Cancer Advisor | One Day MD

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...

One of the most powerful predictors of immunotherapy response is Microsatellite Instability-High (MSI-H). Patients with MSI-H cancers frequently experience response rates that exceed those seen in many traditional cancer treatments. What Is MSI-H? Microsatellites are short repeating DNA sequences. Normally, cells repair DNA replication errors using the mismatch repair (MMR) system. When this repair system fails: Mutations accumulate rapidly. Genetic instability increases. MSI-H develops. The Mismatch Repair System Key repair genes include: MLH1 MSH2 MSH6 PMS2 Defects in these genes create: dMMR (deficient mismatch repair) MSI-H tumors Why MSI-H Tumors Respond to Immunotherapy MSI-H tumors accumulate thousands of mutations. This generates: Large numbers of neoantigens Strong immune recognition Increased T-cell infiltration These tumors are often considered naturally "hot." Cancers Commonly Associated with MSI-H Colorectal cancer Endometrial cancer Gastric cancer Small bowel ca...

Quick Answer Tumor Mutation Burden (TMB) measures the number of genetic mutations within a cancer's DNA. Tumors with a high TMB often produce more abnormal proteins (neoantigens), making them easier for the immune system to recognize and attack. As a result, patients with high-TMB tumors may be more likely to benefit from immune checkpoint inhibitors such as pembrolizumab, nivolumab, and ipilimumab. However, TMB is not a perfect biomarker. Some patients with high TMB fail to respond to immunotherapy, while others with low TMB experience remarkable and durable responses. Key Takeaways TMB measures the number of mutations within a tumor. High-TMB tumors tend to generate more neoantigens. More neoantigens may increase immune recognition. High TMB is associated with improved responses to some immunotherapies. The FDA has approved immunotherapy for certain high-TMB cancers. TMB should be interpreted alongside PD-L1, MSI-H status, and other biomarkers. TMB is an important component of pr...

Immunotherapy has transformed cancer treatment, producing remarkable responses in some patients while offering limited benefit to others. One of the most important biomarkers helping doctors predict who may benefit is Tumor Mutation Burden (TMB). TMB measures the number of genetic mutations present within a tumor. The theory is simple: tumors with more mutations create more abnormal proteins that the immune system can recognize as foreign. Today, TMB testing is increasingly used alongside PD-L1 expression, microsatellite instability (MSI), and other biomarkers to guide immunotherapy decisions. What Is Tumor Mutation Burden? Tumor Mutation Burden refers to the total number of mutations found within a tumor's DNA. A tumor with: High TMB contains many mutations. Low TMB contains relatively few mutations. Mutations can create abnormal proteins called neoantigens. These neoantigens may act like "flags" that make cancer cells easier for immune cells to identify and attack. Why ...

If you've recently been diagnosed with cancer, your doctor may order a PD-L1 test. Many patients receive a PD-L1 score but have little understanding of what it means. What Is PD-L1? PD-L1 stands for Programmed Death-Ligand 1. It is a protein found on some cancer cells. PD-L1 can bind to PD-1 receptors on immune cells and essentially tell them: "Don't attack me." This allows tumors to evade immune destruction. How Immunotherapy Targets PD-L1 Checkpoint inhibitors block this interaction. Examples include: Pembrolizumab Nivolumab Atezolizumab Durvalumab These drugs remove the "brakes" on the immune system. Understanding PD-L1 Scores Testing may report: TPS (Tumor Proportion Score) CPS (Combined Positive Score) Generally: Higher scores often predict better responses. Lower scores do not necessarily mean treatment won't work. Cancers Commonly Tested Non-small cell lung cancer Triple-negative breast cancer Head and neck cancer Bladder cancer Esophageal cancer ...

Among all cancer treatments, immunotherapy has produced some of the most extraordinary responses ever documented. Patients with advanced cancers occasionally experience dramatic tumor shrinkage that appears almost miraculous. Why does this happen? The Power of the Immune System Unlike chemotherapy, immunotherapy does not directly attack cancer cells. Instead, it activates the patient's own immune system. When successful, immune cells can: Seek out cancer throughout the body Adapt over time Develop long-term memory Common Features of Exceptional Responders Research suggests exceptional responders often have: High Tumor Mutation Burden More mutations create more targets. MSI-H Status Strong immune visibility. Hot Tumors Pre-existing immune infiltration. Favorable Gut Microbiome Emerging evidence suggests gut bacteria influence treatment response. Strong T-Cell Activity More active immune systems may produce deeper responses. The Abscopal Effect Occasionally radiation therapy triggers...