1.   And many tumor cells replicate very quickly and still are not sensitive.

2.   And they knew that many chemotherapy drugs, in addition to killing tumor cells, also fought angiogenesis.

3.   And with asbestos, research shows that, in some cases, just one fiber could get into one cell and cause it to become a tumor cell.

4.   Animal experiments showed the two-step gene transfer -- from herpes to retrovirus and from retrovirus to tumor cell -- could be accomplished.

5.   As a result, pregnant women are especially susceptible to bacteria, viruses and tumor cells during those weeks.

6.   At the moment, Weinberg is struggling with metastasis, where local tumor cells spread throughout the body, typically a death blow.

7.   Because blood vessel cells, unlike tumor cells, cannot develop resistance to drugs, they offer in principle a far better target for anti-cancer therapy.

8.   Because of these properties, Dietert said, purified mistletoe toxins show considerable promise as anti-cancer agents when delivered specifically to tumor cells.

9.   A key advantage of angiogenesis-blocking drugs is their much lower toxicity than conventional cancer drugs that attack tumor cells but also unavoidably kill normal cells.

10.   But he believes a new discovery about the genetics of tumor cells goes far toward explaining the apparently contradictory results.