The ALK gene helps cells send growth signals, especially during early development of the nervous system. If the ALK gene becomes rearranged or otherwise overactive, cells can keep growing when they should not, which can contribute to cancers such as some lung cancers, lymphomas, and neuroblastoma. Many clinicians pay attention to this gene when they assess a tumor, because finding an ALK change can help explain why it is growing and may guide treatment choices.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or to guide processes throughout the body. Some provide the directions for building proteins, which are the parts of cells that do the work. Others mainly help regulate when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can influence how you respond to food, stress, or medications. For a more detailed explanation of this topic, you can read more in the LearnHub.
Overview
ALKGene function
What if the gene works
The ALK gene helps guide growth and communication in parts of the nervous system, especially before birth and in early life. It gives cells instructions for a signaling protein that supports normal development.
Risk
What if the gene does not work
Changes in the ALK gene can drive cancers, especially some lung cancers, anaplastic large cell lymphoma, and neuroblastoma. Milder and more severe variants can influence which cancer develops, how early it appears, and how strongly cells are pushed to grow.
Treatment
What does that mean for your treatment
For the ALK gene, treatment relevance is mainly linked to activating fusions or variants rather than loss of function. These changes can make ALK targeted medicines such as alectinib, brigatinib, lorlatinib, crizotinib, or ceritinib appropriate, depending on the cancer type and prior treatment. Loss of function in the ALK gene does not currently guide a standard treatment choice.
Conditions associated with ALK
Gene function
What if the gene works
One of the clearest parts of ALK gene function is its role in nerve cell development. The ALK gene helps cells receive growth signals and pass them inward, especially during early development. This supports how immature nerve cells grow, mature, and connect in a coordinated way.
The ALK gene makes a protein on the cell surface that picks up specific chemical messages. It then passes that signal inward, helping cells respond to timed cues about growth and maturation.
The ALK gene is especially important for developing nerve cells. It helps these cells grow, mature, and build connections as the nervous system takes shape.
Inside cells, ALK signaling turns on pathways that guide normal development. These pathways help coordinate when cells grow, specialize, and stay in step with nearby cells.
What is a variant?
A genetic variant is a small change in the DNA sequence of a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, and how the body responds to environmental influences. Many variants do not have any noticeable effect and are simply part of natural genetic variation. In some cases, though, a variant can change how a gene functions more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Many ALK gene variants change the shape or control of the ALK protein, a cell signaling switch, so it stays active when it should be quiet. In many cancers, this happens through activating variants, extra copies of the ALK gene, or fusion changes that join ALK to another gene; this is how ALK gene variants affect cell signaling and drive ongoing growth signals. Different variants can turn the signal up by different amounts, and some also change how well ALK targeted medicines can attach.
How variants are linked to conditions
Conditions linked to variants in the ALK gene include a hereditary tendency to neuroblastoma and several cancers with acquired tumor changes. Inherited pathogenic variants in the ALK gene can cause a higher chance of neuroblastoma in families, usually affecting infants and young children, though not every carrier develops cancer. Acquired ALK changes are associated with some tumors, especially ALK-positive non-small cell lung cancer, anaplastic large cell lymphoma, and inflammatory myofibroblastic tumor.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are common throughout the general population. Most do not have a direct effect on health and simply reflect natural human variation. For many genes, carrying a variant associated with a condition indicates a possible link rather than a definite diagnosis, especially when several genes and environmental factors also contribute. In some situations, though, a single well-characterized variant in a particular gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There is not yet broadly confirmed evidence on specific day-to-day factors that clearly increase or reduce risk related to the ALK gene. In families with an inherited ALK change, risk is mainly shaped by the gene change itself rather than lifestyle. Anyone concerned about personal or family risk should speak with a doctor or genetic counselor.
Inheritance of ALK variants
For families asking how ALK gene variants are inherited, the well-established inherited pattern is autosomal dominant for ALK-related neuroblastoma susceptibility. This means a parent carrying a pathogenic variant in the ALK gene can pass it to a child with a 50% chance in each pregnancy, whether the child is a son or a daughter. Some people with an ALK gene variant never develop cancer, so inheritance of the variant is not the same as a diagnosis. Some cases also result from a new, de novo variant and are not inherited from either parent.
What does my ALK result mean for my family?
For inherited ALK changes linked to familial neuroblastoma, close relatives such as parents, brothers, sisters, and children may also carry the same change, so the result can matter beyond one person. This pattern is usually passed down in families in a dominant way, but not everyone who carries an ALK change will develop cancer. Some ALK changes can also start new in one child, so a parent does not always carry the same result.
Genetic information
Genetic testing
How you find out about variants
To find out about ALK gene variants, genetic testing reads DNA from blood or saliva for inherited changes, or from a tumor sample for acquired changes linked to cancer. Labs use methods such as sequencing or fusion testing to look for extra, missing, or rearranged DNA pieces in the ALK gene.
When should I consider getting a genetic test?
Testing for changes in the ALK gene may be worth discussing if a child has a nerve cell cancer called neuroblastoma, especially if more than one family member has had it or it started very early. In some other cancers, testing the tumor for ALK changes can also help guide treatment.
A genetic result is only one part of your health story
Genetic findings can be very informative, but how much they reveal varies depending on the condition and the type of variant involved. Over time, the way the body works is also shaped by many other factors, including lifestyle, environment, age, and medical history. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is best understood alongside other parts of care. In other situations, a genetic result can provide a clear answer. In areas like medication response, these results can also help make sense of individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic differences can affect how your body responds to medicines. This helps explain why the same treatment works well for one person but causes more side effects or less benefit for another. Variants in different genes can change how a drug is handled in the body or how strongly the body responds to it. These differences are common and can influence how well a treatment works or how sensitive someone is to it.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape the way a person responds to medicines. It studies gene drug patterns to help explain why the same treatment may work differently from one person to another. With many medications, genes can influence how powerfully a drug works or how the body handles it. This information can support treatment decisions that are better informed and more individualized. More detail on this topic is available in the LearnHub.
Drugs influenced by the ALK gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in routine medication response, so general questions about medicines or side effects are best discussed with your doctor. ALK is mainly used in cancer care, where changes in tumor cells can help guide some targeted treatments. If you are being treated for an ALK-positive cancer, speak with your cancer team before starting or changing treatment.
History
ALK entered cancer genetics in the 1990s, when researchers found that a chromosome swap involving the ALK gene was linked to anaplastic large cell lymphoma. This discovery helped show that some cancers are driven by specific gene changes rather than only by where they start in the body. From these first observations, research expanded steadily. In 2007, scientists identified ALK rearrangements in a small group of people with non small cell lung cancer, which quickly changed testing and treatment approaches. That finding led to the development of targeted medicines aimed at ALK related cancers. Over time, ALK became one of the clearest examples of how gene discoveries can reshape cancer care.