OUTLINE: Exhaled breath samples are collected from patients and healthy volunteers. The samples are analyzed by gas chromatography Fourier transform ion cyclotron resonance mass spectrometry (GC/FT-ICR MS) to determine chemical compositions, identities, and predictive patterns of biomarkers in exhaled breath condensate. GC/FT-ICR MS and trained canine olfaction are used to distinguish between exhaled breath samples from patients with ovarian epithelial cancer, patients with polycystic ovarian syndrome or endometriosis, and healthy volunteers.