Which of the following is a targeted therapy for ER+ breast cancer?

The targeted therapy for ER+ (Estrogen Receptor Positive) breast cancer is a critical area of focus in oncology, as it directly addresses the unique biology of tumors that depend on estrogen for growth. The correct option in this context is Palbociclib (Ibrance).

Palbociclib is a CDK4/6 inhibitor that works by blocking specific proteins in cancer cells that are involved in cell division. By inhibiting these proteins, Palbociclib effectively slows down or stops the growth of ER+ breast cancer cells, making it particularly beneficial in treating this type of cancer, especially in combination with endocrine therapies such as aromatase inhibitors or selective estrogen receptor modulators.

Other options, while relevant in the context of breast cancer therapies, do not specifically target the hormonal pathways associated with ER+ breast cancer in the same way. For example, Trastuzumab is designed for HER2-positive breast cancer and does not target estrogen receptors. Raloxifene is a selective estrogen receptor modulator used primarily for osteoporosis prevention and not as a treatment for ER+ breast cancer. Aromatase inhibitors, while effective in treating ER+ breast cancer, are not considered targeted therapies in the same manner as CDK4