1.   In other mice in which colonies of normal human cells were grafted, the virus had little or no effect.

2.   Systemic treatment of cancer is bedevilled by the similarity of tumour cells to normal cells, at least under most physiological conditions.

3.   The children now have normal immune cell counts and live at home, without treatment.

4.   The idea is to cause progressive damage to the cancer cells, while allowing the normal cells to recuperate.

5.   The protein eats normal cells, leading to the drastic weight loss which weakens patients and prevents them fighting the disease.

6.   If normal cells can be stimulated to divide, then abnormal ones could also be prompted to multiply, so causing or accelerating skin cancer.

7.   It is a medical problem to attack the virus without attacking the normal cells.

8.   Although a number of studies have described the HPV transforming activity in the transformation of normal cells, the carcinogenic mechanisms of HPV is not yet completely understood.