Page 72 - Bio Engineering Approaches to Cancer Diagnosis and Treatment

70 CHAPTER 4 Immunotherapy

4.6.6 Case study ....................................................................................102
4.6.7 Future prospect .............................................................................103
4.7 Nonspecific immunotherapy ............................................................................... 103
4.7.1 Cytokines in nonspecific immunotherapy ..........................................104
4.7.2 Immune checkpoint inhibitors .........................................................106
References ...............................................................................................................108

4.1 Cancer immunotherapy
Cancer is the principal cause of early death worldwide. American Cancer Society has
appraised that nearly 1.7 million new cancer cases and 609,640 deaths happened in
2018 in the US. The mortality rates due to cancer types include lung (1.69 million),
liver (788,000), colorectal (774,000), stomach (754,000), and breast (571,000)
cancers [1]. Common cancer remedies such as tumor surgery, chemotherapy, and
hormonal treatments are subject to limitations. For instance, tumor surgery cannot
inhibit metastasis, and radiation therapy is costly and time consuming. The anti-
cancer drugs in chemotherapy can be rapidly released throughout the body and are
toxic to noncancerous cells. Moreover this approach is ineffective in eliminating
metastatic cancer cells [2].
Thomas and Burnet have demonstrated that the immune system can contribute to
the control and progression of cancer [3]. Cancer immunotherapy has evolved to pro-
mote a cancer-specific immune response to eliminate tumor cells as a new treatment
method. It has been shown that the immune system can suppress tumors by apoptosis
and phagocytosis of cancer cells.
Immunotherapy can be used in the following cases:
• Slowing and inhibiting tumor cell growth
• Prevent cancer from permeating to other organs of the body
• Improving the immune system function in destroying tumor cells
Different types of cancer immunotherapy include blockade of immune check-
points, oncolytic virus therapy, T cell therapy, cancer vaccines, antibody based tar-
geted therapy, and cytokine therapy.

4.1.1 Blockade of immune checkpoints
Blockade of immune checkpoints is the most promising approach in activating
remedial antitumor immunity. Immune checkpoints are described to a plethora of
inhibitory pathways that are essential for retaining self-tolerance and regulating the
duration and amplitude of physiological immune responses in order to reduce tissue
damage. It is now explicit that tumors adjust to certain immune-checkpoint pathways
as the main mechanism of immune resistance, especially against T cells that are char-
acteristic for tumor antigens. Since many of the immune checkpoints are activated
by ligand-receptor interactions, they can be easily blocked by antibodies or regulated