Biometric Research Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.|Biometric Research Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.|Biometric Research Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.|Biometric Research Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.|Biometric Research Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.