Breast and prostate cancers are usually dependent on hormones (oestrogen and testosterone, respectively) for their growth. But, these hormones have another role, in switching off the body’s immune system – so that it doesn’t attack these tissues.
Switching off the immune system from attacking oestrogenised-tissues, such as the womb, is crucial to keeping developing babies protected from their mother’s immune system – which otherwise would be at risk of damaging babies before their birth.
Recently, new ways of bypassing the switch-off of immune systems against breast and prostate cancers have been found. For breast cancers, inhibiting a key protein called TGFbeta receptor helps change the cancer so CAR-T cells can attack it.
For prostate cancers, using different white blood T cells called gamma-delta T cells, in conjunction with a bone-protecting drug called zoledronic acid, seems to help improve the ability of CAR-T cells to attack the cancer.