Different types of immune cells play an important role in the tumor microenvironment (TME). This means they can affect how cancer grows and how well treatments work. Here are some key immune cells involved:

1. Tumor-Infiltrating Lymphocytes (TILs):

   • CD8+ T cells can help fight against tumors.
   • These cells make up about 30% of lymphocytes in some tumors.
   • When there are more TILs present, patients tend to live longer, sometimes with a 50% increase in 5-year survival rates.

2. Regulatory T cells (Tregs):

   • Tregs often reduce the body's anti-tumor responses.
   • If there are 2-3 times more Tregs, it usually means a poorer outlook for the patient.

3. Macrophages:

   • M2-polarized macrophages can help tumors grow and spread, forming about 50% of the immune cells in the TME.

4. Dendritic Cells (DCs):

   • DCs help activate T cells to fight cancer.
   • If there are fewer mature DCs, the immune response can weaken.

These interactions in the TME show us that the immune system can either help or hurt the growth of tumors.