Cancer Immunotherapy Exam questions and
answers
cancer immunotherapy history
- 1890s - coley - mixing toxins and injecting into patient causing cancer regression but not all people
responded to toxin, taken over by radiation therapy
- 1909 - ehrlich - theory that cancer would increase without the immune system
- 1950s - thomas & burnet - immunosurveillance and immunoediting --> immune system can eradicate
cancer cells by detecting them
- 2001 - other observations
- immunosuppressed mice, HIV/AIDS patients, organ transplant patients have higher rate of cancer
- cancer patients with increased T cell at tumor site have better overall survival
(t/f) cancer immunotherapy was the first treatment for cancer
true
thomas & burnet - immunosurveillance and immunoediting
- 3 stages
1. elimination - tumor suppression
2. equilibrium - tumor dormancy and editing (cannot completely eradicate but not yet uncontrolled
growth)
3. escape - tumor growth promotion (mutation in APC overcomes immune system)
- PD-L1, PD-1 and CTLA-4 play an important role (sites/targets for immune therapy to boost immune
system)
immune system function and immune response
- identify and destroy foreign or abnormal cells in the body (ex. cancer cells)
- innate immunity present when you are born
- innate immunity primes to activate adaptive immunity after
- early immunotherapy efficacy was only 20-30% of patients (but can consider close to a cure - strong
response)
- new is 60-80% efficacy
immune surveillance
, - involves both innate and adaptive immune mechanisms
- tumor-associated antigens can be identified by the immune system and destroyed
- goal of immunotherapy for cancer: to "educate and liberate" underlying anticancer immune
responses
how cancer cells evade the immune system
1. decrease tumor immunogenicity - eliminate expression of antigens or continue to grow cancer clones
without antigens --> immune system cannot recognize cancer cells
2. inhibit dendritic cell maturation and antigen presentation - via production of cytokines
3. suppress T cell activation (change MHC)
4. inhibit T cell migration and infiltration
5. inhibit recognition by immune cells - cancer cell activates inhibitory protein and T cells not effective at
recognizing cancer cells
6. increase immune checkpoint molecules - we have immune checkpoint inhibitors (treatment that
addresses this)
7. increase in immunosuppressive cells
(t/f) dendritic cells are APCs
true; process antigens on cancer cells so they can teach T cells to recognize cancer cells as foreign and
eliminate them
cancer immunity cycle
- cancer cells can die through natural cell death - release of antigens
- antigens recognized by dendritic cells and present via MHCI or II to T cells
- trafficking of T cells to tumor and infiltrate/bind to cancer cell
- tumor cell dies
- causes more cancer cells to die and more release of antigens (cyclic)
goal of cancer immunotherapy
- harness, strengthen, and sustain the power of the immune system
- augment the patient’s own immune system to fight cancer
- activate the immune system
- inhibit immunosuppression
- avoid autoimmunity - sometimes targets on cancer cells are the same as targets on normal cells
answers
cancer immunotherapy history
- 1890s - coley - mixing toxins and injecting into patient causing cancer regression but not all people
responded to toxin, taken over by radiation therapy
- 1909 - ehrlich - theory that cancer would increase without the immune system
- 1950s - thomas & burnet - immunosurveillance and immunoediting --> immune system can eradicate
cancer cells by detecting them
- 2001 - other observations
- immunosuppressed mice, HIV/AIDS patients, organ transplant patients have higher rate of cancer
- cancer patients with increased T cell at tumor site have better overall survival
(t/f) cancer immunotherapy was the first treatment for cancer
true
thomas & burnet - immunosurveillance and immunoediting
- 3 stages
1. elimination - tumor suppression
2. equilibrium - tumor dormancy and editing (cannot completely eradicate but not yet uncontrolled
growth)
3. escape - tumor growth promotion (mutation in APC overcomes immune system)
- PD-L1, PD-1 and CTLA-4 play an important role (sites/targets for immune therapy to boost immune
system)
immune system function and immune response
- identify and destroy foreign or abnormal cells in the body (ex. cancer cells)
- innate immunity present when you are born
- innate immunity primes to activate adaptive immunity after
- early immunotherapy efficacy was only 20-30% of patients (but can consider close to a cure - strong
response)
- new is 60-80% efficacy
immune surveillance
, - involves both innate and adaptive immune mechanisms
- tumor-associated antigens can be identified by the immune system and destroyed
- goal of immunotherapy for cancer: to "educate and liberate" underlying anticancer immune
responses
how cancer cells evade the immune system
1. decrease tumor immunogenicity - eliminate expression of antigens or continue to grow cancer clones
without antigens --> immune system cannot recognize cancer cells
2. inhibit dendritic cell maturation and antigen presentation - via production of cytokines
3. suppress T cell activation (change MHC)
4. inhibit T cell migration and infiltration
5. inhibit recognition by immune cells - cancer cell activates inhibitory protein and T cells not effective at
recognizing cancer cells
6. increase immune checkpoint molecules - we have immune checkpoint inhibitors (treatment that
addresses this)
7. increase in immunosuppressive cells
(t/f) dendritic cells are APCs
true; process antigens on cancer cells so they can teach T cells to recognize cancer cells as foreign and
eliminate them
cancer immunity cycle
- cancer cells can die through natural cell death - release of antigens
- antigens recognized by dendritic cells and present via MHCI or II to T cells
- trafficking of T cells to tumor and infiltrate/bind to cancer cell
- tumor cell dies
- causes more cancer cells to die and more release of antigens (cyclic)
goal of cancer immunotherapy
- harness, strengthen, and sustain the power of the immune system
- augment the patient’s own immune system to fight cancer
- activate the immune system
- inhibit immunosuppression
- avoid autoimmunity - sometimes targets on cancer cells are the same as targets on normal cells
