21.   It calls into question the assumption that early identification of breast tumors, before they can be felt in an external examination, improves the chances of a cure.

22.   It works by blocking the effects of estrogen, which can spur the growth of some breast tumors.

23.   Osborne noted that other genes are known to play a role in a smaller percentage of breast tumors.

24.   One was that the hormones used in birth control pills, estrogen and progestin, might accelerate the growth of breast tumors that are already present.

25.   Other studies had shown that it can inhibit growth of breast tumors that respond to natural estrogens.

26.   Previous discoveries of genes that cluster in cancerous breast tumors have lead to clinical trials for new therapies.

27.   Scientists have discovered a new gene that probably influences the growth and progress of breast cancer tumors.

28.   She sued him for malpractice when another doctor found a breast tumor the following year, and the case was settled out of court recently.

29.   Since most breast tumors are benign, doctors can easily mistake a malignant tumor for a benign cyst, especially in young women.

30.   Since natural estrogens are known to promote the growth of breast tumors, anything that interferes with their activity should lower the risk of breast cancer.