ESR1 and breast cancer: This design has two purposes: first of all, the porphyrin group can be used as a photosensitizer in order to carry on photodynamic therapy (PDT); secondly, the amino groups provide positive charges which can interact with a siRNA that can be used for FOXA1 knockdown (FOXA1 KD) in estrogen receptor positive breast cancer cells (ER + BC cells) (178, 179).