Cells communicate through proteins on their surfaces. These proteins act like antennae, receiving signals that guide cell behavior. One such protein, CD117, plays a significant role in various bodily functions. Specific antibodies that recognize and bind to CD117 have provided powerful tools for scientific research and medical diagnostics. This article explores CD117, how its antibodies are utilized, and their importance in detecting certain diseases.
What is CD117?
CD117, also identified as c-Kit or Stem Cell Factor Receptor (SCFR), is a receptor tyrosine kinase. These proteins are embedded in the cell membrane, extending both inside and outside the cell, and transmit signals from the cell’s exterior to its interior. When Stem Cell Factor (SCF) binds to CD117, it triggers internal signals that influence cell growth, division, and survival.
CD117 is present on the surface of several types of healthy cells. These include hematopoietic stem cells, precursors to all blood cells, and mast cells, involved in allergic reactions and immune responses. It is also found on melanocytes, responsible for skin pigment, and germ cells, involved in reproduction. In the digestive tract, CD117 is expressed on interstitial cells of Cajal, specialized cells that regulate gut movement.
How CD117 Antibodies Work
CD117 antibodies are specialized proteins designed to specifically recognize and attach to the CD117 protein found on cell surfaces. This binding ability is harnessed in laboratory and clinical settings to detect CD117-expressing cells.
The binding of CD117 antibodies can serve various purposes, such as identifying specific cell populations for research or diagnostic purposes, or in some cases, blocking CD117 protein activity. Two common laboratory techniques that use CD117 antibodies are immunohistochemistry (IHC) and flow cytometry. Immunohistochemistry involves applying antibodies to tissue samples, often stained with a visual marker, to highlight cells expressing CD117 under a microscope. Flow cytometry uses antibodies labeled with fluorescent dyes to identify and count CD117-positive cells in a liquid suspension, providing detailed information about cell populations.
CD117 Antibodies in Disease Detection
In certain disease states, CD117’s normal expression or function can become altered, making it a diagnostic indicator. Cells might produce excessive CD117, or the protein itself could be mutated, leading to uncontrolled cell growth. CD117 antibodies’ ability to specifically detect these changes aids pathologists and clinicians in accurately diagnosing and classifying various conditions.
CD117 antibodies are important in diagnosing Gastrointestinal Stromal Tumors (GISTs), the most common mesenchymal tumors of the gastrointestinal tract. Most GISTs (approximately 95%) express CD117 due to mutations in the KIT gene, which drives tumor growth. Detecting CD117 expression using antibodies helps confirm a GIST diagnosis and can guide treatment strategies, as many GISTs with KIT mutations respond to targeted therapies that inhibit CD117 activity.
CD117 antibodies also play a role in diagnosing certain subtypes of Acute Myeloid Leukemia (AML). While CD117 is expressed on early hematopoietic stem cells, its presence on leukemic blasts can help classify AML subtypes, particularly AML-M0, AML-M1, and AML-M2, where its expression is consistently observed. The antibody’s high specificity for myeloid lineage cells makes it a useful marker in distinguishing AML from other types of acute leukemias.
CD117 antibodies are used in diagnosing systemic mastocytosis, a rare disorder characterized by abnormal proliferation and accumulation of mast cells. Both normal and neoplastic mast cells express CD117, and its detection assists in identifying mast cell infiltrates in tissues such as bone marrow. This helps differentiate mastocytosis from other conditions and confirms the presence of these atypical mast cells.