Pathogenesis of chronic lymphocytic leukemia and the development of novel therapeutic strategies

Insights into genetic aberrations and signalling pathway interactions in chronic lymphocytic leukemia: from pathogenesis to treatment strategies

Chronic lymphocytic leukemia (CLL) is prevalent in adults and is characterized by the accumulation of mature B cells in the blood, bone marrow, lymph nodes, and spleens. Recent progress in therapy and the introduction of targeted treatments [inhibitors of Bruton's tyrosine kinase (BTKi) or inhibitor of anti-apoptotic B-cell lymphoma-2 (Bcl-2i) protein (venetoclax)] in place of chemoimmunotherapy have significantly improved the outcomes of patients with CLL. These advancements have shifted the importance of traditional predictive markers, leading to a greater focus on resistance genes and reducing the significance of mutations, such as TP53 and del(17p). Despite the significant progress in CLL treatment, some patients still experience disease relapse. This is due to the substantial heterogeneity of CLL as well as the interconnected genetic resistance mechanisms and pathway adaptive resistance mechanisms to targeted therapies in CLL. Although the knowledge of the pathomechanism of CLL has expanded significantly in recent years, the precise origins of CLL and the interplay between various genetic factors remain incompletely understood, necessitating further research. This review enhances the molecular understanding of CLL by describing how BCR signalling, NF-κB PI3K/AKT, and ROR1 pathways sustain CLL cell survival, proliferation, and resistance to apoptosis. It also presents genetic and pathway-adaptive resistance mechanisms in CLL. Identifying B-cell receptor (BCR) signalling as a pivotal driver of CLL progression, the findings advocate personalized treatment strategies based on molecular profiling, emphasizing the need for further research to unravel the complex interplay between BCR signalling and its associated pathways to improve patient outcomes.

Causal Relationship Between Gut Microbiota and Leukemia: Future Perspectives

The gut microbiota plays a crucial role in maintaining homeostasis in the human gastrointestinal tract. Numerous studies have shown a strong association between the gut microbiota and the emergence and progression of various diseases. Leukemia is one of the most common hematologic malignancies. Although standardized protocols and expert consensus have been developed for routine diagnosis and treatment, limitations remain due to individual differences. Nevertheless, a large number of studies have established a link between the gut microbiota and leukemia, with disturbances in the gut microbiota directly or indirectly affecting the development of leukemia. However, the causal relationship between the two remains unclear, and studying and exploring the causal relationship may open up entirely new avenues and protocols for use in the prevention and/or treatment of leukemia, offering new insights into diagnosis and treatment. In this review, the intricate relationship between the gut microbiota and leukemia is explored in depth, including causal associations, metabolite effects, therapeutic applications, and complications. Based on the characteristics of the gut microbiota, the future applications and prospects of gut microbiota are discussed to provide useful information for clinical treatment of leukemia.

Collision tumor comprised of chronic lymphocytic leukemia and myxopapillary ependymoma

Background

Collision tumors involving the co-occurrence of two morphologically and genomically distinct neoplasms in the same anatomical site are exceptionally rare in the central nervous system (CNS).

Case Description

We report a unique case of a CNS collision tumor comprising chronic lymphocytic leukemia and myxopapillary ependymoma in a 77-year-old male with acute neurological decline. Presumed to represent leukemic infiltration, urgent laminectomy was pursued for tissue diagnosis and spinal cord decompression, revealing the unexpected ependymal component.

Conclusion

This case highlights the diagnostic and therapeutic challenges inherent to managing collision CNS tumors, particularly when one neoplasm is hematological.

GLP and G9a histone methyltransferases as potential therapeutic targets for lymphoid neoplasms

Histone methyltransferases (HMTs) are enzymes that regulate histone methylation and play an important role in controlling transcription by altering the chromatin structure. Aberrant activation of HMTs has been widely reported in certain types of neoplastic cells. Among them, G9a/EHMT2 and GLP/EHMT1 are crucial for H3K9 methylation, and their dysregulation has been associated with tumor initiation and progression in different types of cancer. More recently, it has been shown that G9a and GLP appear to play a critical role in several lymphoid hematologic malignancies. Importantly, the key roles played by both enzymes in various diseases made them attractive targets for drug development. In fact, in recent years, several groups have tried to develop small molecule inhibitors targeting their epigenetic activities as potential anticancer therapeutic tools. In this review, we discuss the physiological role of GLP and G9a, their oncogenic functions in hematologic malignancies of the lymphoid lineage, and the therapeutic potential of epigenetic drugs targeting G9a/GLP for cancer treatment.

StellarPath: Hierarchical-vertical multi-omics classifier synergizes stable markers and interpretable similarity networks for patient profiling

The Patient Similarity Network paradigm implies modeling the similarity between patients based on specific data. The similarity can summarize patients' relationships from high-dimensional data, such as biological omics. The end PSN can undergo un/supervised learning tasks while being strongly interpretable, tailored for precision medicine, and ready to be analyzed with graph-theory methods. However, these benefits are not guaranteed and depend on the granularity of the summarized data, the clarity of the similarity measure, the complexity of the network's topology, and the implemented methods for analysis. To date, no patient classifier fully leverages the paradigm's inherent benefits. PSNs remain complex, unexploited, and meaningless. We present StellarPath, a hierarchical-vertical patient classifier that leverages pathway analysis and patient similarity concepts to find meaningful features for both classes and individuals. StellarPath processes omics data, hierarchically integrates them into pathways, and uses a novel similarity to measure how patients' pathway activity is alike. It selects biologically relevant molecules, pathways, and networks, considering molecule stability and topology. A graph convolutional neural network then predicts unknown patients based on known cases. StellarPath excels in classification performances and computational resources across sixteen datasets. It demonstrates proficiency in inferring the class of new patients described in external independent studies, following its initial training and testing phases on a local dataset. It advances the PSN paradigm and provides new markers, insights, and tools for in-depth patient profiling.

The role of polymorphic cytochrome P450 gene (CYP2B6) in B-chronic lymphocytic leukemia (B-CLL) incidence and outcome among Egyptian patients

Cytochromes P450 (CYPs) play a prominent role in catalyzing phase I xenobiotic biotransformation and account for about 75% of the total metabolism of commercially available drugs, including chemotherapeutics. The gene expression and enzyme activity of CYPs are variable between individuals, which subsequently leads to different patterns of susceptibility to carcinogenesis by genotoxic xenobiotics, as well as differences in the efficacy and toxicity of clinically used drugs. This research aimed to examine the presence of the CYP2B6*9 polymorphism and its possible association with the incidence of B-CLL in Egyptian patients, as well as the clinical outcome after receiving cyclophosphamide chemotherapy. DNA was isolated from whole blood samples of 100 de novo B-CLL cases and also from 100 sex- and age-matched healthy individuals. The presence of the CYP2B6*9 (G516T) polymorphism was examined by PCR-based allele specific amplification (ASA). Patients were further indicated for receiving chemotherapy, and then they were followed up. The CYP2B6*9 variant indicated a statistically significant higher risk of B-CLL under different genetic models, comprising allelic (T-allele vs. G-allele, OR = 4.8, p < 0.001) and dominant (GT + TT vs. GG, OR = 5.4, p < 0.001) models. Following cyclophosphamide chemotherapy, we found that the patients with variant genotypes (GT + TT) were less likely to achieve remission compared to those with the wild-type genotype (GG), with a response percentage of (37.5% vs. 83%, respectively). In conclusion, our findings showed that the CYP2B6*9 (G516T) polymorphism is associated with B-CLL susceptibility among Egyptian patients. This variant greatly affected the clinical outcome and can serve as a good therapeutic marker in predicting response to cyclophosphamide treatment.

A review on expression and regulatory mechanisms of miR-337-3p in cancer

A group of diseases generally referred to as cancer represents a serious threat to people's health all over the world and has a significant negative influence on every aspect of the lives of patients. The development of cancer is influenced by several environmental, genetic, and epigenetic factors. MicroRNAs (miRNAs), a class of non-coding RNAs, can alter the expression of genes involved in cell proliferation, migration, metastasis, and apoptosis, lead to the pathogenesis of cancer. Additionally, several effectors modify miRNAs directly, including methylation, circular RNAs, and long non-coding RNAs (lncRNAs). In this review, we have explained the role of mir-337-3p in the pathways related to the pathogenesis of different cancers. Studying the functional role of miR-337-3p is necessary for detecting novel molecules as tumor markers and discovering novel targets for cancer treatment.Communicated by Ramaswamy H. Sarma.

Global miRNA profiling reveals key molecules that contribute to different chronic lymphocytic leukemia incidences in Asian and Western populations

It has been known for decades that the incidence of chronic lymphocytic leukemia (CLL) is significantly lower in Asia than in Western countries, but the reason responsible for this difference still remains a major knowledge gap. Using GeneChip® miRNA array to analyze the global microRNA expression in B lymphocytes from Asian and Western CLL patients and healthy individuals, we have identified microRNA with CLL-promoting or suppressive functions that are differentially expressed in Asian and Western individuals. In particular, miR-4485 is upregulated in CLL patients of both ethnic groups, and its expression is significantly lower in Asian healthy individuals. Genetic silencing of miR-4485 in CLL cells suppresses leukemia cell growth, whereas ectopic expression of miR-4485 promotes cell proliferation. Mechanistically, miR-4485 exerts its CLL-promoting activity by inhibiting the expression of TGR5 and activating the ERK1/2 pathway. In contrast, miR-138, miR-181a, miR- 181c, miR-181d, and miR-363 with tumor-suppressive function are highly expressed in Asian healthy individuals. Our study suggests that differential expression of several important microRNA with pro- or anti-CLL functions in Asian and Western B lymphocytes likely contributes to the difference in CLL incidence between the two ethnic groups, and that miR-4485 and its downstream molecule TGR5 could be potential therapeutic targets.

Association of CYP1A1 T3801C (rs4646903) variant with the susceptibility and progression of B-chronic lymphocytic Leukemia (B-CLL) in the Egyptian population

BACKGROUND

The frequency of hematological malignancies is increasing universally, and over the last few decades, a significant increase in the incidence of B-chronic lymphocytic leukemia (B-CLL) has been observed. Many studies have revealed the involvement of genetic predisposition along with environmental exposure to genotoxic xenobiotics in the leukemogenesis process of B-CLL. CYP1A1 is a vital member of the cytochromes P450 (CYPs) superfamily, which is involved in pro-carcinogens activation into reactive intermediates during phase I xenobiotic biotransformation.

AIM

This study aimed to determine the possible role of the CYP1A1*2A (T3801C, rs4646903) single nucleotide polymorphism (SNP) as a risk factor for developing B-CLL, as well as the impact of this SNP on the disease progression and the clinical outcome.

PATIENTS AND METHODS

The study was conducted on 100 patients newly diagnosed with B-CLL, and 100 healthy individuals with matched ages and sex, served as the control group. CYP1A1 (T3801C) genotyping of all patient and control samples was performed using the PCR-based Restriction Fragment Length Polymorphism (RFLP-PCR) method. In addition, serum levels of both IL-6 and TNF-α were estimated by the ELISA technique.

RESULTS

Higher frequencies of the heterozygous carrier (TC) and homozygous variant (CC) genotypes of the CYP1A1 (T3801C) variant were observed in B-CLL patients compared to the controls (P < 0.001 for both). The frequencies of the CYP1A1 (T3801C) variant indicated a significant elevated risk of B-CLL under various genetic models, including allelic (OR = 8.8, P < 0.001) and dominant (OR = 9.3, P < 0.001) models. In addition, the median IL-6 level was significantly higher in patients with (TC) and (CC) genotypes than in patients with (TT) genotype (P = 0.001 and P < 0.001, respectively). Also, the median TNF-α level was significantly higher in patients with (TC) and (CC) genotypes than in patients with (TT) genotype (P < 0.001 for both).

CONCLUSION

Our results showed that the CYP1A1*2A (T3801C, rs4646903) SNP increases the susceptibility to B-CLL incidence and is associated with poor disease progression.

Prognosis of a Chinese patient with chronic lymphocytic leukemia who acquired a TP53 mutation following treatment with a BTK inhibitor

Chronic lymphocytic leukemia (CLL) is a common type of adult leukemia that occurs in Western countries, and its incidence has gradually increased in China in recent years. The characteristics of CLL are highly heterogeneous. Despite promising response rates achieved with targeted therapy, new targets still need to be expanded due to the heterogeneous of disease. Bruton's tyrosine kinase inhibitor (BTKi) has been used in the treatment of TP53 mutation. In this report, we present a case with myeloid differentiation primary response 88 (MYD88) mutation who developed a TP53 mutation after application of BTKi. Here, the patient was CLL unmutated (U-CLL) with MYD88 (L265P) mutation before initial treatment. After traditional treatment, the effect was not good, and BTKi was used for treatment, then TP53 mutation appeared. It is well known that immunoglobulin heavy chain unmutated (IGHV-U) and TP53 mutation in CLL indicate poor prognosis. The case suggests that whenever TP53 mutation occurs, BTKi is the best choice. This result is considered to be related to signal pathways. We aim to add to the collective knowledge by highlighting this rare cases of CLL with MYD88 (L265P) mutation in an Asian patient.

Significance of PPARA as a Treatment Target for Chronic Lymphocytic Leukemia

Peroxisome proliferator-activated receptor alpha (PPARA) has been suggested as a therapeutic target for chronic lymphocytic leukemia (CLL). However, the underlying molecular mechanism remains largely unclear. In this study, we analyzed DNA next-generation sequencing (NGS) data and clinical information from 86 CLL patients to identify gene markers related to treatment-free survival (TFS) length. We then constructed a genetic network that includes CLL promoters, treatment targets, and TFS-related marker genes. To assess the significance of PPARA within the network, we utilized degree centrality (DC) and pathway enrichment score (EScore). Clinical and NGS data revealed 10 TFS length-related gene markers, including RPS15, FOXO1, FBXW7, KMT2A, NOTCH1, GNA12, EGR2, GNA13, KDM6A, and ATM. Through literature data mining, 83 genes were identified as CLL upstream promoters and treatment targets. Among them, PPARA exhibited a stronger connection to CLL and TFS-related gene markers, as evidenced by its ranking at No. 13 based on DC, compared to most of the other promoters (>84%). Additionally, PPARA co-functions with 70 out of 92 in-network genes in various functional pathways/gene groups related to CLL pathology, such as regulation of cell adhesion, inflammation, reactive oxygen species, and cell differentiation. Based on our findings, PPARA is considered one of the critical genes within a large genetic network that influences the prognosis and TFS of CLL through multiple pathogenic pathways.

B cell M-CLL clones retain selection against replacement mutations in their immunoglobulin gene framework regions

Introduction

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia, accounting for 30–40% of all adult leukemias. The dynamics of B-lymphocyte CLL clones with mutated immunoglobulin heavy chain variable region (IgHV) genes in their tumor (M-CLL) can be studied using mutational lineage trees.

Methods

Here, we used lineage tree-based analyses of somatic hypermutation (SHM) and selection in M-CLL clones, comparing the dominant (presumably malignant) clones of 15 CLL patients to their non-dominant (presumably normal) B cell clones, and to those of healthy control repertoires. This type of analysis, which was never previously published in CLL, yielded the following novel insights.

Results

CLL dominant clones undergo – or retain – more replacement mutations that alter amino acid properties such as charge or hydropathy. Although, as expected, CLL dominant clones undergo weaker selection for replacement mutations in the complementarity determining regions (CDRs) and against replacement mutations in the framework regions (FWRs) than non-dominant clones in the same patients or normal B cell clones in healthy controls, they surprisingly retain some of the latter selection in their FWRs. Finally, using machine learning, we show that even the non-dominant clones in CLL patients differ from healthy control clones in various features, most notably their expression of higher fractions of transition mutations.

Discussion

Overall, CLL seems to be characterized by significant loosening – but not a complete loss – of the selection forces operating on B cell clones, and possibly also by changes in SHM mechanisms.

PI3k Inhibitors in NHL and CLL: An Unfulfilled Promise

Phosphatidylinositol 3-kinases (PI3Ks) are a family of intracellular signal transducer enzymes that can attach a phosphate group to the 3'-hydroxyl of the inositol moiety of membrane-embedded phosphatidylinositol (PI). PI3Ks have been shown to play important roles in cell proliferation, growth, survival, motility, and metabolism. Nonetheless, the PI3K pathway has also shown to be overactivated in several tumors, particularly B-cell malignancies. In recent years, the PI3K signaling pathway has become the major focus of substantial drug discovery and development efforts. Selective (PI3K) inhibitors have been approved for the treatment of chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), and indolent non-Hodgkin lymphomas (iNHL), such as follicular lymphoma and marginal-zone lymphoma. Four selective PI3K inhibitors have received accelerated FDA approvals for the treatment of patients with relapsed/refractory (R/R) CLL and/or iNHL based mainly on single-arm Phase II studies: Idelalisib (PI3K-δ inhibitor), copanlisib (dual PI3K-α and PI3K-δ inhibitor), duvelisib (dual PI3K-γ and PI3K-δ inhibitor), and umbralisib (dual PI3Kδ and CK1ε inhibitor). Conversely, recent interim results of randomized control trials (RCTs) involving some of these agents, showed a worrisome trend of decrease in overall survival (OS), and an increase in fatal and severe adverse effects, in comparison with patients in the control arms. Consequently, the class of PI3K inhibitors came under scrutiny, with an FDA expert panel voting on April 21, 2022, recommending that future FDA approvals of PI3K inhibitors be supported by randomized data, rather than single-arm data only, and further discontinuing the use of almost all the PI3K inhibitors in hematologic malignancies. As we believe further research is needed to help potentialize PI3K inhibitors by improving their safety profiles, this mini-review aims at revisiting the clinical successes, the failures, and the promising aspect of this class of drugs, while presenting possible ways that could benefit its successful development.

Competing endogenous RNA networks related to prognosis in chronic lymphocytic leukemia: comprehensive analyses and construction of a novel risk score model

BACKGROUND

Chronic lymphocytic leukemia (CLL) is a heterogeneous B-cell malignancy that lacks specific biomarkers and drug targets. Competing endogenous RNAs (ceRNAs) play vital roles in oncogenesis and tumor progression by sponging microRNAs (miRNAs). Nevertheless, the regulatory mechanisms of survival-related ceRNA networks in CLL remain to be uncovered.

METHODS

We included 865 de novo CLL patients to investigate RNA expression profiles and Illumina sequencing was performed on four CLL patients, two CLL cell lines and six healthy donors in our center. According to univariate Cox regression, LASSO regression as well as multivariate Cox regression analyses, we established a novel risk score model in CLL patients. Immune signatures were compared between the low- and high-risk groups with CIBERSORT and ESTIMATE program. Afterwards, we analyzed the relationship between differentially expressed miRNAs (DEmiRNAs) and IGHV mutational status, p53 mutation status and del17p. Based on the survival analyses and differentially expressed RNAs with targeting relationships, the lncRNA/circRNA-miRNA-mRNA ceRNA networks were constructed. In addition, the circRNA circ_0002078/miR-185-3p/TCF7L1 axis was verified and their interrelations were delineated by dual-luciferase reporter gene assay.

RESULTS

Totally, 57 differentially expressed mRNAs (DEmRNAs) and 335 DEmiRNAs were identified between CLL patient specimens and normal B cells. A novel risk score model consisting of HTN3, IL3RA and NCK1 was established and validated. The concordance indexes of the model were 0.825, 0.719 and 0.773 in the training, test and total sets, respectively. The high-risk group was related to del(13q14) as well as shorter overall survival (OS). Moreover, we identified DEmiRNAs that related to cytogenetic abnormality of CLL patients, which revealed that miR-324-3p was associated with IGHV mutation, p53 mutation and del17p. The survival-related lncRNA/circRNA-miRNA-mRNA ceRNA networks were constructed to further facilitate the development of potential predictive biomarkers. Besides, the expression of circ_0002078 and TCF7L1 were significantly elevated and miR-185-3p was obviously decreased in CLL patients. Circ_0002078 regulated TCF7L1 expression by competing with TCF7L1 for miR-185-3p.

CONCLUSIONS

The comprehensive analyses of RNA expression profiles provide pioneering insights into the molecular mechanisms of CLL. The novel risk score model and survival-related ceRNA networks promote the development of prognostic biomarkers and potential therapeutic vulnerabilities for CLL.

Dysregulation of Small Nucleolar RNAs in B-Cell Malignancies

Small nucleolar RNAs (snoRNAs) are responsible for post-transcriptional modification of ribosomal RNAs, transfer RNAs and small nuclear RNAs, and thereby have important regulatory functions in mRNA splicing and protein translation. Several studies have shown that snoRNAs are dysregulated in human cancer and may play a role in cancer initiation and progression. In this review, we focus on the role of snoRNAs in normal and malignant B-cell development. SnoRNA activity appears to be essential for normal B-cell differentiation and dysregulated expression of sno-RNAs is determined in B-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, B-cell non-Hodgkin’s lymphoma, and plasma cell neoplasms. SnoRNA expression is associated with cytogenetic/molecular subgroups and clinical outcome in patients with B-cell malignancies. Translocations involving snoRNAs have been described as well. Here, we discuss the different aspects of snoRNAs in B-cell malignancies and report on their role in oncogenic transformation, which may be useful for the development of novel diagnostic biomarkers or therapeutic targets.

Unmutated IGHV1-69 CLL Clone Displays a Distinct Gene Expression Profile by a Comparative qRT-PCR Assay

Chronic Lymphocytic Leukemia (CLL) is a heterogeneous disease characterized by variable clinical courses among different patients. This notion was supported by the possible coexistence of two or more independent CLL clones within the same patients, identified by the characterization of the B cell receptor immunoglobulin (BcR IG) idiotypic sequence. By using the antigen-binding site of the BcR IG as bait, the identification and isolation of aggressive and drug-resistance leukemic B-cell clones could allow a deeper biological and molecular investigation. Indeed, by the screening of phage display libraries, we previously selected a peptide binder of the idiotypic region of CLL BCR IGs expressing the unmutated rearrangement IGHV1-69 and used it as a probe to perform a peptide-based cell sorting by flow cytometry in peripheral blood samples from patients with CLL. Since the IGHV1-69 clones persisted during the follow-up time in both patients, we explored the possibility of these clones having acquired an evolutive advantage compared to the other coexisting clones in terms of a higher expression of genes involved in the survival and apoptosis escape processes. To this end, we studied the expression patterns of a panel of genes involved in apoptosis regulation and in NF-kB-dependent pro-survival signals by comparative qRT-PCR assays. According to the results, IGHV1-69 clones showed a higher expression of pro-survival and anti-apoptotic genes as compared to the other CLL clones with different immunogenetic characteristics. Moreover, these IGHV1-69 clones did not carry any characteristic genetic lesions, indicating the relevance of our approach in performing a comprehensive molecular characterization of single tumor clones, as well as for designing new personalized therapeutic approaches for the most aggressive and persistent tumor clones.

Mitochondria and Their Relationship with Common Genetic Abnormalities in Hematologic Malignancies

Hematologic malignancies are known to be associated with numerous cytogenetic and molecular genetic changes. In addition to morphology, immunophenotype, cytochemistry and clinical characteristics, these genetic alterations are typically required to diagnose myeloid, lymphoid, and plasma cell neoplasms. According to the current World Health Organization (WHO) Classification of Tumors of Hematopoietic and Lymphoid Tissues, numerous genetic changes are highlighted, often defining a distinct subtype of a disease, or providing prognostic information. This review highlights how these molecular changes can alter mitochondrial bioenergetics, cell death pathways, mitochondrial dynamics and potentially be related to mitochondrial genetic changes. A better understanding of these processes emphasizes potential novel therapies.

13q14 Deletion and Its Effect on Prognosis of Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia affecting adults. CLL results due to uncontrolled accumulation of B lymphocytes in the body with the clinical spectrum ranging from comparatively benign disease to an aggressive form. The disease pathogenesis lies in molecular genetics, the most common alteration being the deletion in the long arm of chromosome 13, at position 14 (13q14) region. This deletion leads to the loss of important microRNAs which are involved in maintaining the critical balance of the apoptosis mechanism of cell death of B lymphocytes. As such, the imbalance contributes towards B cells' immortality and, thus, CLL arises. This significant 13q14 deletion contributes to CLL's pathogenesis and paves the way for CLL treatment, hence affecting the prognosis of the affected patients.

Furthermore, the size of deletion of the long arm of chromosome 13 (13q) has a remarkable effect on its prognosis and therapeutic intervention. The minimal deleted region (MDR)/small deletion or long 13q loss/mutation, and biallelic 13q deletion or monoallelic 13q deletion are commonly seen. 13q14 deletion is an initiating defect targeting tumor suppressor gene locus deleted in lymphocytic leukemia 2 (DLEU2))/microRNA15A (MIR15A)/microRNA 16-1 (MIR 16-1). Regarding CLL treatment, conventional therapy with alkylating agents has been used for a long time, which reported low- to non-existent complete remission rates and adverse events after prolonged use. Moreover, research into the 13q14 deletion has also provided new insights into the molecular genetics and pathways that interact in such a way, making it possible to transform healthy cells into malignant cells in an entirely new fashion with a complete disregard to its original form, resulting in CLL.