Tumor Immunology Tumor antigens Classification of tumor antigens Tumors Immunotechnology Cancer Tumor-specific antigens (TSAs) Tumor-associated antigens (TAAs)

1. Tumor Immunology
Kandati Kusuma

2. Introductio
n
Tumor immunology is the study of how the immune system interacts with
cancer cells.
The immune system is responsible for recognizing and eliminating foreign or
abnormal cells in the body, including cancer cells. However, cancer cells can
evade immune detection and destruction by developing mechanisms to
suppress the immune system or by presenting themselves as normal cells.
The field of tumor immunology aims to understand the complex interactions
between cancer cells and the immune system in order to develop strategies to
enhance the immune system's ability to recognize and attack cancer cells.
This includes studying the role of various immune cells such as T cells, B cells,
natural killer cells, cytokines, and chemokines, in cancer development and
progression.

3. Researchers in tumor immunology also
investigate the use of immunotherapies, which
are treatments that use the body's own
immune system to fight cancer.
Examples of immunotherapies include
checkpoint inhibitors, which block proteins that
prevent the immune system from attacking
cancer cells, and CAR-T cell therapy, which
involves genetically engineering a patient's T
cells to recognize and kill cancer cells.

5. Cancer
Cancer is a group of diseases characterized by the uncontrolled growth and
proliferation of abnormal cells in the body.
These abnormal cells, also known as cancer cells, can invade and damage
nearby tissues and organs, and can also spread to other parts of the body
through the bloodstream or lymphatic system, forming new tumors in a
process known as metastasis.
There are many different types of cancer, each with their own specific
characteristics and treatment options.
Some common types of cancer include lung cancer, breast cancer, prostate
cancer, and colon cancer.

6. • The causes of cancer are complex and can vary depending on the type of cancer.
• Some risk factors for cancer include genetics, exposure to certain chemicals or radiation, unhealthy
lifestyle choices such as smoking and poor diet, and infections such as HPV or hepatitis B and C.
• Cancer treatment options may include surgery, radiation therapy, chemotherapy, immunotherapy,
and targeted therapy.
• The choice of treatment depends on the type and stage of cancer, as well as the patient's overall
health and preferences.
• Prevention of cancer involves adopting healthy lifestyle habits such as regular exercise, maintaining
a healthy weight, avoiding tobacco and excessive alcohol consumption, and getting regular
cancer screenings.
• Early detection and treatment are important in improving the outcomes of cancer patients.

7. Tumor antigens
• Tumor antigens are substances that are found on the surface of cancer cells or are produced by the
cancer cells themselves.
• They are recognized as foreign by the immune system, which triggers an immune response to
attack and eliminate the cancer cells.
• There are two main types of tumor antigens: Tumor-specific antigens (TSAs) and Tumor-
associated antigens (TAAs).
• TSAs are unique to cancer cells and are not expressed in normal cells, while TAAs are also found in
normal cells but are overexpressed or mutated in cancer cells.
• TSAs are ideal targets for cancer immunotherapy because they are specific to cancer cells and can
elicit a strong immune response against cancer cells.
• Examples of TSAs include the NY-ESO-1 antigen found in some melanoma, lung, and ovarian
cancers, and the MAGE-A3 antigen found in some melanoma and lung cancers.

8. • TAAs, on the other hand, are less specific to cancer cells and can sometimes also be found in
normal cells, which can make it more challenging to target them without damaging healthy tissue.
• However, some TAAs can still be effective targets for immunotherapy, especially if they are highly
expressed in cancer cells.
• Examples of TAAs include the HER2 antigen found in some breast and ovarian cancers, and the PSA
antigen found in prostate cancer.
• Tumor antigens are important targets for cancer immunotherapy, including treatments such as
cancer vaccines, adoptive T cell therapy, and checkpoint inhibitors.
• By targeting tumor antigens, these therapies can help the immune system recognize and attack
cancer cells, leading to improved outcomes for cancer patients.

9. Classification of Tumor antigens
• Tumor antigens can be classified into several categories based on their origin, expression, and
function.
• The following are the main types of tumor antigens:
• Tumor-specific antigens (TSAs): TSAs are unique to cancer cells and are not expressed in normal
cells. They arise from genetic mutations or aberrant expression of normally silent genes. TSAs are
attractive targets for cancer immunotherapy because they are highly specific to cancer cells and do
not cross-react with normal tissues.
• Tumor-associated antigens (TAAs): TAAs are antigens that are overexpressed or aberrantly
expressed in cancer cells, but are also present in normal cells at lower levels. They can be divided
into several subtypes based on their cellular localization and expression patterns. Examples include
cell surface antigens, cytoplasmic antigens, and nuclear antigens.

10. • Cancer-testis antigens (CTAs): CTAs are a subset of TAAs that are expressed in a variety of cancer
types, but are normally restricted to germ cells in the testes. Examples of CTAs include MAGE-A and
NY-ESO-1.
• Differentiation antigens: Differentiation antigens are antigens that are expressed on both normal
and cancer cells, but at different levels. They are involved in the process of cellular differentiation
and can be used as markers to identify specific types of cancer cells.
• Viral antigens: Some tumors are caused by viral infections, such as human papillomavirus (HPV) or
hepatitis B virus (HBV). Viral antigens expressed by these tumors can be targeted by
immunotherapy.
• Understanding the classification of tumor antigens is important for developing effective
immunotherapies that can selectively target cancer cells while sparing normal tissues. By
identifying the specific types of tumor antigens expressed by different cancers, researchers can
develop targeted therapies that can improve the outcomes of cancer patients.

26. • A number of viruses cause different types of tumors
in animals (for example, SV-40 virus, adenovirus,
Rous sarcoma virus, Friend erythroleukemic virus,
Moloney Rauscher and Gross viruses).
• Viruses are involved or suspected to be involved in
some human malignancies (HTLV-1 in leukemia,
hepatitis-B virus in hepatic carcinoma, papilloma
virus in cervical cancer).
• Virus-induced tumors express cell surface antigens
(distinct from antigens of the virion itself) which are
shared by all tumors induced by the same virus.
• These antigens are characteristic of the tumor-
inducing virus, regardless of tissue origin of the
tumor or animal species in which the tumor exists
Virus

27. • Viruses can cause tumors in animals and humans by integrating their genetic material into the host
cell's DNA, which can lead to uncontrolled cell growth and division.
• The viruses such as SV-40 virus, adenovirus, Rous sarcoma virus, and papillomavirus, are examples of
oncogenic viruses that are known to cause tumors in animals and humans.
• When a virus induces a tumor, the tumor cells can express cell surface antigens that are not present
on normal cells.
• These antigens are often shared by all tumors induced by the same virus, regardless of the tissue of
origin or animal species in which the tumor exists.
• These viral-induced tumor antigens are often specific and can be used as targets for immunotherapy
or as diagnostic markers for the presence of the virus or tumor.
• For example, human papillomavirus (HPV) is known to cause cervical cancer, and the expression of
viral antigens on the surface of tumor cells has been used to develop HPV-specific vaccines and
diagnostic tests.
• Similarly, hepatitis B virus (HBV) is associated with liver cancer, and the expression of HBV antigens
on the surface of tumor cells can be used for diagnosis and monitoring of the disease.

28. • Chemically-induced tumors are
different from virally-induced
tumors in that they are
extremely heterogeneous in
their antigenic characteristics.
• Thus, any two tumors induced
by the same chemical, even in
the same animal, rarely share
common tumor-specific
antigens.
• These unique antigens on
chemically-induced tumors are
referred to as tumor-specific
transplantation antigens (TSTA).
Chemical agents/Physical agents

29. • Chemically-induced tumors differ from virally-induced tumors in that they are highly heterogeneous and do not share common
tumor-specific antigens. This is because chemical carcinogens can cause mutations in the DNA of cells, leading to a wide range of
genetic and epigenetic changes that can result in highly diverse tumor cell populations.
• Unlike viral-induced tumors, which express shared viral antigens that can be used for immunotherapy or diagnostic purposes,
chemically-induced tumors may express unique antigens that are specific to the individual tumor. These unique antigens are
referred to as tumor-specific transplantation antigens (TSTAs), and they can be used as targets for immunotherapy, as well as for
identifying and characterizing individual tumors.
• The heterogeneity of chemically-induced tumors makes it challenging to develop effective immunotherapies that can target all
tumor cells. However, recent advances in cancer immunotherapy have shown promise in developing personalized treatments that
can target unique antigens expressed by individual tumors. These approaches include adoptive cell transfer therapy, where T cells
are isolated and expanded from a patient's own tumor, and chimeric antigen receptor (CAR) T-cell therapy, where T cells are
genetically modified to express receptors that target specific tumor antigens.