DOG1: Definition


Print this article

DOG1 (Discovered On GIST-1) is a protein found on the surface of certain cells. Pathologists use it as a diagnostic marker, a protein they can stain for to help identify what type of tumor they are looking at. DOG1 was first discovered in gastrointestinal stromal tumors (GISTs), which is where its name comes from, but it is also present in some normal tissues and in several other tumors. DOG1 is used to help make a diagnosis; it is not a test that decides which treatment a patient receives. This article explains what DOG1 is, how it is tested, and what a positive or negative result can mean on a pathology report.

What does DOG1 do, and which normal cells make it?

DOG1 is a channel that lets chloride, a type of electrically charged particle (ion), pass in and out of the cell. Controlling the movement of ions like this is part of how cells carry out their normal activities. The gene that carries the instructions for making DOG1 is called ANO1. In the body, DOG1 is normally made by the interstitial cells of Cajal, specialized cells in the wall of the digestive tract that help coordinate the muscle contractions that move food through the gut. DOG1 is also found in some normal cells of the salivary glands and kidneys. Because DOG1 is present in these specific cell types, it is useful for identifying tumors that arise from them.

How do pathologists test for DOG1?

Pathologists test for DOG1 using immunohistochemistry, a laboratory test that uses special antibodies to detect a specific protein in a tissue sample. The antibody attaches to DOG1 if it is present, producing a color change that a pathologist can see under the microscope. The result is reported as positive or negative:

  • DOG1-positive — The tumor cells contain the DOG1 protein. In the right context, this supports certain diagnoses, most importantly GIST. DOG1 is especially valuable because it is often positive in GISTs that are negative for CD117 (KIT), the other main marker used to identify GIST. For this reason, DOG1 and CD117 are frequently tested together.
  • DOG1-negative — The DOG1 protein was not detected in the tumor cells. On its own, a negative result does not rule out any specific diagnosis. The pathologist interprets it together with the appearance of the tumor and the results of other stains.

Because DOG1 can be present in more than one type of tumor, its result is always interpreted alongside the microscopic appearance of the tumor and other markers, rather than on its own.

Which tumors can be positive for DOG1?

DOG1 can be positive in both noncancerous (benign) and cancerous (malignant) tumors. Testing for DOG1 can help tell these apart from other tumors that look similar under the microscope.

Noncancerous tumors that can express DOG1 include breast fibroadenoma (a common benign breast tumor), chondroblastoma (a rare benign bone tumor), cylindroma (a benign skin tumor of the scalp or face), hidradenoma papilliferum and hidrocystadenoma (benign sweat gland tumors), mixed tumor of the skin, pilomatrixoma (a benign tumor of hair follicle cells), renal oncocytoma (a benign kidney tumor), and steatocystoma (a benign tumor of oil-producing glands).

Cancerous tumors that can express DOG1 include:

DOG1 is especially helpful for diagnosing GIST, but it also provides useful information for these other tumor types. In every case, the pathologist combines the DOG1 result with the tumor’s appearance and other test results to reach the final diagnosis.

Questions to ask your doctor

  • Why was DOG1 testing done on my sample?
  • Was the DOG1 result positive or negative?
  • What diagnosis do the DOG1 and other stain results support?
  • Was CD117 (KIT) also tested, and what did it show?
  • Does my result point to a GIST, or to a different type of tumor?
  • Is any additional testing needed to confirm the diagnosis?
  • What are the next steps based on these results?

Related articles on MyPathologyReport.com

A+ A A-
Was this article helpful?