We present the preliminary results of quantitative characterization of normal and malignant breast tissues in a human subject. The tissue was probed non-invasively by multi-wavelength (674, 786, 803, 849, and 956 nm) multifrequency (50MHz-1GHz) diffuse photon density waves (DPDW). The optical characterization of the lesion was co-registered with Ultrasound. Ultrasound images provide us information about the lesion size and position which were used for optical characterization of localized inhomogeneity (lesion). Multifrequency allows us to extract the optical properties (the absorption and reduced scattering coefficients) at a single source-detector separation. We assign the optical properties of the lesion by fitting the data to analytic solutions of diffuse photon density waves for a semi-infinite heterogeneous medium. We find that the lesion and normal tissues are clearly resolvable. We also find that the optical contrast is elevated by analyzing the data with the sophisticated heterogenous model (as opposed to a homogeneous model). Multi-wavelength spectroscopic measurements indicate that the lesion might have higher water concentration.