Figure 4.

Potential role of metformin in cancer cell killing by immune system regulation. Cells filled red promote tumor survival, while green filled cells are involved in tumor cells killing. Green arrows represent activation of molecules or cells depicted on Figure 4, whereas red lines describes inhibitory interaction between metformin and presented molecules or cells. Red squared boxes show down regulation of specific process by metformin and green squared boxes describe process possibly up-regulated by metformin.