What Is Cancer?

Cancer refers to any one of a large number of diseases characterized by the development of abnormal cells that divide uncontrollably and have the ability to infiltrate and destroy normal body tissue. Cancer can spread throughout your body.

Cancer refers to any malignant tumor. There are many types of cancers which can occur in nearly every organ. The pattern of growth of cancer cells often resembles a twisted and distorted version of the tissue that is arising. Before we proceed, there are a few basic terms which must be defined.

A tumor means a swelling or mass. A tumor can be benign or malignant.

Benign to a tumor which does not have the potential to spread beyond the organ it arises.

Malignant refers to a tumor which has the ability to spread or metastasize beyond the organ from which it arises.

Broadly speaking, cancers can be divided into four major categories:

1. A carcinoma is a cancer which is derived from the lining cells, or epithelium, of an organ. There are 4 major types of epithelium in the body (Glandular, squamous, transitional, and pseudostratified). Some types are only found in a few select organs such as the lung (pseudostratified) or urinary bladder (transitional). Carcinomas can arise from any of these epithelial types. For example, breast carcinoma is most commonly derived from the lining cells of the milk producing glands. A carcinoma with a glandular growth pattern is an adenocarcinoma. Common adenocarcinomas include prostate, colon, and breast. A carcinoma with a growth pattern resembling the squamous lining cells is termed a squamous cell carcinoma. Common squamous cell carcinomas are found in the esophagus and skin. However, any of these organs may have either type of carcinoma arising from it, although these latter diagnoses are exceedingly rare.
2. A sarcoma a cancer derived from the soft tissues of the body. Soft tissues include the fat, muscle, nerves, and connective tissue support. Although not usually soft, it also includes bone and cartilage.
3. A lymphoma a cancer derived from the white blood cells that are present in the lymphoid tissues of the body. These sites most commonly include the lymph nodes and spleen. However, lymhomas may arise from any organ and body site.
4. A melanoma a cancer derived from melanocytes. These are the pigment producing cells present in the skin. A mole is a benign growth of melanocytes.

Being diagnosed with cancer can be frightening. But understanding what's going on inside your body can help you feel more in control of your disease.