to these drugs. Understanding the molecular mechanisms underlying treatment response and resistance is crucial for improving patient outcomes. This study aimed to analyze the expression patterns of genes involved in treatment response and resistance in CML patients receiving TKI therapy. The expression levels of MET, FOXO3, p15, p16, HCK, and FYN genes were examined in CML patients and compared to healthy donors. Gene expression levels were compared between optimal responders (OR) and resistant patients (R) vs. healthy donors (HD). The MET and FOXO3 OR group showed significant differences compared with the HD, (p < 0.0001) and (p = 0.0003), respectively. p15 expression showed significant differences between OR and HD groups (p = 0.0078), while no significant differences were found in p16 expression between the HD groups. FYN showed a statistically significant difference between R vs. HD (p = 0.0157). The results of HCK expression analysis revealed significant differences between OR and HD (p = 0.0041) and between R and HD (p = 0.0026). When we analyzed OR patients with undetectable BCR::ABL1 transcripts, a greater expression of HCK was observed in the R group. These findings suggest that monitoring the expression levels of MET and FOXO3 genes could be valuable in predicting treatment response and relapse in CML patients. Our study provides important insights into the potential use of gene expression analysis as a tool for predicting treatment response and guiding treatment decisions in CML patients. This knowledge may ultimately contribute to the development of personalized treatment strategies to improve patient outcomes in CML.

Asymptomatic dengue virus cases in misiones, Argentina: a seroprevalence study in the university population.

Dengue infection may be asymptomatic and may produce the typical symptoms of a benign illness or serious hemorrhagic and often fatal symptoms. Asymptomatic cases are statistically relevant and quite variable depending on the geographic area under study. However, there are no reports of asymptomatic population infected by the dengue virus in Misiones. In this study, 288 samples were analyzed, and the IgG anti dengue antibodies detected accounted for 6.6% of cases, while 89% corresponded to individuals who lived with people diagnosed or suspected of having contracted dengue, p= <0.001.

GSTM1 and GSTP1, but not GSTT1 genetic polymorphisms are associated with chronic myeloid leukemia risk and treatment response.

BACKGROUND: Chronic myeloid leukemia (CML) is associated to the BCR-ABL1 oncogene and can successfully be treated with tyrosine kinase inhibitors (TKIs). However, it remains still under investigation which molecular factors may influence CML risk or varying responses to TKIs. The aim of this study was to assess the role of Glutathione-S-transferases (GSTs) genetic polymorphisms in CML susceptibility and TKI clinical outcome. MATERIALS: Deletion polymorphisms in GSTM1 and GSTT1 genes and the single nucleotide polymorphism in GSTP1 c.319A>G (rs1695; p.105Ile>Val) were genotyped by PCR methods in 141 CML treated patients and 141 sex- and age-matched healthy individuals. RESULTS: Individual analysis of each GST gene showed no association with CML risk. A trend toward significance (p=0.07) for a recessive model was found for GSTP1 (OR: 2.04; CI: 0.94-4.4). However, the combined analysis showed that GSTM1-null/GSTP1-GG as well as GSTT1-null/GSTP1-GG were associated with CML development (p=0.03; OR: 3.54 CI: 1.2-14.57; p=0.05; OR: 12.65; CI: 1.17-21.5). The relationship with treatment outcome showed that the presence of GSTM1 gene was significantly linked with an inferior rate of major molecular response (p=0.048) and poor event free-survival (EFS) (p=0.02). Furthermore, a group of patients with GSTP1-GG genotype were significantly associated with reduced EFS comparing to those carrying other GSTP1 genotypes (p=0.049). GSTP1-GG genotypes had short time to treatment failure in a group of patients unresponsive to TKIs comparing to other GSTP1 genotypes (p=0.03). CONCLUSIONS: This study highlights the significance of GSTM1 and GSTP1 polymorphisms on CML susceptibility and response to TKIs in the Argentinean population.

TP53 codon 72 polymorphism predicts chronic myeloid leukemia susceptibility and treatment outcome.

BCR-ABL1 gene is a key molecular marker of chronic myeloid leukemia (CML), but it is still unclear which molecular factors may influence CML risk or lead to variable responses to tyrosine kinase inhibitors (TKIs). The aim of this study was to investigate the impact of TP53 c.213 G>C(Arg72Pro; rs1042522) polymorphism on CML risk and its correlation with clinical outcome. Peripheral blood samples from 141 treated CML patients and 141 sex- and age-matched healthy individuals were genotyped by PCR-RFLP. Standard genetic models for disease penetrance were evaluated by logistic regression analysis and Kaplan-Meier method was performed to estimate survival curves. Our study suggests that TP53 c.213 G>C polymorphism may be involved in CML development considering a recessive model (p=0.01; OR: 0.19; CI: 0.06-0.68). In addition, a non-homogenous distribution was found for this polymorphism in males and patients youngers than 50years (p=0.02). According to clinical response, TP53-GG genotype was associated with higher levels of BCR-ABL1 transcripts (p=0.04) and shorter event free survival (p=0.04). Moreover, a trend toward significance was found for failure free survival (p=0.06) and time to imatinib failure (p=0.08). In conclusion, our data suggest that a;TP53 c.213 G>C may be a potential biomarker of CML susceptibility and clinical outcome.

Clinical activity of ponatinib in one patient with chronic myeloid leukemia in chronic phase with e19a2 transcript and T315I mutation.

BACKGROUND: Chronic myeloid leukemia (CML) is a hematological disorder that in rare cases, mainly in CML neutrophilic, presents the e19a2 rearrangement. The encoded product is a 230-KDa protein. Despite the remarkable responses to treatment of most patients, a small but significant fraction of them develop clinical resistance to the tyrosine kinase inhibitors (TKIs). The most common mechanism of resistance is point mutations in the ABL1 kinase domain. The recently approved third-generation TKI ponatinib demonstrated remarkable activity in patients with multi-TKI-resistant disease. Particularly impressive was its efficacy in patients with T315I mutation that is resistant to all other TKIs. METHODS: Qualitative PCR was carried out by multiplex approach. Relative transcripts quantification was performed by one-step real-time PCR, with a specific Taqman probe and primers for the e19a2 rearrangement. We carried out a mutational screening by high-resolution melting, and the mutation was identified by Sanger method. The mutation burden was quantified by quantitative PCR using allele-specific primers. RESULTS: In a patient with CML, we identified a PCR product corresponding to e19a2 rearrangement harboring T315I mutation. At the time of mutational analysis, during dasatinib treatment, the T315I clone was 100% and the quantification of BCR-ABL1 was 18%. After ponatinib therapy, the T315I mutation burden decreased down to undetectable levels and the BCR-ABL1 transcripts showed a very low value (0.011%). CONCLUSIONS: Here, we report the hematological, cytogenetic, and molecular response of a patient with refractory CML in chronic phase with e19a2 transcripts, carrying T315I mutation that was successfully treated with ponatinib.

CAMKIIγ, HSP70 and HSP90 transcripts are differentially expressed in chronic myeloid leukemia cells from patients with resistant mutated disease.

Patients with chronic myeloid leukemia (CML) can develop disease resistance to tyrosine kinase inhibitor (TKI) therapy, which is mainly attributable to the presence of point mutations in the tyrosine kinase domain of BCR-ABL1. In order to examine suitable markers to monitor treatment efficacy, we investigated transcript expression profiles of genes known to be involved in myeloid cell proliferation, such as CAMKIIγ and KI67, and in protein stability and ultimately cell survival under physiological and stress conditions, such as heat shock proteins HSP70 and HSP90. We studied 101 patients with CML in different stages of disease and with different responses to TKI treatment. The results of quantitative real-time polymerase chain reaction (qPCR) analyses showed that the expression levels of CAMKIIγ, KI67, HSP70 and HSP90 genes were up-regulated at diagnosis, and in cases with signs of treatment resistance both in chronic and advanced phases (accelerated and blastic phases) with respect to chronic phase in remission and healthy donors. When only 56 resistant cases, 31 with mutations (MT) and 25 without mutations (WT), in the BCR-ABL1 tyrosine kinase domain were considered, the transcript expression profile showed an unexpected significant increase in CAMKIIγ and HSP70, and a significant decrease in HSP90 in MT versus WT cases. This differential transcript expression prompted us to design an expression score, log(CAMKIIγ × HSP70/HSP90), which can be used to provide rapid screening to discriminate the presence or absence of mutations in resistant cells and to monitor TKI treatment efficacy in patients with CML.

Expression of LYN and PTEN genes in chronic myeloid leukemia and their importance in therapeutic strategy.

Tyrosine kinase inhibitors (TKIs), imatinib, nilotinib and dasatinib, are the current treatment of chronic myeloid leukemia (CML). BCR-ABL1 point mutations are the principal cause of resistance to treatment; however other mechanisms could be involved in failure to TKI therapy. LYN is a src kinase protein that regulates survival and responsiveness of tumor cells by a BCR-ABL1 independent mechanism. PTEN tumor suppressor gene is downregulated by BCR-ABL1 in CML stem cells and its deletion is associated with acceleration of disease. In this study we evaluated the expression of LYN, PTEN and the ratio of both genes in 40 healthy donors (HD) and in 139 CML patients; 88 of them resistant to TKI in different phases of disease and 51 in chronic phase classified as optimal responders (OR) to TKI [40 treated with imatinib or nilotinib (OR-IN) and 11 treated with dasatinib (OR-D) therapy]. When we analyzed the gene expression values of LYN, an increase was observed only in advanced stages of the disease, however, when we analyzed the ratio between LYN and PTEN genes, the group of resistant patients in chronic phase in imatinib or nilotinib treatment (CP-IN) also showed a significant increase. Resistant patients treated with dasatinib, a src kinase inhibitor, presented a similar ratio to the observed in HD. In addition, the LYN/PTEN ratio and the LYN expression showed a direct significant correlation with BCR-ABL1 transcript levels in unmutated resistant patients treated with non-src kinase inhibitors. We were able to identify 8/35 (23%) of cases in CP-IN and 4/12 (33%) in accelerated phase and blast phase (AP/BC-IN), in which resistance could be associated with an increase in the ratio of the LYN/PTEN. Our data suggest that the LYN/PTEN expression ratio may be a sensitive monitor of disease progression in unmutated CML patients under imatinib or nilotinib treatment. This ratio could detect cases when resistance is related to altered LYN expression, suggesting that the treatment change to a src kinase inhibitor would be most suitable to overcome resistance.

Early detection and quantification of mutations in the tyrosine kinase domain of chimerical BCR-ABL1 gene combining high-resolution melting analysis and mutant-allele specific quantitative polymerase chain reaction.

BCR-ABL1 point mutations are the most common cause of resistance in patients with chronic myeloid leukemia (CML) who fail or lose response to tyrosine kinase inhibitors. We have developed a rapid method to screen BCR-ABL1 mutations by high resolution melting (HRM). We designed a strategy based on amplification refractory mutational system-quantitative polymerase chain reaction (ARMS-qPCR) to identify and quantify several clinically relevant mutations. From 856 patients with CML studied during 2 years in our laboratory, we selected 32 who showed persistent levels of BCR-ABL1 transcripts (>0.1%) in at least two consecutive studies. Using our strategy, we identified mutations in 11/32 cases (34.4%), while only two of them (6.2%) were detectable by sequencing. Furthermore, we were able to estimate the timing and dynamics of mutated clones, evaluating retrospective samples from the same patient. In cases with lack or loss of molecular response this analysis might be useful for designing early therapeutic strategies.