We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Health

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Are Tumor-Associated Macrophages?

By Geisha A. Legazpi
Updated: May 17, 2024
Views: 8,281
Share

Tumor-associated macrophages (TAMs) are inflammatory cells found in malignant tumors that play important roles in tumor growth, progression, and metastases. Macrophages are normally part of the body’s immune response against any aberration, including foreign bodies and tumors. Tumor-associated macrophages may produce pro-tumor substances, such as those that enable both the formation of new blood vessels, or angiogenesis, and tissue remodeling, leading to tumor progression and metastases. They may also produce anti-tumor substances that lead to cell killing, or cytotoxicity, and programmed cell death, or apoptosis.

Macrophages are derived from cells called monocytes, which are produced from pluripotent stem cells in bone marrow. When there is an event that induces inflammation, such as injury or infection, monocytes are recruited to the involved site and are activated to become macrophages. Macrophages normally function in antigen presentation in order to activate other immune cells and hasten the removal of debris, which facilitates tissue remodeling. They also enhance or amplify the immune response and are involved in eating up foreign bodies or infectious agents in a process called endocytosis.

When present in tumors, these macrophages become known as tumor-associated macrophages and may either inhibit or enhance tumor growth and metastases, leading to either progression or regression of the tumor. Tumor-associated macrophages can reduce the growth or induce the regression of the tumor through cytotoxic, cell-killing, or cell lysis mechanisms. Some substances released by tumor-associated macrophages that induce cell killing include hydrogen peroxidase, interleukin-1 (IL-1), tumor necrosis factor (TNF), nitrogen oxide, and reactive oxygen intermediates (ROIs).

TAMs may also release substances called cytokines and prostanoids that promote tumor cell growth and negate or suppress anti-tumor T cells and natural killer (NK) cells. These pro-tumor substances include interleukin-10 (IL-10) and prostaglandin E2 (PGE2). Through the release of various pro-tumor substances, the malignancy grows and may eventually metastasize.

Tumor-associated macrophages are being used for predicting outcomes such as progression, metastases, and survival because of their various activities, their presence, and their amount in certain cancers, such as human prostate cancer, breast cancer, esophageal cancer, and bladder cancer. Multiple breast cancer studies have shown that the pro-tumor capabilities of tumor-associated macrophages are more dominant in breast cancer because they lend a wound-healing ability to the tumor. Potential strategies for fighting cancer now include blocking the pro-tumor effects of tumor-associated macrophages. An example of this is the development of trabectedin, a drug from a marine turbinate that exhibits cytotoxicity against TAMs.

Share
WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Editors' Picks

Discussion Comments
Share
https://www.wisegeek.net/what-are-tumor-associated-macrophages.htm
Copy this link
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.