Final answer:
Herceptin and Lapatinib target the HER2 receptor in breast cancer treatment. Herceptin enlists immune support to remove HER2, while Lapatinib inhibits HER2's autophosphorylation, impairing its signaling and reducing cell division.
Step-by-step explanation:
The student is asking about the role of Herceptin (trastuzumab) and Lapatinib in the treatment of human breast cancer in relation to the HER2 receptor. Herceptin is a monoclonal antibody that targets the HER2 receptor, which is overexpressed in a significant percentage of breast cancer cases, leading to uncontrolled cell growth. Its role is to mark HER2 for removal by the immune system, and this, combined with chemotherapy, can improve survival rates in metastatic breast cancer patients. Lapatinib is a small molecule inhibitor that blocks the autophosphorylation of HER2 receptor tyrosine kinase, interfering with its signaling pathway and thereby reducing tumor cell proliferation.