DNA transforming into flowers, symbolizing hope in genetic research

Decoding MLL/CBL Gene Fusions: What You Need to Know About Leukemia's Hidden Culprit

Elliot Brynn in Health & Wellness August 2025 • 4 min read.

"A Simple Guide to Understanding del(11)(q23q23) and Its Impact on Acute Myeloid Leukemia"

For many, the world of genetics feels like navigating a complex maze filled with unfamiliar terms and intricate processes. However, understanding the basics can be empowering, especially when facing health challenges like leukemia. One area of significant interest is the MLL/CBL gene fusion, particularly the deletion del(11)(q23q23), which plays a role in specific types of acute myeloid leukemia (AML).

This article aims to demystify the MLL/CBL gene fusion, breaking down the scientific jargon into easy-to-understand language. We will explore what this genetic anomaly is, how it's identified, its implications for health, and current approaches to treatment. Whether you're a patient, a family member, or simply someone curious about genetics, this guide is designed to provide clarity and support.

The information presented here is based on research published in the 'Atlas of Genetics and Cytogenetics in Oncology and Haematology,' a respected resource in the field. By synthesizing this information, we hope to offer a practical and accessible overview of a complex topic.

What is del(11)(q23q23) MLL/CBL?

DNA transforming into flowers, symbolizing hope in genetic research

In simple terms, del(11)(q23q23) MLL/CBL refers to a specific type of genetic alteration where a portion of chromosome 11 is deleted. This deletion involves two genes: MLL (Mixed Lineage Leukemia) and CBL (Casitas B-lineage Lymphoma). These genes, normally separate, become fused together due to the deletion, leading to the creation of a hybrid gene.

To understand this better, let's break down the components:

Chromosome 11: Think of chromosomes as the 'books' containing our genetic information. Humans have 23 pairs of chromosomes, and chromosome 11 is one of them.
q23q23: This is the specific location on chromosome 11 where the deletion occurs. 'q' refers to the long arm of the chromosome, and '23' indicates a particular region on that arm.
MLL Gene: The MLL gene provides instructions for making a protein crucial for the normal development of blood cells. When this gene is altered, it can lead to leukemia.
CBL Gene: The CBL gene is involved in regulating cell growth and signaling pathways. It acts as a tumor suppressor, preventing cells from growing uncontrollably.
Gene Fusion: In del(11)(q23q23) MLL/CBL, the deletion causes parts of the MLL gene to fuse with parts of the CBL gene. This creates a new, abnormal protein that can disrupt normal cell function and contribute to the development of leukemia.

The fusion protein created by del(11)(q23q23) joins parts of MLL and CBL, disrupting normal cellular processes. MLL normally helps regulate gene expression, while CBL regulates cell growth. The fusion interferes with these regulatory functions, potentially causing uncontrolled cell proliferation.

What Does This Mean for Treatment and Prognosis?

The identification of del(11)(q23q23) MLL/CBL is crucial for diagnosis and treatment planning. According to the original research, the patient described achieved complete remission with chemotherapy and remained in remission for 25 months. While this is just one case, it highlights the importance of understanding the specific genetic profile of leukemia to tailor treatment effectively. Ongoing research continues to explore targeted therapies that can specifically address the MLL/CBL fusion protein, potentially leading to more effective and less toxic treatments in the future. If you or a loved one is affected by leukemia, discuss genetic testing and its implications with your healthcare provider to ensure the most informed and personalized treatment approach.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

Everything You Need To Know

What exactly happens at the genetic level with del(11)(q23q23) MLL/CBL?

The alteration del(11)(q23q23) MLL/CBL involves a deletion on chromosome 11, specifically at the q23q23 location. This deletion results in the fusion of the MLL gene and the CBL gene, creating an abnormal hybrid gene. This fusion disrupts normal cellular functions because the MLL gene, which is crucial for blood cell development, and the CBL gene, a tumor suppressor, are now combined, leading to potential issues like uncontrolled cell growth.

What is the typical function of the MLL gene, and how does del(11)(q23q23) MLL/CBL affect it?

The MLL gene is located on chromosome 11 and provides instructions for creating a protein essential for the development of blood cells. When the MLL gene is altered, as in the case of del(11)(q23q23) MLL/CBL, it can lead to the development of leukemia by disrupting normal gene expression. The MLL gene's normal function is to regulate gene expression, which is vital for proper cell differentiation and proliferation. In the context of the fusion, this regulation is compromised.

What role does the CBL gene normally play in the body, and how does its fusion with MLL in del(11)(q23q23) impact its function?

The CBL gene is also located on chromosome 11 and plays a critical role in regulating cell growth and signaling pathways and acts as a tumor suppressor. In del(11)(q23q23) MLL/CBL, the CBL gene fuses with the MLL gene due to a deletion. This fusion can disrupt its normal function as a tumor suppressor, contributing to the uncontrolled growth of cells and potentially leading to leukemia. Normally, the CBL gene prevents cells from growing uncontrollably, maintaining balance in cell proliferation.

How does the identification of del(11)(q23q23) MLL/CBL influence treatment strategies and outcomes for leukemia?

Identifying del(11)(q23q23) MLL/CBL is very important for tailoring treatment strategies in leukemia. In the case described, the patient achieved complete remission with chemotherapy and remained in remission for 25 months, emphasizing the role of understanding the genetic profile of the leukemia for effective treatment. Future treatments will likely involve targeted therapies aimed specifically at the MLL/CBL fusion protein, potentially reducing toxicity and improving outcomes. Genetic testing for MLL/CBL fusions can also help determine prognosis and guide decisions about the intensity and type of therapy.

How does the MLL/CBL gene fusion resulting from del(11)(q23q23) disrupt normal cellular processes and contribute to the development of leukemia?

The MLL/CBL gene fusion resulting from del(11)(q23q23) disrupts normal cellular processes by creating an abnormal fusion protein. This fusion protein, made of parts of MLL and CBL, interferes with gene expression and cell growth regulation, potentially leading to uncontrolled cell proliferation and contributing to leukemia. Understanding the specific molecular mechanisms of this disruption is crucial for developing targeted therapies.