A glass of water and a glass of jelly look the same but behave differently. So it is with prostate tissue: on a standard slide under a microscope, you can see both the tumor glands and the supporting connective tissue around them. Previously, pathologists focused only on the glands, treating the support as mere background.
PROTAS was trained on thousands of images and found important changes in this "background." Around aggressive tumors, the connective tissue becomes denser, its fibers tangle, and cells enlarge. It's like a construction site surrounded by fences and access roads — the tumor reshapes its environment to suit its needs.
The main benefit is prediction. If a biopsy slide taken before surgery shows that the connective tissue has already been remodeled, the risk of recurrence is higher. PROTAS calculates this risk as well as, and sometimes better than, current clinical indicators. Thus, an ordinary glass slide becomes a map of the disease's future.
Reactive stroma is not a passive scaffold but an active participant: its cells can contract and pull on the tumor, helping it invade neighboring tissues.