Breast Cancer Resources

Breast cancer is the second leading cause of cancer death in women, after lung cancer, according to the American Cancer Society. About 212,920 women in the United States will be found to have invasive breast cancer in 2006. About 40,970 women will die from the disease this year.

What is breast cancer?

Cells in the body normally divide only when new cells are needed. Sometimes, cells in a part of the body grow and divide out of control, which creates a mass of tissue called a tumor. If the cells that are growing out of control are normal cells, the tumor is called benign (not cancerous.) If however, the cells that are growing out of control are abnormal and don't function like the body's normal cells, the tumor is cancerous.

How many people have breast cancer?

Right now, according to the American Cancer Society, there are slightly over 2 million women living in the United States who have been treated for breast cancer.

What causes breast cancer?

It isn't know what causes breast cancer, although there are certain risk factors that may put you at higher risk of developing it, according to WebMD. A person's age, genetic factors, personal health history and diet all contribute to breast cancer risk.

What are the types of breast cancer?

The most common types of breast cancer, according to WebMD, are:

Invasive ductal carcinoma. This cancer starts in the milk ducts of the breast. Then it breaks through the wall of the duct and invades the fatty tissue of the breast. This accounts for 80% of invasive cases.

Ductal carcinoma in situ is ductal carcinoma in its earliest stage (stage 0). The disease is confined to the milk ducts and has not invaded nearby breast tissue. It is almost always curable.

Infiltrating lobular carcinoma. This cancer has spread to surrounding tissues or the rest of the body. It accounts for about 10 percent of invasive breast cancers.

Lobular carcinoma is cancer that is only in the lobules of the breast. It serves as a marker for the increased risk of developing breast cancer later, possibly in both breasts.

Who gets breast cancer?

Breast cancer is the most common cancer among American women, after nonmelanoma skin cancer. Approximately 1 in almost every 8 women will develop breast cancer in her lifetime, according to WebMD. Only 5-10 percent of breast cancers occur in women with a clearly defined genetic predisposition for the disease. The majority of breast cancer cases are "sporadic," meaning there is no direct family history of the disease. The risk for developing breast cancer increases as a woman ages.

What are the warning signs?

Due to the increased use of mammography, most women are diagnosed at very early stages of breast cancer before symptoms appear. However, not every breast cancer is detected through mammography. The Susan G. Komen Cancer Foundation has warning signs.

To learn more about breast cancer:

• Click here for a breast cancer guide from WebMD.

• The American Cancer Society has resources on breast cancer.

• The BreastCancer.org has additional resources.

• Click here for resources from the Susan G. Komen Breast Cancer Foundation.

• Learn about the most common cancers, who gets them and how they are treated through a CBSNews.com interactive.