Women who have a high level of insulin have a higher risk of developing breast cancer than women who have a lower level of the hormone.

A study published in Cancer Research, a journal of the American Association for Cancer Research, suggests a possible role for nicotine in breast tumor development and metastases.

A new study from the American Cancer Society finds that while breast cancer death rates are decreasing for white women in every U.S. state, for African American women, death rates are either flat or rising in at least half the states.

Physicians who treat women with the breast cancer susceptibility gene BRCA1 often remove their patients’ ovaries to eliminate the source of estrogen they believe fuels cancer growth. Yet they also know that anti-estrogen therapies don't work to treat breast or ovarian cancer that might develop.

Estrogen, which binds estrogen receptor alpha (ER-alpha), is a risk factor for breast cancer development. However, one-third of new breast cancers lack detectable ER-alpha. These ER-alpha–negative cancers are more aggressive and have a worse prognosis than do ER-alpha–positive breast cancers, and have been thought to be estrogen independent.

The chances of developing breast cancer are to some extent inherited, but important new findings suggest survival also runs in the family. Research published in the online journal Breast Cancer Research suggests that if a woman succumbs to breast cancer her daughters or sisters are over 60 percent more likely to die within five years if they develop the disease.

Women who consume higher amounts of calcium and vitamin D may have a lower risk of developing premenopausal breast cancer, according to a report in the May 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.