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.

Inclusion Criteria:

• females aged 20-90 who are having surgery to confirm epithelial ovarian cancer.

Exclusion Criteria:

• patients who have a diagnosis of non-epithelial histology.

Patients with histologically confirmed epithelial ovarian cancer (EOC) who have had surgical resection for their disease will be included in this study.