After skin cancer, breast cancer is the second most common malignancy among women. Breast cancer is one kind of cancer that starts in the breast. Either the left or right breast might be where it starts. Breast cancer may affect men and women equally, although women are far more likely to get it. Breast cancer is a disorder when the cells in the breast grow uncontrollably. There are several types of breast cancer. The kind of breast cancer is determined by which breast cells become malignant. When cells in your breast proliferate and enlarge out of control, a lump of tissue known as a tumor results. This is how breast cancer arises. Feeling a lump, seeing a change in breast size, or observing changes to the skin surrounding your breasts are all possible breast cancer signs.