CD30 is a protein found on the surface of certain cells, particularly immune cells like lymphocytes. It functions as a receptor, meaning it receives signals from outside the cell and transmits them inward, influencing cellular activities such as proliferation and survival. As a member of the tumor necrosis factor (TNF) receptor family, CD30 plays a role in regulating immune responses, including the activation of immune cells. Its presence on the cell surface makes it a detectable marker.
CD30’s Role in Certain Cancers
CD30’s presence is particularly notable in certain types of cancer, where it is often found in abnormally high amounts on the surface of malignant cells. This overexpression is a distinguishing feature of conditions such as Hodgkin Lymphoma (HL) and Anaplastic Large Cell Lymphoma (ALCL). Approximately 90% of Hodgkin Lymphoma cases show CD30 expression. This consistent presence on cancer cells makes CD30 a significant marker for these diseases.
In ALCL, CD30 is strongly expressed, and this expression can be linked to a fusion protein called nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), which is present in 50% to 70% of ALCL cases due to a specific chromosomal translocation. Reducing NPM-ALK expression can lead to decreased CD30 levels and reduced cell proliferation in ALCL cells. While the exact function of CD30 overexpression in ALCL development is still being explored, its association with these aggressive lymphomas is significant for understanding their progression.
Diagnosing Diseases with CD30
The presence of CD30 on the surface of cancer cells allows it to be used as a diagnostic tool. Techniques like immunohistochemistry (IHC) and flow cytometry (FCM) are used to detect CD30 expression in patient samples, such as tissue biopsies or blood. IHC involves using antibodies that bind specifically to CD30, which are then visualized to show the protein’s location within tissue sections. This method provides information about both the tissue architecture and the protein’s expression pattern.
Flow cytometry offers a quantitative approach, enabling rapid and sensitive detection of CD30 on individual cells in a suspension. It is useful for detecting markers that are expressed at low levels. Combining both IHC and flow cytometry provides a comprehensive assessment of CD30 expression, aiding in the accurate classification of hematological malignancies and helping to differentiate certain lymphomas, such as ALCL, from other conditions. For example, in classic Hodgkin lymphoma, tumor cells show strong positivity for CD30.
Targeting CD30 for Treatment
CD30’s consistent presence on lymphoma cells has made it an attractive target for cancer therapies, leading to targeted treatments. Brentuximab Vedotin is a prominent example, an antibody-drug conjugate (ADC) designed to deliver a potent chemotherapy agent directly to CD30-expressing cells. This ADC consists of three main components: an antibody that specifically binds to CD30, a linker connecting the antibody to the chemotherapy drug, and the cytotoxic agent, monomethyl auristatin E (MMAE).
When Brentuximab Vedotin binds to CD30 on a cancer cell, the complex is internalized. Inside the cell, the linker is cleaved by enzymes, releasing the MMAE. This released MMAE disrupts the cell’s internal structure, interfering with microtubules essential for cell division. This disruption leads to cell cycle arrest and programmed cell death. Brentuximab Vedotin is effective and approved for patients with relapsed or refractory Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma.