Breast Cancer
Posted: Thu Oct 15, 2026 6:47 am
Breast cancer happens when breast cells mutate and become abnormal cells that multiply and form tumors. It typically affects women over 50, but it can also affect men and younger women. Symptoms vary but may include a lump, thickening skin or nipple discharge. Healthcare providers treat breast cancer with surgery, radiation and drug therapies
Cancer?
What Is Breast Cancer?
Cancerous tumor inside the breast
Breast cancer tumors develop when breast cells mutate and grow.
Breast cancer happens when healthy breast cells become abnormal, multiply and form tumors. Most breast cancers are carcinomas that start in milk ducts or milk-producing glands. Most cases are invasive. This means that without treatment, a tumor can spread to other parts of your body.
Breast cancer is one of the most common cancers that affects women. Approximately 1 in 8 women in the United States will develop breast cancer in their lifetime. Although it’s rare, male breast cancers also occur.
Most people who have breast cancer survive it. Still, what a breast cancer diagnosis means is different for everyone. The cancer type, its stage and your response to treatment are just a few factors that will shape your outlook.
Breast cancer types
There are several types of breast cancer. Knowing the type helps your healthcare provider choose the best treatment. Common types include:
Invasive ductal carcinoma (IDC): This cancer starts in your milk ducts and spreads to nearby breast tissue. It’s the most common type of breast cancer in the U.S.
Invasive lobular carcinoma (ILC): This cancer starts in the milk-producing glands (lobules) in your breast and often spreads to nearby breast tissue. It’s the second most common type of breast cancer in the U.S.
Ductal carcinoma in situ (DCIS): Like IDC, this breast cancer starts in your milk ducts. The difference is that DCIS doesn’t spread beyond them.
Less common breast cancer types include:
Inflammatory breast cancer (IBC): This fast-growing cancer looks like a rash on your breast.
Paget’s disease of the breast: This cancer affects the skin of your nipple and may look like a rash.
Molecular receptor subtypes
During diagnosis, healthcare providers look for receptors on cancer cells to classify them into subtypes. Receptors are protein molecules. Cells with receptors (+) can attach to hormones, like estrogen and progesterone. This makes the cancer grow. High amounts of HER2 protein on cancer cells can also lead to cancer growth.
Cancer?
What Is Breast Cancer?
Cancerous tumor inside the breast
Breast cancer tumors develop when breast cells mutate and grow.
Breast cancer happens when healthy breast cells become abnormal, multiply and form tumors. Most breast cancers are carcinomas that start in milk ducts or milk-producing glands. Most cases are invasive. This means that without treatment, a tumor can spread to other parts of your body.
Breast cancer is one of the most common cancers that affects women. Approximately 1 in 8 women in the United States will develop breast cancer in their lifetime. Although it’s rare, male breast cancers also occur.
Most people who have breast cancer survive it. Still, what a breast cancer diagnosis means is different for everyone. The cancer type, its stage and your response to treatment are just a few factors that will shape your outlook.
Breast cancer types
There are several types of breast cancer. Knowing the type helps your healthcare provider choose the best treatment. Common types include:
Invasive ductal carcinoma (IDC): This cancer starts in your milk ducts and spreads to nearby breast tissue. It’s the most common type of breast cancer in the U.S.
Invasive lobular carcinoma (ILC): This cancer starts in the milk-producing glands (lobules) in your breast and often spreads to nearby breast tissue. It’s the second most common type of breast cancer in the U.S.
Ductal carcinoma in situ (DCIS): Like IDC, this breast cancer starts in your milk ducts. The difference is that DCIS doesn’t spread beyond them.
Less common breast cancer types include:
Inflammatory breast cancer (IBC): This fast-growing cancer looks like a rash on your breast.
Paget’s disease of the breast: This cancer affects the skin of your nipple and may look like a rash.
Molecular receptor subtypes
During diagnosis, healthcare providers look for receptors on cancer cells to classify them into subtypes. Receptors are protein molecules. Cells with receptors (+) can attach to hormones, like estrogen and progesterone. This makes the cancer grow. High amounts of HER2 protein on cancer cells can also lead to cancer growth.