(a) A female patient initially presented with amenorrhea-galactorrhea syndrome because of a brain tumor that secreted an excessive amount of hormone. What is this hormone, and how does it cause amenorrhea and galactorrhea? (4 marks) 

(b) Identify ONE drug that can reduce this hormone and explain its pharmacological action. (2 marks) 

(c) After three years of therapy with no significant tumor shrinkage, she developed Cushing's syndrome. Name ONE drug that can be used to treat Cushing's syndrome and explain how it works. (3 marks) 

(d) This patient was diagnosed with metastatic bladder cancer when she was old. Her cancer was treated with a combination therapy that included methotrexate, vinblastine, doxorubicin, and cisplatin. Explain the mechanisms by which they can kill cancer cells and list any side effects. (8 marks) 

(e) Durvalumab, a monoclonal antibody, was recently approved to treat bladder cancer. What is its mechanism of action? (3 marks)