The tumor is an abnormal tissue mass formed when cells divide and grow excessively within the body. Tumors can be benign (not cancerous) or malignant (cancerous). Benign tumors may become larger but do not spread to nearby tissue or other parts of the body. Malignant tumors, on the other hand, can spread nearby to tissue and can also be transmitted to other parts of the body through the blood and or lymphatic system.1 But we are no strangers to tumors and how the develop.

On the other hand, many of us aren’t as familiar with a tumor’s environment. Tumor progression is profoundly affected by the subtle interaction of tumor cells with immune and non-immune cells within their environment. In particular, the interactions with the immune cell component of a tumor are fundamental in determining whether primary tumors are eradicated, metastasized, or established by dormant micro metastases.3 The environment that a tumor grows in is also much more complex than one would think because of its highly variable cell composition, large number of proteins, and structures involved in tumor formation.

This being said, tumor microenvironment includes:
• Heterogeneous populations of cancer cells
• A variety of resident and osmotic host cells
• Secretion factors
• Extracellular matrix proteins