31.   The researchers said that when they placed ICZ in a tissue culture of breast cancer cells, proliferation was inhibited.

32.   The scientists analyzed DNA taken from women with normal breast cells, women with early breast cancer and women with advanced, metastatic disease.

33.   When the breast cancer cells receive, or hear, too many growth signals --thanks to the extra proteins -- they divide and spread quickly.

34.   Estrogen, the female hormone, encourages the growth of some breast cancer cells.

35.   That study found that the reaction of breast cells to tamoxifen changes over time until the drug starts to behave like the hormone it is supposed to block.

36.   The chemokines then attract breast cancer cells circulating in the body.

37.   The researchers worked with human breast cells.

38.   The strategy was tested in mice that had received transplants of tumors grown from breast cancer cells.

39.   In pregnancy, however, breast cells mature very quickly during the third trimester, and this makes them less sensitive to carcinogenic triggers.

40.   Previous studies have indicated that immature breast cells are relatively easily infiltrated by carcinogens, sometimes causing a tumour to develop several years later.