Tumour Microenvironment in ICC
The tumor microenvironment (TME) in intrahepatic cholangiocarcinoma (iCCA) plays a pivotal role in tumor progression, immune evasion, and therapeutic resistance. iCCA is characterized by a highly complex and heterogeneous TME, comprising cancer cells, immune cells, stromal cells, extracellular matrix components, and signaling molecules. This intricate environment influences tumor growth, metastasis, and response to treatments.
Key players in the TME include tumor-associated macrophages, particularly CD163hi M2-like macrophages, which promote immune suppression and tumor progression by impairing CD8+ T cell-mediated antitumor responses. Cancer-associated fibroblasts (CAFs) contribute to the formation of a fibrotic barrier, preventing immune cell infiltration and creating an immunosuppressive milieu. Granulocytes and other myeloid cells further exacerbate immune suppression.
The TME in iCCA can be classified into distinct spatial subtypes, such as "immune hot," "immune suppressive," and "immune desert," which correlate with prognosis and treatment response. For example, immune hot TMEs, enriched in antitumor immune cells, are more responsive to immunotherapy, while immune desert TMEs, lacking immune cells, are associated with poor outcomes.
By influencing immune evasion mechanisms and modulating therapy resistance, the TME is a critical determinant of iCCA progression. Targeting the TME through combination therapies, such as immunotherapy and antifibrotic agents, holds promise for improving patient outcomes.
