Tumor Immunology objectives

Question 1

List the three immunological processes that lead to destruction of tumors

Answer 1

1. Opsonin Mediated Phagocytosis
2. Natural Killer Cells
3. Cytotoxic T cells

Question 2

Tumors evasion of the immune system can be classed as (A) T cell defects, (b) Tumor related phenomenon. List five T cell defects related to phenomenon that leads to tumor evasion of the immune system

Answer 2

1. Hole in the repertoire
2. Lack of the costimulatory molecules
3. Lack of Type 1 cytokine
4. Lack of Th17 cells
5. Increase in Tregs

Question 3

List the 10 tumor related phenomenons that lead to tumor evasion of the immune system?

Answer 3

1. Shedding of tumor antigens
2. antigenic modulation (Endocytosis)
3. antigen masking
4. loss of antigenicity (tumors not seen as foreign)
5. Secretion of Immunosuppressive Molecules
6. Immunology Privileged Site
7. Loss of class I MHC expression
8. Shed MICA
9. Upregulation of CD200
10. Upregulation of PD-L1/L2

Question 4

Contrast benign and malignant tumors

Answer 4

Benign –> encapsulated tumors whose cells are well differentiated and resemble normal tissues
Malignant tumor –> not encapsulated but has the capacity to invade adjacent tissue locally, and ultimately spread to distant sites; undifferentiated with high proliferative capacity causing tumor growth

Question 5

Compare benign and malignant tumors

Answer 5

Regardless of the biology of tumor development, eradication of tumors by the immune system requires recognition of something (an antigen) unique to the tumor, which is not expressed by normal tissue.

Question 6

List the particular malignancies that arise in immunosuppressed patients or in patients that are using immunosupressive drugs

Answer 6

In individuals who are immunosuppressed only the frequency of lymphomas, skin cancers and Kaposi’s sarcomas was increased

Question 7

List the particular malignancies that arise in patients with Epstein Barr Virus

Answer 7

Epstein Barr Virus infection of B cells (causing mononucleosis, a self limiting disease, in the general population) can lead to B cell lymphoma (Burkitt’s lymphoma) in immunosuppressed individuals

Question 8

List the particular malignancies that arise in patients with HIV virus

Answer 8

patients with AIDS often develop Kaposi’s sarcoma, following exposure to herpes simplex virus (HSV-8), which is non tumorigenic in normal individuals

Question 9

List one tumor specific antigens and the malignancy with which it is associated with

Answer 9

Tumor Specific Antigen–> mIg present on a B cell monoclonal tumor
Malignancy –> Chronic lymphocytic leukemia (CLL)

Question 10

Carcinoembryonic antigen (CEA), alpha-fetoprotein (alphaFP), and beta human chorionic gonadotropin, (B-HCG) are oncofetal antigens that are classified as tumor associated antigen. Explain the term tumor associated

Answer 10

Tumor associated antigens (TAAs) –> can be used to characterize tumors, but are not necessarily unique to the tumor opposed to other (normal) host tissue. Often reflect antigens expressed at stages of normal cell differentiation although not the same quantity or quality

Question 11

Specify the tumors in which each tumor associated antigen is present

Answer 11

1. Carcinoembryonic Antigen (CEA) –> colon tumors (With high levels being found in cigarette smokers)
2. Alpha-Fetoprotein (AlphaFP) –> increased serum levels are secreted by hepatoma cells. Viral and alcoholic cirrhosis of the liver also have elevated levels; liver and testicular tumors
3. Beta-HCG—> Gonadal germ cell tumors produce this. these tumors arise in the testicles in men and ovaries in women. Choriocarcinoma (cancer of the placenta) the decline in B-HCG monitors therapy

Question 12

Tumor markers play a role in tumor immunology. List four tumor markers and the malignancy with which each is associated as well as their role in diagnosis.

Answer 12

Tumor markers are expressed in minor amounts.

1. Her-2 (human epidermal growth factor receptor 2) encodes a transmembrane tyrosine kinase receptor that is now considered an indicator of breast cancer.
2. MAGE 1-3 are melanoma antigens. (melanaA/MART-1 –> also does melanomas)
3. NY-ESO-1 –> Human tumors, including melanoma
4. 17-1A –> Colon carcinoma

Question 13

Describe lymphoma

Answer 13

Malignancy that begins in cells of the immune system
two types: hodgkin’s lymphoma (Reed Sternberg cell) and non hodgkin’s (Encompasses a diverse group of cancers of cells present in the immune system)

Question 14

Describe leukemia

Answer 14

Malignancies that start in the bone marrow resulting in a excessive number of blood cells that enter the blood stream.
May be acute or chronic
May be T cell or B cell lymphoblasts

Question 15

Describe Plasma Cell

Answer 15

Malignancy that begins in the plasma cells and includes multiple myeloma and Waldenstroma’s

Question 16

Describe multiple myeloma

Answer 16

begins in the plasma cells in bone marrow. plasma cells grow out of control and form tumors in the areas of solid bone
Bence Jones Proteins (immunoglobulin light chains) in urine