When a mass(MAS) — An abnormal growth or tissue or tumor(TOO-MER) — Abnormal growth in the body is discovered, doctors will take a sample(SAM-PULL) — The tissue obtained from a biopsy or surgery of tissue(TISH-YOU) — The accumulation of cells that make up parts of the body, like organs (during a biopsy(BYE-OP-SEE) — Removal of a sample or piece of tissue to identify abnormalities) to determine what it is.

But have you wondered where a biopsied tissue sample goes?

The tissue sample collected during a biopsy goes to a pathologist(PATH-ALL-O-JIST) — A doctor who specializes in looking at tissue samples to identify diseases such as cancer. So—what is a pathologist? Well, pathology is the study of human tissue, so a pathologist is a type of doctor who analyzes tissue samples.

To make this easier to understand, we can compare a pathologist to a gardener.

If the gardener thinks that a growth might be a weed, he or she will remove a small piece of it to analyze. Looking closer at the sample allows the gardener to decide if the plant is truly a weed. Additionally, the gardener can determine if it is a dandelion, clover, or something else.

Similarly, pathologists can look very closely at the biopsied tissue. First, the pathologist will determine if the tissue is benign(BE-NINE) — A growth in the body that is neither invasive nor cancerous and has a very low risk of spreading, premalignant(PRE-MA-LIG-NENT) — A growth that will worsen and grow into a cancer, becoming malignant if not removed, or malignant(MA-LIG-NENT) — A cancer or abnormal tumor that grows uncontrollably and may spread to other parts of the body. If the tissue is malignant (cancerous), then the pathologist will try to confirm where the tissue originated from (which will tell him or her what type of cancer it is).

While sometimes it's pretty easy to determine what type of cancer a tissue sample is, other times, it's more difficult. Cancer can arise from any organ or tissue in the body, and a lot of cancers have similar characteristics.

Fortunately, just like each type of weed can be classified by certain characteristics, so can cancers.

Pathologists can look for special characteristics in the sample to help them identify the organ the cancer started in. And, to do this, pathologists need special tools. Their tools are called stains.

But a pathologist doesn't just use the stains to determine the type of cancer. He or she digs deeper to learn more about the cancer.

Applying more specific stains to the tissue can reveal different proteins in the cell(SEL) — One of the most basic components of all living things that together form the entire body and contains many smaller parts that guide its function. Each type of cancer has its own unique combination of proteins and receptors(REE-SEP-TORS) — A protein in or on a cell that may control some functions of the cell.

Testing for these proteins is extremely important because the proteins will tell the doctor which treatments he or she could use. When oncologists know which type of receptor to target, they can recommend a treatment(TREET-MINT) — Techniques to help eliminate or control a disease that might have more success in eliminating or treating that type of cancer.