How Our Immune System Can Help Fight Cancer

There is growing evidence that our immune system can help fight cancer. This has stimulated
interest in the development and application of tumor vaccines for several human solid
tumors, including epithelial ovarian cancer (EOC). A major obstacle to the development of
these vaccines is that there are specialty cells called regulatory T cells that prevent the
immune system from attacking all of our organs. These regulatory T cells also prevent our
immune system for attacking cancer cells.

Indoleamine 2,3-dioxygenase (IDO), an enzyme that degrades an essential amino acid
tryptophan that is necessary for T cells to multiply, however regulatory T cells are less
susceptible to low levels of tryptophan, and can still multiply. This allows cancer growth
and progression. This may be explained by genetic polymorphisms (changes) in the IDO gene,
which may alter its function. Five of these changes in the IDO gene have been described. In
this research project, we are asking if you would donate a small piece of your tumor and
ascites to see if we can examine your IDO gene in the tumor cells and see if any of these
gene changes are present. We hope that this will help us understand how the immune system
works in EOC.

We hypothesize that genetic polymorphisms within the IDO gene alter its enzymatic activity
and affect the outcome of ovarian cancer patients. These findings have the potential to
translate into a method for predicting successful immunotherapy.