PGR and breast cancer: In breast cancer, the inhibitory response to kaempferol is dependent on the typology of the cancer cells examined because the presence or absence of the characteristic receptors that are used for their classification (estrogen receptor, progesterone receptor, human EGFR2) can influence not only the concentration but also the cell mechanism used to respond to the stimulus, and moreover, breast cancer cells have other mutations in essential genes that can alter the response, justifying the different results reported in literature.