Question

In general, how does the immune system respond to cancer?  

4.    Why does radiation therapy often lead to hair loss and skin problems?

5.    Discuss the use of non-steroidal anti-inflammatory drugs (NSAIDS) in the treatment of chronic pain

6.  Describe several ways cancer/cancer cells evade the immune system

7. In the past decade, many investigations recorded heightened interest in immunotherapy      

       a. What is immunotherapy?   

b.   Imagine you are an immunologist presented with the task of using immunotherapy for Dexter’s           

      cancer.   Devise an experimental plan for course of treatment.

Answer 1

4. Radiation therapy often leads to hair loss and skin problems because radiation is a non0discriminatory treatment, it does not distinguish between cancer and normal cells. Also it is impossible to irradiate and kill each cancer ccell specifically so collateral damage occurs.

Hairloss or epilation is temporary when radiation is frationally dosed but can be permanent if doses larger than 10 Gray are administered. The skin becomes pink and sore under radiation but recovery is generally quick.

5. NSAID's like Ibuprofen and Naproxen are used to reduce pain, prevent blood clots and reduce inflammation. They work by inhibiting the activity of cyclooxygenase enzymes (COX -1 & COX - 2) thereby inhibiting prostaglandins in the body which cause inflammations and thromboxanes which induce blood clotting. They work effectively but excess NSAID intake can lead to internal bleeding (as they are good blood thinners like Asprin) and in some cases thrombosis or internal clotting which may lead to heat attacks or haemorrages.

6. The ways cancer cells evade the immune system are -

• Cancer cells are able to block the gene expression of NLRC5 which makes them undetecctable by the immune system.
• Cancer cells produce high levels of a transmembrane protein called CD47 which binds to the SIRPalpha sites on macrophages which makes them harmless towards cancer cells.
• Checkpoint pathways like PD-1 and CDLA-4 prevent marcrophages from attacking tumor cells.
• NK cells detect cancer cells when they are dividing based on the signals released by the cancer cells but are unable to detect cancer cells not dividing. This is one reason recurrence occurs.

7. a) Immunotherapy is the treatment of a disease using substances that enhance the immune response. The substance may be either adjuvants that enhance an immune response or may be foreign particles against which an immune response has to be created.

b) Let us assume that Dexter is diagnosed with Melanoma. To selectively treat the tumors using immunotherapy requires us to identify the properties of the melanomic cells and sites of tumor development. To understand the intensity and stage of the disease, a biopsy has to be conducted. The melanomic cells can be cultured invivo and incubated with various antibodies to find one that kills the tumor cells.One approach can be to design antibodies against Mitogen activated protein kinase or MAPK/ERK pathway. The synthesis of this facter is very high in metastatic melanoma. Once the structure of the antibody is deduced. Monoclonal antibodies can be manuactured synthetically and Dexter can be treated wtih periodic low doses with recovery periods. Melanoma tumors can be potentially eradicated from his body.