*3.3.2 TGF-β*

The high levels of the immune-inhibitory cytokine (TGF-β) are associated with multiple types of immune deficiency diseases, resistant, and metastatic types of cancer (i.e. CC). This cytokine can be secreted from the tumor-associated macrophages and resistant cancer cells to induce the T-regulatory cells that will inhibit the activation of the CTL and TH cells. As a result, the CTL and TH cells cannot recognize cancer cells to induce apoptosis or their engulfment by the phagocytic cells [2, 18, 22, 33].

On the other hand, TGF-β enhances the VEGF secretions from the cancer cells. The VEGF amplifies the vasculature, the proinflammatory status, and the wound healing environment around the cancerous tissue. As a result, this can promote the cancer growth, metastasis, and activation of the tumor-associated macrophages to escape the immune surveillance for cancerous tissue [22, 25, 34].
