T-lymphocytes contain a protein called PD-1 on their cell membrane. Some cancer cells carry a receptor molecule on their cell membrane that attaches to PD-1 and switches off the T-lymphocyte. A monoclonal antibody, lambrolizumab, has been developed against this receptor. Trials found that, among 54 of 135 people with advanced skin cancer who were treated with lambrolizumab, the tumours shrank to less than half their original volume. In 6 of the 57 people who received the highest dose, the tumours vanished. Which conclusion can be made correctly from this information?
- A1, 2, 3 and 4
- B1, 2 and 4 only
- C1 and 3 only
- D2, 3 and 4 only