Tumor Microenvironment and Immune Inhibitory Pathways

Illustration of the tumor microenvironment showing the immune desert in which the immune system does not recognize the tumor.

Tumor Microenvironment Immune Desert

Illustration of the tumor microenvironment showing the use of PD-L1 by the tumor to exclude the immune system cells.

Tumor Microenvironment Immune Exclusion Pathway

Illustration of the tumor microenvironment showing the changes caused by the infiltration of immune system cells into the tumor.

Tumor Microenvironment Immune Infiltration Pathway


Adobe Illustrator

Immuno Oncology Researchers

Print and online


Purpose of illustration

The purpose of this series of illustrations was to explain the tumor microenvironment. The microenvironment varies depending on which immune inhibitory pathways are present. Understanding these pathways is vital in cancer research, pathology, diagnosis and ultimately treatment.

The first illustration shows the tumor in an immune desert in which the tumor is hiding in plain sight and is simply undetected by the immune system. There is no army of T cells mounting an immune system attack to destroy the tumor and it is free to grow and spread unchecked.

The second illustration shows the tumor in an immune excluded environment. PD-L1 (programmed death-ligand 1) proteins are represented as the orange colored barrier surrounding the tumor. There are immune cells represented outside the tumor, but the PD-L1 prevents them from mounting an attack on the cancer cells. PD-L1 can be found on the surface of some types of cancer cells. The cancer cells use PD-L1 proteins to hide from the immune system.

The third illustration shows an engaged immune system. Infiltration of the tumor is represented by activated lymphocytes highlighted with an orange glow. These activated immune cells then bring in macrophages (in purple) and dendritic cells (in green), which assist in destroying the cancer cells.

Finally, viewing all three of these scenarios together helps explain the tumor microenvironment in very broad strokes. There are a lot of ways to represent this subject, and the client was looking for an interesting and different approach. The intended audience is well versed in the science of the subject, so a bit of creative license could be exercised to create visual interest.

What is the tumor microenvironment?

The tumor microenvironment is the collection of the cells that make up a cancerous tumor and all the surrounding tissues, including blood vessels, inflammatory or immune cells and normal tissue. In simple terms, it is the neighborhood in which a cancerous tumor is living. Being able to identify the individual cell types present in the microenvironment can play a big role in diagnosis, treatment and predicting outcomes.

Artists comments

This project was an interesting and fun challenge. This was my first experience using the 3D capabilities of Adobe Illustrator. It opened up some new possibilities for the project, but it also created some unexpected design difficulties. A strategy game called Settlers of Catan was the inspiration for the design of the hexagonal game board tiles. Designing the cellular patterns on them was challenging, especially when a cell passed between 2 tiles. The PD-L1 and immune cells went through several stages to arrive at the final design. Overall, I think it works well, and is a very unusual presentation of this subject. I hope to use more 3D elements in future projects if possible.