11.   Estrogen is known to promote some breast tumors.

12.   Guise said it may eventually be possible to test breast tumors for excessive PTHrP to determine if it was more likely to spread to bone.

13.   He and his co-workers identified a protein that has become a key marker for an estrogen-dependent breast tumor.

14.   However, in most of the serious breast tumor cells they studied, the protein was present but in the wrong place.

15.   If successful, the technology would allow doctors to more easily locate malignant breast tumors, according to Dr. Mitchell Schnall, a radiologist at Penn.

16.   In fact, many doctors thought pregnancy was downright crazy because many breast tumors are driven by female hormones, which soar when a woman is pregnant.

17.   In its normal molecular form it acts to prevent the development of breast tumors.

18.   In some cases, scientists suspect soy may even contribute to the growth of cancerous breast tumors.

19.   Indeed, Folkman said in Amsterdam that some breast tumors secrete six different signals to build blood vessels.

20.   Intraoperative MRI guides the process, which is already being used to treat benign breast tumors and will soon be tried with malignant ones.