The fat correction method enables robust APT-CEST quantification in the human breast and proved its suitability for examinations in vivo. We present to the extent of our knowledge the first APT-CEST contrast corrected for fat signal contribution, spillover, B1 field inhomogeneities and T1 relaxation in a breast cancer patient. The CEST contrast increased threefold compared to the measurement of a healthy volunteer. Repeated CEST imaging over the course of one menstrual cycle in one healthy woman did not reveal a hormonal correlation of APT contrast. A clinical study in healthy premenopausal volunteers will now investigate the dependency on menstrual cycle.