Blood cancer, a group of diseases affecting blood cell production and function, often raises questions about its hereditary nature. While most blood cancers are not directly passed down through families, a notable portion has a hereditary component. Understanding this genetic link can help individuals and families assess their personal risk.
How Cancer Can Be Hereditary
Cancer development often involves changes, or mutations, in a cell’s DNA. These mutations can be broadly categorized as either acquired (somatic) or inherited (germline). Somatic mutations occur during a person’s lifetime in specific cells and are not passed on to offspring. The vast majority of cancers, including blood cancers, arise from these acquired genetic changes, often due to random errors in cell division or environmental exposures.
Inherited, or germline, mutations are present in every cell of the body from birth, having been passed down from a parent through an egg or sperm cell. While inheriting such a mutation increases an individual’s risk of developing certain cancers, it does not guarantee cancer will occur. These inherited mutations can lead to “cancer predisposition syndromes,” which significantly elevate a person’s likelihood of developing specific cancers. For a healthy cell to become cancerous, multiple DNA changes typically accumulate over many years. Individuals born with an inherited mutation start with one such change, meaning fewer additional mutations are needed for cancer to develop, often leading to an earlier age of onset.
Blood Cancers with a Hereditary Link
While most blood cancers are sporadic, approximately 4.1% of blood cancer diagnoses have a hereditary link. Certain genes are known to cause inherited forms of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), including mutations in RUNX1, CEBPA, and GATA2. Familial platelet disorder with propensity for myeloid malignancies, linked to RUNX1 mutations, can lead to MDS, AML, or T-cell acute lymphoblastic leukemia (T-ALL).
Chronic Lymphocytic Leukemia (CLL) is another blood cancer with a notable hereditary component, being one of the most heritable cancers. A family history of CLL is a well-defined risk factor, with approximately 15-20% of CLL patients having a family member with the condition. Individuals with a first-degree relative diagnosed with CLL can have a six-fold higher risk of developing the condition compared to the general population. The risk for CLL can be even higher if the relative was diagnosed at a younger age or if multiple first-degree relatives are affected. Certain subtypes of Hodgkin lymphoma, lymphoplasmacytic lymphoma, and mantle cell lymphoma also show strong familial links.
Understanding Your Personal Risk
Several factors can suggest a potential hereditary risk for blood cancer. These include having multiple family members diagnosed with blood cancer, particularly on the same side of the family, or if cancers occurred at an unusually young age. The presence of rare types of cancer within a family, or an individual developing multiple different cancers, can also be indicators. These patterns hint at an underlying inherited genetic change rather than shared environmental factors.
If these indicators are present in your family history, discussing them with your doctor is an important first step. Your doctor may recommend genetic counseling, which involves a specialized healthcare professional assessing your personal and family medical history in detail. Genetic counselors can provide personalized risk assessments and discuss the potential for genetic testing. Genetic testing involves analyzing a blood or saliva sample to identify specific inherited gene changes that may increase cancer risk. It is important to remember that not everyone with a family history needs genetic testing, and genetic counselors can help determine if testing is appropriate and interpret the results.