Illustration of immune cells interacting within a thyroid gland.

Thyroid Cancer and Your Body: Unlocking the Secrets of Tumor Microenvironments

Nico Varela in Health & Wellness August 2025 • 4 min read.

"New research sheds light on how tumor-associated macrophages (TAMs) influence papillary thyroid carcinoma, offering hope for better treatments and understanding."

Papillary thyroid carcinoma (PTC) is the most frequently diagnosed endocrine malignancy, and its incidence has been steadily increasing over the past two decades. This rise is attributed to advances in diagnostic procedures, which allow for earlier detection. Due to the typically slow progression of PTC, managing these tumors has become a critical area of focus in endocrinological oncology.

The tumor microenvironment—the area surrounding the tumor that includes blood vessels, immune cells, signaling molecules, and the extracellular matrix—plays a crucial role in cancer development and progression. This complex environment influences how tumors grow, spread, and respond to treatment. Researchers are intensely studying the properties of the tumor microenvironment and the prognostic features of primary tumors to improve patient outcomes.

One key element within the tumor microenvironment is tumor-associated macrophages (TAMs). Macrophages are immune cells that can either promote or suppress tumor growth depending on their activation state. This article delves into a recent study that examined the relationships between specific types of TAMs and various clinical and pathological features of papillary thyroid carcinoma. By understanding these interactions, we can potentially develop more effective treatment strategies.

What Are Tumor-Associated Macrophages (TAMs) and Why Do They Matter?

Illustration of immune cells interacting within a thyroid gland.

Tumor-associated macrophages (TAMs) are a significant component of the tumor microenvironment. These immune cells originate from monocytes, which differentiate into two main subtypes: M1 and M2-like macrophages. M1 macrophages are classically activated and typically exhibit anti-tumor activity. M2-like macrophages, on the other hand, are alternatively activated and can promote tumorigenesis.

M2-like macrophages, particularly the M2d phenotype, express high levels of various factors that can influence tumor behavior. These factors include transforming growth factor ẞ (TGF-β), tumor necrosis factor a (TNF-α), interleukin 10 (IL-10), monocyte colony stimulating factor (M-CSF), vascular endothelial growth factors (VEGFs), matrix metalloproteinases (MMPs), and chemokines such as CCL17 and CCL22. Regardless of their origin, these TAMs are defined by their association with the tumor and their contribution to its progression.

Neovascularization: TAMs stimulate the growth of new blood vessels, providing the tumor with nutrients and oxygen.
Invasion and Metastasis: They promote the spread of cancer cells to other parts of the body.
Immune Suppression: TAMs can suppress the body’s natural anti-tumor immune responses, allowing the tumor to evade detection and destruction.

The study aimed to comprehensively assess how CD163-expressing M2-like TAMs interact with the primary tumor, the tumor microenvironment, tumor behavior, and markers of autoimmunity in patients with PTC. This included analyzing the density of M2-like TAMs in relation to tumor borders, intrathyroidal dissemination, lymphocytic tumor response, concomitant lymphocytic thyroiditis, stromal tumor response, markers of autoimmunity, and clinicopathological features (tumor size, extrathyroidal extension, lymph node metastasis).

Implications and Future Directions

This research underscores the multifaceted nature of TAMs in papillary thyroid carcinoma and highlights their potential as therapeutic targets. Further molecular studies are needed to fully elucidate the roles of these cells in tumor progression and dissemination. By gaining a deeper understanding of TAMs, we can pave the way for novel therapies that improve outcomes for patients with thyroid cancer.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.5114/pjp.2016.65865, Alternate LINK

Title: Histological Perspective On The Effects Of Tumor-Associated Macrophages In The Tumor Microenvironment Surrounding Papillary Thyroid Carcinoma

Subject: General Medicine

Journal: Polish Journal of Pathology

Publisher: Termedia Sp. z.o.o.

Authors: Nuray Y. Can, Semra Ayturk, Mehmet Celik, Yavuz A. Sezer, Filiz Ozyilmaz, Ebru Tastekin, Necdet Sut, Funda Ustun, Buket Yilmaz Bulbul, Fulya O. Puyan, Sibel Guldiken

Published: 2016-01-01

Everything You Need To Know

What is papillary thyroid carcinoma (PTC) and why is it a focus of research?

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, an endocrine malignancy. Its increasing incidence is linked to improved diagnostic methods that allow earlier detection. Because PTC usually grows slowly, managing it is a key focus in endocrinological oncology.

What is a tumor microenvironment and why is it important?

The tumor microenvironment is the area around a tumor, including blood vessels, immune cells, signaling molecules, and the extracellular matrix. It's important because it significantly affects how tumors grow, spread, and respond to treatment. Researchers study the tumor microenvironment to improve patient outcomes by understanding how tumors develop and progress.

What are tumor-associated macrophages (TAMs) and why is it important to understand them?

Tumor-associated macrophages (TAMs) are immune cells within the tumor microenvironment. They come from monocytes and differentiate into M1 and M2-like macrophages. M1 macrophages typically fight tumors, while M2-like macrophages can promote tumor growth. Understanding TAMs is crucial because their presence and type can significantly influence tumor behavior and progression.

What role do M2-like macrophages play in tumor development, and what factors do they produce?

M2-like macrophages, especially the M2d phenotype, produce substances such as transforming growth factor ẞ (TGF-β), tumor necrosis factor a (TNF-α), interleukin 10 (IL-10), monocyte colony stimulating factor (M-CSF), vascular endothelial growth factors (VEGFs), matrix metalloproteinases (MMPs), and chemokines like CCL17 and CCL22. These factors support neovascularization, invasion, metastasis, and immune suppression, aiding tumor progression. M2-like macrophages, through these factors, play a significant role in helping tumors thrive and spread.

What did the study investigate regarding tumor-associated macrophages (TAMs) and papillary thyroid carcinoma (PTC)?

The study examined how CD163-expressing M2-like tumor-associated macrophages (TAMs) interact with the primary papillary thyroid carcinoma (PTC) tumor. Specifically, it analyzed the density of M2-like TAMs in relation to tumor borders, intrathyroidal dissemination, lymphocytic tumor response, concomitant lymphocytic thyroiditis, stromal tumor response, markers of autoimmunity, and clinicopathological features like tumor size and lymph node metastasis. The goal was to understand how TAMs influence PTC progression and develop more effective treatment strategies.