Chronic Myeloid Leukemia Mutations: Pathogenesis Insights
Intro
Chronic myeloid leukemia (CML) is a complex disease characterized by the uncontrolled proliferation of myeloid cells in the bone marrow and blood. The primary driver of this malignancy is a specific mutation known as the Philadelphia chromosome, which results from a translocation between chromosomes 9 and 22. This genetic alteration leads to the creation of the BCR-ABL fusion gene, actively contributing to the pathogenesis of CML.
Understanding the mutations associated with CML is crucial for elucidating the disease's mechanisms and developing targeted therapies. Given the evolving landscape of CML treatment, a comprehensive analysis of these mutations provides insight into therapeutic developments and patient management. This article will dive into the methodologies, discuss findings from recent research, and explore the implications of these mutations for diagnosis and treatment.
Methodologies
Description of Research Techniques
Research on CML mutations typically employs a combination of cytogenetic analysis and next-generation sequencing (NGS). Cytogenetic techniques, particularly fluorescence in situ hybridization (FISH), are fundamental for detecting the Philadelphia chromosome. These methods facilitate the visualization of chromosomal abnormalities in individual cells.
Next-generation sequencing plays a crucial role in identifying additional mutations that may arise over the course of the disease. Techniques like targeted sequencing and whole-exome sequencing enable the comprehensive examination of genes involved in CML, thus offering insights into the mutational landscape of the disease. By integrating these techniques, researchers can assess not only the presence of the BCR-ABL fusion gene but also the landscape of other co-occurring mutations that influence disease progression.
Tools and Technologies Used
The array of technologies employed in CML mutation research includes:
- Fluorescence In Situ Hybridization (FISH): Used to detect the Philadelphia chromosome in individual cells.
- Next Generation Sequencing (NGS): A method for detailed analysis of mutational profiles.
- Polymerase Chain Reaction (PCR): Essential for amplifying specific gene regions for analysis.
- Bioinformatics Tools: Software designed to analyze large genomic datasets and interpret results effectively.
By utilizing these advanced tools, researchers can enhance the understanding of CML, paving the way for more effective diagnostic and treatment strategies.
Discussion
Comparison with Previous Research
Recent studies emphasize the importance of identifying secondary mutations in the TKI-resistant patients. Previous research primarily focused on the BCR-ABL mutation alone. The shift toward a comprehensive analysis heralds a new understanding of CML that moves beyond traditional models. For instance, mutations in the ASXL1 and TET2 genes are increasingly recognized for their role in disease progression and resistance to treatment.
Theoretical Implications
The implications of these findings are profound. The existence of multiple mutations within the same patient population raises questions about treatment protocols. Personalized medicine approaches may become more central, shifting focus from a one-size-fits-all strategy to tailored therapies matching individual mutational profiles. Moreover, understanding the dynamics of these mutations will be critical in the development of new therapeutic agents aimed at overcoming resistance and improving patient outcomes.
In summary, the ongoing research on CML mutations sheds light on the complexities of the disease and the need for nuanced approaches in treatment. As this field progresses, it is essential to remain updated with the latest findings, ensuring optimal care for patients affected by this challenging condition.
Understanding Chronic Myeloid Leukemia
Chronic Myeloid Leukemia (CML) is a multifaceted and progressive disorder that primarily affects the blood and bone marrow. The understanding of this disease is crucial as it lays the groundwork for exploring its genetic underpinnings and the complex mutations responsible for its pathogenesis. By dissecting the elements pertaining to CML, we can appreciate not only how it develops but also how it could be approached in terms of diagnosis and treatment. This makes the understanding of CML vital for medical professionals and researchers who aim to devise strategic interventions and improve patient outcomes.
Definition of Chronic Myeloid Leukemia
Chronic Myeloid Leukemia is a type of cancer that occurs when there is an abnormal proliferation of myeloid cells in the bone marrow and blood. It is characterized mainly by the presence of an abnormal chromosome known as the Philadelphia chromosome, resulting from a genetic translocation. This alteration leads to the formation of the BCR-ABL fusion gene, which produces a tyrosine kinase that promotes cell division and inhibits apoptosis, contributing to the accumulation of these malignant cells. "CML typically progresses through phases, with the potential to transform into a more aggressive form called blastic crisis if not adequately treated."
Epidemiology of
The epidemiological landscape of Chronic Myeloid Leukemia reveals significant insights into its prevalence and demographic distribution. CML accounts for approximately 15% of all adult leukemias, with an annual incidence rate of around 1–2 cases per 100,000 individuals in the population. The disease is much more common in adults, particularly between the ages of 50 and 70. It has a slight male predominance, with men being diagnosed more frequently than women. Furthermore, lifestyle factors, environmental exposures, and genetic predispositions may influence the risk of developing CML.
Research shows that certain regions, particularly those with high pollution levels or specific occupational hazards, may experience higher incidence rates. This aspect emphasizes the importance of targeted studies in understanding geographical discrepancies in CML cases.
In summary, grasping the definition and epidemiology of Chronic Myeloid Leukemia is not merely an academic exercise. It has practical implications for diagnostics, therapeutic strategies, and future research initiatives aimed at combating this challenging blood malignancy.
Molecular Pathogenesis of
Understanding the molecular pathogenesis of Chronic Myeloid Leukemia (CML) is critical in unraveling how mutations contribute to disease development and progression. This section discusses essential elements like genetic mutations and cellular functions that interplay in the etiology of CML. The insights gained from this exploration will provide a framework for better diagnosis, treatment strategies, and management of the disease.
The Role of Hematopoietic Stem Cells
Hematopoietic stem cells (HSCs) are pivotal in the context of CML. These cells are responsible for producing blood cells and are normally found in the bone marrow. In CML, mutations in these stem cells cause them to proliferate abnormally, leading to the overproduction of myeloid lineage cells. The transformation of HSCs into malignant cells is a multifaceted process.
The chronic nature of CML is largely attributed to the capacity of HSCs to self-renew, leading to a persistent pool of mutated cells. This self-renewal ability allows the leukemic cells to evade normal apoptotic signals. Understanding the biology of HSCs and their role in CML opens the door to targeted therapeutic interventions that can lead to better patient outcomes.
Genetic Mutations in
Genetic mutations in CML are the key drivers of the disease's pathogenesis. These mutations not only elucidate the mechanisms behind the disease but also provide valuable information for treatment options.
BCR-ABL Fusion Gene
The BCR-ABL fusion gene is a hallmark of CML, resulting from a translocation between chromosomes 9 and 22. This genetic alteration leads to the formation of a hybrid protein with constitutive tyrosine kinase activity. This aberrant activity drives uncontrolled proliferation of myeloid cells.
What makes the BCR-ABL fusion gene a fundamental aspect of CML is its role as a target for specific therapy. Tyrosine kinase inhibitors such as Imatinib have emerged as the standard treatment due to their ability to directly inhibit the activity of the BCR-ABL protein. However, the presence of this fusion gene also indicates a potential challenge in the development of drug resistance.
Secondary Mutations
Secondary mutations develop after the initial BCR-ABL fusion and can confer resistance to treatment. These mutations can occur in various regions of the BCR-ABL gene, impacting the binding of tyrosine kinase inhibitors and complicating treatment options.
The identification of secondary mutations is critical for adjusting therapeutic strategies. Monitoring these mutations can help clinicians predict treatment response and outcomes, allowing for personalization of therapy.
Mutational Landscape
The mutational landscape of CML encompasses an array of genetic changes. Analyzing these mutations offers insights into disease progression and potential therapeutic vulnerabilities. The complexity of the mutational landscape is significant for understanding why patients respond variably to therapies.
Notably, distinctions in the mutational landscape can guide novel treatment approaches. Researchers continue to investigate how these diverse mutations interact and their implications for future targeted therapies.
The interplay between core mutations and treatment remains an active area of research, reflecting the dynamic nature of CML.
In summary, the molecular pathogenesis of CML is intricately linked to the role of hematopoietic stem cells and genetic mutations, including the BCR-ABL fusion gene, secondary mutations, and the overall mutational landscape. These insights pave the way for enhanced diagnostic and therapeutic strategies, which can significantly affect patient outcomes.
Clinical Manifestations of
Understanding the clinical manifestations of chronic myeloid leukemia (CML) is crucial. These manifestations provide insight into the disease's progression and severity. Recognizing the symptoms is vital for timely diagnosis and treatment, which can significantly affect patient prognosis. CML evolves gradually, and its manifestations change depending on the stage of the disease. This makes it important to be aware of the unique signs associated with each stage.
Symptoms and Signs
CML often presents with nonspecific symptoms that can easily be overlooked. Common symptoms include fatigue, weakness, weight loss, and night sweats. Patients may also experience splenomegaly, leading to abdominal discomfort or fullness. These symptoms can arise from the accumulation of abnormal white blood cells. Additionally, some patients may show signs of hyperleukocytosis, which can present as respiratory distress due to increased white blood cell count.
In some cases, patients may discover their illness incidentally through routine blood tests, which reveal elevated white blood cell counts. This highlights the importance of regular health check-ups, especially for individuals at higher risk of developing CML.
Stages of
Chronic Phase
The chronic phase is the initial stage of CML. It is characterized by a relatively stable condition where patients may experience few or no symptoms. The disease often progresses slowly during this phase, making it less noticeable. This aspect makes the chronic phase a vital point of focus in understanding CML.
A key characteristic of this phase is the presence of the BCR-ABL fusion gene, which plays a central role in the pathogenesis of CML. This phase is generally favorable for treatment as most patients respond well to Tyrosine Kinase Inhibitors like Imatinib. Moreover, the chronic phase allows physicians to monitor the disease without aggressive intervention, thus reducing treatment-related complications.
Accelerated Phase
The accelerated phase marks a transition in CML. This stage involves more aggressive disease features, including an increased number of immature white blood cells. Patients may experience more pronounced symptoms, such as fever and worsening fatigue. The significance of this phase lies in its reflection of disease progression.
A key characteristic of the accelerated phase is the increase in blast cells, which outnumbers normal myeloid cells. This phase represents a crucial turning point that requires closer monitoring. If not addressed, it can lead to rapid progression to the blastic phase. This time, treatment options may become limited, and achieving remission can become increasingly difficult.
Blastic Phase
The blastic phase is the final stage of CML. It is marked by acute leukemia features. Patients may present with severe symptoms and an overwhelming number of blast cells in the blood and bone marrow. This phase presents significant challenges in management and treatment.
A key characteristic of the blastic phase is the aggressive nature of the disease, leading to rapid deterioration in patient health. The presence of myeloid or lymphoid blasts complicates treatment options, often necessitating more aggressive therapies like chemotherapy or stem cell transplantation. Informing patients about this phase is essential, as it represents critical clinical deterioration and a change in treatment strategy.
The clinical manifestations of CML evolve significantly across its stages, impacting both the diagnosis and therapeutic approaches.
Diagnosis of
The diagnosis of chronic myeloid leukemia (CML) is an essential step in the management of this malignancy. Early detection can significantly improve patient outcomes and provide a foundation for effective treatment strategies. There are several critical elements in the diagnostic process that include histological examination, cytogenetic analysis, and advanced molecular testing techniques. Understanding how these diagnostic procedures contribute to accurate identification of CML can help inform clinicians on the best therapeutic approaches.
Histological Examination
Histological examination involves the microscopic analysis of blood and bone marrow samples. The primary objective is to identify abnormal cell morphology characteristic of CML. A peripheral blood smear often reveals high white blood cell counts with immature myeloid cells. Furthermore, bone marrow biopsy can show hypercellularity and increased granulocyte precursors.
This examination not only confirms the presence of CML but also helps differentiate it from other hematologic disorders. The identification of the blast phase may signal disease progression, affecting treatment decisions. A comprehensive histological evaluation can thus provide vital insights into the disease's stage and severity.
Cytogenetic Analysis
Cytogenetic analysis focuses on identifying chromosomal abnormalities in cancer cells. In the case of CML, the hallmark is the presence of the Philadelphia chromosome, resulting from the translocation between chromosomes 9 and 22, leading to the formation of the BCR-ABL fusion gene. This analysis is integral for confirming a CML diagnosis and acts as a guide for therapeutic strategies.
By utilizing techniques such as fluorescence in situ hybridization (FISH) and karyotyping, clinicians can assess the extent of chromosomal changes. This evaluation helps determine the prognosis, as patients with a higher percentage of Philadelphia-positive cells may have a more severe disease course. Moreover, cytogenetic findings are crucial for monitoring response to treatment over time, helping practitioners adjust therapy when necessary.
Molecular Testing Techniques
Molecular testing techniques play a crucial role in the diagnosis and management of CML. They offer insights into the genetic profile of the disease. Two popular molecular testing methods are Polymerase Chain Reaction and Next-Generation Sequencing. Each method contributes uniquely to understanding the genetic landscape of CML.
Polymerase Chain Reaction (PCR)
Polymerase Chain Reaction (PCR) is a widely used molecular technique. It allows for the amplification of specific DNA sequences, enabling the detection of the BCR-ABL fusion gene with high sensitivity. This method is beneficial due to its speed and precision in identifying any residual disease after treatment.
The efficiency of PCR lies in its specificity. It can differentiate between various forms of the BCR-ABL fusion transcript, providing useful prognostic information. However, PCR may not reveal all types of mutations that might confer resistance to treatment. Thus, while it remains a popular choice, it is important to couple PCR results with other testing methods for a more comprehensive approach.
Next-Generation Sequencing (NGS)
Next-Generation Sequencing (NGS) is revolutionizing the landscape of molecular diagnostics. NGS enables researchers to analyze multiple genes and mutations simultaneously, providing a broader view of the genetic alterations in CML. This method identifies resistance mutations and offers a deeper understanding of the mutational landscape.
A key characteristic of NGS is its high throughput capacity and ability to generate vast amounts of data. This feature is particularly advantageous for evaluating complex cases of CML, where traditional methods may fall short. Despite its benefits, NGS can be expensive and may require substantial bioinformatics support to interpret the results accurately. Thus, while NGS offers comprehensive insights, practical considerations must be taken into account during implementation.
Treatment Options for
Understanding the treatment options available for chronic myeloid leukemia (CML) is essential for managing the disease effectively. As CML is primarily driven by the BCR-ABL fusion gene, targeted therapies have emerged as frontline options. The primary objective of treatment is to control the disease and prolong survival, while also minimizing side effects. The choice of treatment often depends on the phase of the disease, patient's health status, and response to prior therapies.
Effective management includes consideration of tyrosine kinase inhibitors (TKIs), stem cell transplantation, and emerging therapies aimed at addressing resistance mutations. Each treatment option has implications for patient lifestyle, symptom management, and overall outcomes.
Tyrosine Kinase Inhibitors
Tyrosine kinase inhibitors have transformed the treatment landscape for CML. These medications specifically target the BCR-ABL fusion protein that drives the cancer. Their introduction has significantly improved survival rates and the quality of life for patients.
Imatinib
Imatinib is the first-generation TKI that gained attention for its potent efficacy against BCR-ABL positive CML. It works by inhibiting the activity of the fusion protein, leading to decreased proliferation of malignant cells.
A key characteristic of Imatinib is its oral administration, which allows for convenient outpatient management. This ease of use makes it a popular choice in clinical settings.
However, Imatinib has unique features such as the potential for resistance due to mutations in the BCR-ABL gene. The advantages include a significant reduction in disease progression and transformation rates. Disadvantages may involve side effects like edema and gastrointestinal upset.
Dasatinib
Dasatinib is considered a second-generation TKI that is effective for patients who are resistant to Imatinib. Its mechanism of action is similar, but it has a broader inhibitory profile, impacting other kinases as well.
One notable aspect of Dasatinib is its marketed flexibility in dosing, which can vary from patient to patient. This adaptability is beneficial as it allows fine-tuning of therapy based on individual response.
However, Dasatinib can present some side effects, including pleural effusions and pulmonary hypertension. These considerations make careful monitoring necessary when using this drug.
Nilotinib
Nilotinib is another second-generation TKI that has emerged as an important option for patients with CML. It demonstrates a higher potency against BCR-ABL compared to Imatinib.
Its key characteristic includes its ability to achieve faster reductions in disease burden, which can lead to improved outcomes in treatment-naive patients.
The unique feature of Nilotinib is its lower incidence of some side effects seen with first-generation TKIs. However, one must be cautious of potential cardiovascular risks, which are a noted disadvantage in some patients.
Stem Cell Transplantation
Stem cell transplantation remains a viable treatment option, especially in advanced stages of CML or when TKIs are ineffective. This procedure can provide a potential cure by replacing diseased marrow with healthy cells from a compatible donor.
Patient selection for this treatment is critical, often taking into account age and overall health. While transplantation can lead to long-term remission, it also carries risks like graft-versus-host disease and infections.
Emerging Therapies
Emerging therapies are developing to target the challenges presented by drug resistance in CML. As resistance mechanisms evolve, researchers aim to create more effective therapeutic strategies.
Targeting Resistance Mutations
Targeting resistance mutations involves identifying specific genetic changes in the BCR-ABL gene that reduce the effectiveness of existing therapies. Novel agents are being designed to selectively inhibit these mutated forms.
This strategy is particularly beneficial as it seeks to personalize treatment approaches, catering to the unique profile of resistance in each patient.
However, the challenges remain. Understanding these mutations is complex, and successful targeting requires extensive research and clinical validation.
Novel Agents in Development
There are several novel agents in development aimed at improving treatment outcomes in CML. These include various compounds that show promise in preclinical studies. Some focus on the inhibition of alternative signaling pathways that become activated in resistant cases.
A key characteristic of these agents is their ability to potentially provide new hope for patients who have exhausted standard treatment options. New agents may offer distinct advantages; however, their efficacy will need validation through clinical trials.
The landscape of CML treatment is evolving, with novel approaches holding the promise of improving the management and outcomes for patients, especially those confronting treatment resistance.
In summary, the exploration of treatment options for chronic myeloid leukemia is marked by advancements in therapeutic strategies. Ongoing research continues to shed light on new possibilities to enhance patient care.
Monitoring Response to Treatment
Monitoring response to treatment in chronic myeloid leukemia (CML) is a critical component of managing the disease effectively. The process allows for the assessment of how well the treatment is working and helps clinicians decide on the future course of action. Regular monitoring can guide modifications in therapy, optimizing efficacy while minimizing adverse effects. Understanding both molecular and cytogenetic responses is essential in evaluating treatment outcomes.
Molecular Response Assessment
Molecular response assessment focuses on detecting the presence of the BCR-ABL fusion gene, which is responsible for the abnormal growth of myeloid cells in CML. The most common technique used is real-time quantitative polymerase chain reaction (qPCR). This test quantifies the transcript levels of the BCR-ABL gene. A complete molecular response indicates the absence of detectable BCR-ABL levels.
Achieving an early complete molecular response is an important prognostic factor. Patients showing this response tend to have better long-term outcomes. Observing the trends in molecular response can indicate whether a patient may need a change in therapy to address potential resistance mutations.
Key points about molecular response assessment include:
- It offers a quantitative measure of treatment effectiveness.
- Helps in identifying patients who may harbor resistance mutations.
- Essential data for considering treatment discontinuation in certain patients.
Cytogenetic Response Monitoring
Cytogenetic response monitoring involves analyzing chromosomal abnormalities, primarily through techniques like fluorescence in situ hybridization (FISH). The focus here remains on detecting the Philadelphia chromosome that exhibits the BCR-ABL fusion. Evaluating cytogenetic response helps categorize patients based on their level of response: complete cytogenetic response, partial cytogenetic response, or no response.
A complete cytogenetic response suggests that no Philadelphia chromosomes are detected in the cells. This result is linked with favorable outcomes and is closely monitored over time. It provides a broader understanding of the genetic stability of hematopoietic cells in CML patients.
In summary, cytogenetic response monitoring can:
- Clarify the extent of chromosomal changes in response to treatment.
- Serve as a guideline for therapy adjustments and future prognosis.
- Complement molecular testing to create a more comprehensive treatment assessment framework.
Understanding both molecular and cytogenetic assessments is vital in tailoring treatment plans for optimal patient outcomes.
Challenges in Management
Managing chronic myeloid leukemia (CML) poses various complexities that clinicians must navigate. These challenges significantly impact patient outcomes and highlight the need for ongoing research and innovative strategies. Understanding these hurdles can guide healthcare professionals in optimizing treatment plans for individuals diagnosed with this condition.
The most pressing of these challenges is drug resistance. It arises when cancer cells evolve, rendering treatments less effective or even ineffective. This scenario demands a dynamic response from healthcare providers, who must continuously evaluate the effectiveness of ongoing therapies. Moreover, adverse effects of treatments can complicate management. Health professionals must balance the intensity of therapeutic interventions with the quality of life experienced by patients.
Drug Resistance
Drug resistance in CML can be both inherent and acquired, often resulting from genetic mutations within the leukemia cells. The BCR-ABL fusion gene is a primary target of tyrosine kinase inhibitors, such as Imatinib. However, various mutations in this gene can cause resistance, complicating treatment regimens.
Key Factors Contributing to Drug Resistance:
- The presence of kinase domain mutations: These mutations can change the structure of the BCR-ABL protein, preventing inhibitors from binding effectively.
- Drug transport mechanisms: Cancer cells can develop methods to pump drugs out, reducing the effective concentration of the medication.
- Clonal evolution: A diverse population of leukemic cells can emerge, with some cells harboring resistance mutations.
Addressing drug resistance often requires a multi-faceted approach. Therapeutic strategies may include:
- Switching to second-generation tyrosine kinase inhibitors like Dasatinib and Nilotinib.
- Exploring new agents that target different pathways or mechanisms.
- Consideration of combination therapies to limit the likelihood of resistance developing.
Adverse Effects of Treatment
While treatment options for CML have expanded significantly over the past decades, they are often associated with a range of adverse effects. These effects can vary based on the specific drug, individual patient factors, and treatment duration. Understanding these adverse effects is crucial for healthcare practitioners.
Common Adverse Effects Include:
- Gastrointestinal Issues: Nausea, diarrhea, and abdominal pain can disrupt daily life for patients.
- Bone Marrow Suppression: This often results in anemia, increasing the risk of infections and bleeding.
- Cardiovascular Complications: Certain treatments may affect cardiovascular health, warranting close monitoring.
Managing these adverse effects requires proactive strategies. Common approaches are:
- Dose adjustments or changing medications if severe side effects occur.
- Supportive measures such as antiemetics for nausea and growth factors for blood cell support.
- Regular monitoring for cardiovascular health in susceptible patients.
"By understanding the challenges in chronic myeloid leukemia management, healthcare professionals can enhance care strategies and ultimately improve patient quality of life."
Collaboration among researchers, clinicians, and patients remains integral in developing newer, more effective approaches to tackle these hurdles.
Future Directions in Research
The landscape of chronic myeloid leukemia (CML) research is evolving rapidly. Understanding the mutations involved and their implications is crucial for advancing treatment outcomes. This section will discuss innovative approaches and personalized medicine, which are vital to the future of CML management.
Innovative Genetic Approaches
Recent years have seen a surge in interest surrounding innovative genetic techniques to understand CML better. One key area includes the comprehensive analysis of whole-genome sequencing and its role in identifying novel mutations. These methods have proven integral in revealing genetic abnormalities beyond the well-known BCR-ABL fusion gene.
The benefits of these approaches extend into several areas:
- Identification of New Mutations: Whole-genome and whole-exome sequencing can uncover previously unknown mutations that contribute to drug resistance.
- Understanding Disease Progression: These techniques help map the mutational landscape, facilitating insights into how genetic changes influence the transition between CML phases.
Furthermore, single-cell sequencing is emerging as a useful tool. It enables researchers to study tumor heterogeneity at an unprecedented level. By assessing individual cells, researchers can determine how mutations vary within a population, shedding light on their implications for treatment strategies.
The increased understanding garnered through these genetic approaches has significant implications for future studies and therapies. They may lead to identifying new therapeutic targets and enhancing the effectiveness of current treatments, ultimately improving patient outcomes.
Personalized Medicine in
Personalized medicine represents a paradigm shift in how chronic myeloid leukemia is managed. Tailoring treatments based on individual genetic profiles can maximize efficacy while minimizing adverse effects.
Several aspects underscore the importance of personalized medicine in CML:
- Targeted Therapies: The development of targeted therapies, such as second-generation tyrosine kinase inhibitors, has revolutionized treatment options. However, effectiveness can vary based on specific mutations present in the patient.
- Patient-Specific Model Systems: Researchers are increasingly employing patient-derived xenografts to develop model systems that accurately mimic an individual’s disease. This can provide insights into which therapies will be most effective based on the specific genetics of the patient's leukemia.
"Personalized medicine allows for a tailored approach to treatment, ensuring that each patient receives the most appropriate therapeutic intervention."
Moreover, the implementation of pharmacogenomics—analyzing how genes affect a person's response to drugs—could lead to optimizing dosages and minimizing toxicities associated with various therapies. This technique may enhance the quality of life for CML patients significantly.
