ACADEMY PUBLIC POLICIES

Every person’s fingerprint is unique. And so is every person’s cancer fingerprint. This “cancer fingerprint” or “cancer signature” consists of all the genes a cancer is using and can be viewed as a computerized readout.

D., a forty-five-year-old teacher, feels a lump in her breast. She has surgery to remove the mass, and the pathology shows a lymphoma. D. is surprised and asks, “Do I have breast cancer?” The answer is no, she has lymphoma of the breast, not breast cancer.

Every organ in the human body is made up of a mixture of cells that cooperate to support the functions of that organ. For example, the heart contains cardiac muscle cells that enable it to pump and nerve cells that transmit electrical signals that spark the muscle to pump in a rhythmic fashion. Another example is the breast or mammary gland, whose main function is the production of milk to sustain the newborn. Breast milk is produced by the glandular portions of the breast, composed of glandular (or gland) cells.

Thus far, we have been considering carcinomas as cancers that pose a threat to life because they are “invasive,” which means that they have the potential to metastasize to other parts of the body. A pathologist will usually include the term “invasive” or “infiltrating” in a pathology report to indicate this important aspect of the cancer. For example, a tumor of the larynx may show “invasive squamous cell carcinoma,” one from the stomach, “invasive adenocarcinoma,” or one from the breast, “infiltrating ductal carcinoma.”