The content of water in cancerous and normal human prostate in vitro tissues was shown to be different using near infrared (NIR) spectroscopy. The water absorption peaks at 1444 nm and 1944 nm are observed in both types of prostate tissues. The measurements show that less water is contained in cancerous tissues than in normal tissues. The OH stretching vibrational overtone mode at 1444 nm and other water overtone modes provide key spectroscopic fingerprints to detect cancer in prostate tissue. Transmission and backscattered spectral imaging were measured in cancer and normal prostate tissues. The degree of polarization for 700 nm, 800 nm, 1200 nm, and 1450 nm is larger for normal than for cancer tissues. The knowledge about water content offers a potential as a diagnostic tool to better determine and image cancer in prostate and in other tissues types such as breast and cervix using the absorption from vibrational overtones of H(2)O molecules in the NIR.