Molecular Pathology of Gastrointestinal Tumors

Molecular pathology is a modern branch of pathology that investigates genetic and molecular changes in tumors. While traditional pathology primarily assesses the appearance of tumor tissue under a microscope, molecular pathology additionally analyzes changes in the DNA, RNA, or specific proteins of cancer cells. This allows tumors to be characterized more accurately and treated in a more targeted manner.

Molecular diagnostics is playing an increasingly important role, particularly in the diagnosis of tumors of the gastrointestinal tract—such as colorectal cancer, stomach cancer, pancreatic cancer, or bile duct cancer.

Key applications:

Selection of targeted therapies:

• Certain genetic alterations determine whether targeted therapy or immunotherapy will be effective. Molecular pathology provides the key information needed for this.

Prognosis and treatment planning:

• Some molecular markers provide clues as to how aggressive a tumor is and how well it responds to certain treatments.

Within the GIOS network, more than 600 gastrointestinal tumors have already undergone molecular testing (as of February 2026). This has yielded important insights for treatment. The tests are coordinated by molecular oncologists and are periodically reviewed at molecular tumor boards.