11.   Doctors say that over time, cancer cells can become resistant to hormone treatments.

12.   Even if cells are found to be atypical, it does not mean cancer is present, because not all atypical cells become cancerous.

13.   Further, the cell replication occurring in the breasts does not complete its full course and the cells may become cancerous.

14.   Guarente and his colleagues showed that when the yeast helicase gene is disrupted, the yeast cells become more sensitive to the waste circles and age prematurely.

15.   He said he worried about long-term effects, noting that normal cells become cancerous in a manner similar to the way these cells were grown in the laboratory.

16.   Heart cells do not become liver cells, lung cells do not become brain cells.

17.   His discoveries in genetic research helped establish the experimental framework for determining how undeveloped, embryonic cells become specialized cell types.

18.   His cell has become a temple, complete with a brass statuette of the Buddha and, when the warden allows, burning candles and incense.

19.   How does a single fertilized cell become an organism of trillions of specialized cells?

20.   If the human mitochondria survived, the hybrid cow-human cell should become fully human as the cow proteins were replaced by natural turnover.