The idea is to use the CRISPR technology to tweak prostate cancer cells so that they build up a specific type of compound (called porphyrins) that is usually harmless unless exposed to certain types of light.
In people with a condition called porphyria, these porphyrins naturally build up because of a genetic issue and can cause problems when the skin is exposed to sunlight. The researchers are trying to recreate this condition in cancer cells by shutting down a specific gene responsible for processing these compounds, causing the porphyrins to accumulate.
Once these compounds build up in the cancer cells, exposing them to a special light makes the porphyrins toxic to the cells, effectively killing them. This method targets only the cancer cells, leaving healthy cells unharmed. The experiments done in the lab and in mice have shown promising results, where the cancer cells die off after the light treatment.
Study: Addition of Short-term ADT Fails to Improve Survival over Radiotherapy Alone for Intermediate-Risk PCa 
Biotech companies are racing to create Killer T Cells that target all cancer, PCa included, by the end of 2017, insuring them untold wealth:
Some Difficulties Translating Scientific Studies into News We Can Use
Dendritic Cell Therapy 
