Cancer Advisor

Cancer Advisor  |  Updated September 19, 2026 The tumor microenvironment (TME) is the biological ecosystem surrounding a tumor. It includes immune cells, cancer-associated fibroblasts (CAFs), blood and lymphatic vessels, extracellular matrix, signaling molecules, nutrients, metabolites, oxygen gradients and physical conditions such as tissue stiffness, acidity and abnormal interstitial pressure. Modern oncology increasingly recognizes that cancer is not simply a collection of malignant cells. Tumor cells continuously interact with their surrounding tissue, while the surrounding tissue can influence tumor growth, invasion, metastasis, immune surveillance, drug delivery and treatment response. The National Cancer Institute defines the TME broadly as the normal cells, molecules and blood vessels surrounding and feeding a tumor, and notes that tumors can change their microenvironment while the microenvironment can influ...

Quick Answer “Cold” and “hot” tumors describe how visible a cancer is to the immune system. Hot tumors have strong immune cell infiltration and are more likely to respond to immunotherapy. Cold tumors lack immune visibility and are more resistant. However, recent research shows this is an oversimplification. Tumors exist along a spectrum of immune states, shaped not only by genetics (PD-L1, TMB, MSI-H) but also by the tumor microenvironment, including immune exclusion, metabolism, and stromal barriers. Modern immunotherapy success depends on both tumor genetics and immune ecosystem structure. Key Takeaways Tumors are not simply “cold” or “hot” but exist on an immune spectrum. Hot tumors usually respond better to PD-1/PD-L1 checkpoint inhibitors. Cold tumors often resist immunotherapy due to lack of immune infiltration. Immune-excluded tumors have immune cells at the edges but not inside. Immune-desert tumors lack meaningful immune presence entirely. Tumor microenvironment factors (stro...

Metabolic Oncology • Tumor Microenvironment • Repurposed Medicine Cancer is not simply a mass of malignant cells. In some tumors—especially pancreatic ductal adenocarcinoma—the cancer grows inside a dense, fibroinflammatory ecosystem that can influence blood flow, drug delivery, immune activity and treatment resistance. This article examines whether repurposed drugs and selected supplements could help remodel rather than simply destroy this protective tumor microenvironment. Desmoplasia Cancer-associated fibroblasts Tumor microenvironment Pancreatic cancer Repurposed drugs Vitamin D Important: This is an educational review of cancer biology and emerging research. Repurposed drugs and supplements discussed here should not be considered established cancer treatments or substitutes for evidence-based oncology. Some are prescription medicines, may have important interactions or toxicities, and should only be considered with a...