Until recently people believed pancreatic ductal adenocarcinoma (PDAC), the most common and lethal pancreatic cancer, to be a single cancer type. In the last few years, subtypes of PDAC have been discovered, providing potential for treating each subtype as a different disease. This is important in PDAC as most patients don’t respond to current treatments.

Unfortunately, the PDAC subtyping methods were not useful in the clinic as they have been developed in a group dependent manner, where subtype is determined based on groups of samples. The addition or removal of a single sample to the overall group could change any other sample’s subtype.

One study set about to change that and develop a method to subtype a single patient. The researchers first determined they would try to create a single sample method to break patients into classical or basal-like subtypes, because classical patients respond better to therapy. Therefore, if doctors could tell if a patient was classical or basal-like, they could choose different treatment option.

Researchers created a system of gene pairs, where one first gene is present in classical patients, and the second gene is present in basal-like patients. Think of these pairs as light switches. Depending on which way the light switch points, a sample can be classified as one subtype or the other. With just 16 genes, they method is inexpensive and easily applied in a clinical setting.

Overall, researchers managed to create a clinically actionable subtyping system which has recently been adopted into the PanCAN Know Your Tumor Program and the Precision Promise clinical trial. The hope is that trials will be able to identify which patients will respond to their therapies as well as to create subtype specific therapies, similar to breast cancer where treatment is specialized by subtype.