NIH - Medical Encyclopedia Breast cancer "There are several different types of breast cancer. Ductal carcinoma begins in the cells lining the ducts that bring milk to the nipple and accounts for more than 75% of breast cancers. Lobular carcinoma begins in the milk-secreting glands of the breast but is otherwise fairly similar in its behavior to ductal carcinoma. Other varieties of breast cancer can arise from the skin, fat, connective tissues, and other cells present in the breast. … Some women have what is known as HER2-positive breast cancer. HER2, short for human epidermal growth factor receptor-2, is a gene that helps control cell growth, division, and repair. When cells have too many copies of this gene, cell growth speeds up. It’s believed that HER2 plays a key role in turning healthy cells into cancerous ones. Some women with breast cancer have too much HER2, and are therefore considered HER2-positive. … Some families appear to have a genetic tendency for breast cancer. Two variant genes have been found that appear to account for this: BRCA1 and BRCA2. … The body's reduced ability to get rid of abnormal cells leads to damage that gradually accumulates. Women carrying mutated BRCA1 and/or BRCA2 genes start with pre-existing dysfunction of this system and have a "head start" in this damaging process. Hormones are important because they encourage cell growth. High levels of hormones during a woman's reproductive years, especially when they are not interrupted by the hormonal changes of pregnancy, appear to increase the chances that genetically damaged cells will grow and cause cancer."

Types of breast cancer "Common types of breast cancer The most common types of breast cancer begin either in your breast's milk ducts (ductal carcinoma) or in the milk-producing glands (lobular carcinoma). The point of origin is determined by the appearance of the cancer cells under a microscope. In situ breast cancer In situ (noninvasive) breast cancer refers to cancer in which the cells have remained within their place of origin — they haven't spread to breast tissue around the duct or lobule. The most common type of noninvasive breast cancer is ductal carcinoma in situ (DCIS), which is confined to the lining of the milk ducts. The abnormal cells haven't spread through the duct walls into surrounding breast tissue. With appropriate treatment, DCIS has an excellent prognosis. Invasive breast cancer Invasive (infiltrating) breast cancers spread outside the membrane that lines a duct or lobule, invading the surrounding tissues. The cancer cells can then travel to other parts of your body, such as the lymph nodes. Invasive ductal carcinoma (IDC). IDC accounts for about 70 percent of all breast cancers. The cancer cells form in the lining of your milk duct, then break through the ductal wall and invade nearby breast tissue. The cancer cells may remain localized — staying near the site of origin — or spread (metastasize) throughout your body, carried by your bloodstream or lymphatic system. Invasive lobular carcinoma (ILC). Although less common than IDC, this type of breast cancer invades in a similar way, starting in the milk-producing lobules and then breaking into the surrounding breast tissue. ILC can also spread to more distant parts of your body. With this type of cancer, you typically won't feel a distinct, firm lump but rather a fullness or area of thickening."

Breast lumps: Types of lumps and what they mean "Causes Breast lump causes: Breast cancer Breast cyst Fibroadenoma Fibrocystic changes Hamartoma Injury or trauma to the breast Intraductal papilloma Lipoma Mastitis Milk cyst (galactocele) Phyllodes tumor. "

NIH – Breast Cancer “Breast cancer affects one in eight women during their lives. Breast cancer kills more women in the United States than any cancer except lung cancer. No one knows why some women get breast cancer, but there are a number of risk factors. Risks that you cannot change include • Age - the chance of getting breast cancer rises as a woman gets older • Genes - there are two genes, BRCA1 and BRCA2, that greatly increase the risk. Women who have family members with breast or ovarian cancer may wish to be tested. • Personal factors - beginning periods before age 12 or going through menopause after age 55 Other risks include being overweight, using hormone replacement therapy, taking birth control pills, drinking alcohol, not having children or having your first child after age 35 or having dense breasts. Symptoms of breast cancer may include a lump in the breast, a change in size or shape of the breast or discharge from a nipple. Breast self-exam and mammography can help find breast cancer early when it is most treatable. Treatment may consist of radiation, lumpectomy, mastectomy, chemotherapy and hormone therapy. “

NHS – Breast Cancer “Types of breast cancer: There are several different types of breast cancer, which can develop in different parts of the breast. The most common is known as ductal breast cancer, which develops in the cells that line the breast ducts. Ductal breast cancer accounts for about 80% of all cases of breast cancer. Other, less common types of breast cancer include lobular breast cancer, which develops in the cells that line the milk-producing lobules, inflammatory breast cancer, and Paget's disease of the breast. It is possible for breast cancer to spread to other parts of the body, such as the liver, bones, or lymph nodes (small glands that filter bacteria from the body). … Symptoms: The main symptom of breast cancer is usually a lump, or thickened area of tissue, in your breast. The majority of breast lumps are found by the women who have them, and it is very important that you are aware of any lumps, or changes in the appearance, feel, or shape of your breasts. This is important because the sooner a cancerous lump is detected, the better the chances are that it will be treated successfully. Changes to look out for You should see your GP if you notice any of the following: • a lump, or thickened area of tissue, in either breast, • discharge from either of your nipples (which may be streaked with blood), • a lump or swelling in either of your armpits,a change in the size, or shape, of one, or both, of your breasts, • dimpling on the skin of your breasts, • a rash on, or around, your nipple,a change in the appearance of your nipple, such as becoming sunken into your breast, or • pain in either of your breasts or armpits which is not related to your period. If you have a lump in your breast, it is important to remember that it may not be the result of breast cancer. In fact, 90% of breast lumps are benign (non-cancerous). For example, a breast lump may be caused by a harmless cyst (a small fluid-filled lump), or fibroadenoma (benign growths that are very common). You may also find that your breasts feel lumpy just before your period. However, if you notice any changes to one, or both, of your breasts, as listed above, you should always get it checked by your GP. “

NHS – Breast Cancer Expert (Video)

NHS – Breast Cancer Screening (Video)

Primary tumor location impacts breast cancer survival. (Am J Surg. 2008) “CONCLUSIONS: Upper-outer quadrant breast cancers have a more favorable survival advantage when compared with tumors in other locations. Factors that negatively impacted survival included high-grade tumors, advanced stage, and race.”

Adulthood Lifetime Physical Activity and Breast Cancer. (Epidemiology. 2008) “Women who increased their recreational activity in their 50s had significantly reduced risk, with those in the highest tertile of change being at a 27% lower risk. CONCLUSIONS:: Leisure-time moderate-to-vigorous activities reduce breast cancer risk irrespective of underlying host characteristics.”

Cruciferous vegetables, the GSTP1 Ile105Val genetic polymorphism, and breast cancer risk. (Am J Clin Nutr. 2008) “CONCLUSIONS: Cruciferous vegetable intake consistent with high isothiocyanate exposure may reduce breast cancer risk. Cruciferous vegetable intake also may ameliorate the effects of the GSTP1 genotype.”

Breast Cancer: Benign Breast Lumps (2007) “Eighty percent of all breast lumps are benign, which means they're not cancerous. Benign breast lumps usually have smooth edges and can be moved slightly when you push against them. They are often found in both breasts.

Mammographic Breast Density as a General Marker of Breast Cancer Risk (Cancer Epidemiology Biomarkers & Prevention 2007) "Overall mammographic density seems to represent a general marker of breast cancer risk that is not specific to breast side or location of the eventual cancer."

Lifetime physical activity and the risk of breast cancer: A case-control study. (Cancer Detect Prev. 2007) "Conclusions: These data are in concordance with the hypothesis that lifetime total physical activity is associated with decreased breast cancer risk. They also suggest that recreational physical activity at ages 14-20 years is the most beneficial. In addition, these findings confirm the majority of previous reports which implicated physical inactivity as important risk factor for breast cancer."

NCI - Breast Cancer

NCI – What You Need To Know About Breast Cancer

NCI - Characteristics of Breast Cancer Cases (graphic data)

NIH – Breast Cancer

NCI - Breast Cancer (PDQ®): Prevention