Cancer vaccines work by stimulating the immune system to fight cancer. There are two types - preventive vaccines which prevent cancer, and therapeutic vaccines which treat existing cancer. Cancer vaccines include tumor cell vaccines using whole tumor cells, dendritic cell vaccines using dendritic cells presenting tumor antigens, antigen vaccines targeting specific tumor antigens, and DNA vaccines introducing tumor genes to stimulate an immune response. Early studies show some lung cancer patients receiving a dendritic cell vaccine had antigen-specific immune responses. While promising, more research is still needed to fully realize the potential of cancer vaccines.

1. Cancer vaccines
Muhammad Uzair Shah Hashmi
Ug-3, ASAB
NUST, H-12
Submitted To : Dr. Sadia Rashid

2. Cancer vaccines
Cancer vaccines are medicines that belong to a class of substances known as biological response
modifiers. Biological response modifiers work by stimulating or restoring the immune system’s
ability to fight infections and disease.
Two broad types of cancer vaccines
•Preventive (or prophylactic) vaccines
prevent cancer from developing in healthy people.
•Treatment (or therapeutic) vaccines
treat an existing cancer by strengthening the body’s natural defenses against the cancer.
Lollini PL, Cavallo F, Nanni P, Forni G. Vaccines for tumour prevention. Nature Reviews Cancer2006; 6(3):204–216.

3. Antitumor response of prophylactic vaccine
• Given to people who have very high risk of developing cancers that have
been diagnosed with premalignant changes in tissues
• Vaccine based antigen along with immunomodulatory is introduced that
activate the Langerhan's cells.
• T cells are activated when the tumor antigen is presented to them along
with B cells that produce tumor specific antibodies
• Clonal expansion is the next process that occurs along with the memory
cell formation.
• In future if tumor start its growth tumor specific memoray cells wil be
reactivated by the tumor antigen reaching lymph nodes
• Secondary immune response
1. Large no of effector T cells
2. High titer of antibodies
3. Continues activation of DC at the site
• Tumor will not be allowed to grow large and is easiy eliminated as a
result of secondary immune response.
http://fog.its.uiowa.edu/~immuno/classMaterial/Advanced%20Topics%202004/Sept29Session%2011/Olivera.pdf

5. Anti tumor response of therapeutic vaccine
• Administered after tumor diagnosis when tumor is interacting with
immune system.
• Vaccine (autologous/defined tumor antigen + immunomodulators) to
activate Langerhan’s cells.
• Taken up by activated Langerhan's cells and presented to T cells
• B-cell activated, clonal expansion, production of tumor specific antibodies.
• Migration of tumor sensitive T cells at site of tumor metastasis.(attempt to
kill tumor cells expressing vaccine Ag.)
• Immunosuppressive tumor microenvironment suppresses their function.
• Establishment of tumor heterogeneity. Leading to lost of tumor antigen
expression or resistance immune effectors mechanism evading immune
evasion.
• Tumor cells with antigen not recognized by T-cells and Ab. They are
resistant to immune destruction.
http://fog.its.uiowa.edu/~immuno/classMaterial/Advanced%20Topics%202004/Sept29Session%2011/Olivera.pdf

7. Cancer vaccine types
• Tumor cell vaccines
Utilizes whole tumor cells rendered safe by irradiation.
-Autologous vs. Allogenic
• Dendritic cell vaccines
Dendritic cells can be generated outside of the body. Cancers these vaccines
are being studied in: prostate, melanoma, breast, lung, colorectal, kidney,
leukemia, and non-Hodgkin lymphoma
• Antigen vaccines
This includes peptide vaccines: only one specific epitope is injected.
Cancers these vaccines are being studied in include: kidney cancer,
pancreatic cancer, melanoma, ovarian cancer, breast cancer, prostate
cancer, and colorectal cancer.
http://oncolink.org/treatment/article.cfm?c=11&s=80&id=252

8. Types contd…
• Anti-Idiotype vaccines
• Based on the idea that antibodies can also act as antigens triggering
an immune response. This idea would be used to create a vaccine in
which the antibodies (which resemble the cancer cells) would be
injected into the cancer patient eliciting an immune response.
• DNA Vaccines
• Introduction of tumor genes instead of tumor antigen itself.
• Cells in the body take up the injected DNA. Specific antigens would
then be made on a continuous basis.
• The idea of these vaccines is that the body would be provided with
a constant supply of antigens to allow the immune response to
continue against the cancer.
• Cancers these vaccines are being studied in: prostate cancer,
leukemia, melanoma, and head and neck cancer.
http://oncolink.org/treatment/article.cfm?c=11&s=80&id=252

9. Lung Cancer Vaccine at UK
• Dendritic cell vaccine.
• Treatment of non-small cell lung cancer (NSCLC).
• Study: Patients with Stage IA to IIIB were given vaccine.
• Patients treated prior with surgery, chemoradiation, or
multimodality therapy.
• Results published for 16 patients.
~5/16: no clear immunologic response.
~5/16: antigen-independent response.
~6/16: response may have been tumor specific.
~response shown in various stages of NSCLC.

10. Conclusion
• Clear that the immune system displays a highly developed
response against cancer.
• May be more effective in cancers that are not advanced.
• Majority will probably be used as adjuvants.
• Clinically not yet at our fingertips.
• Much progress has been made in this area of research.
• More research still needs to be done including larger
studies.
• Researchers are actively trying to overcome hurdles in the
making of these vaccines.
• Could make a big impact on our approach to cancer.
• Most importantly these vaccines could mean better
quality of life and longer survival for our patients!!