Background: Tumor testing utility in Lynch syndrome (LS) diagnosis is established.
Aims: Analyze the differences between tumor testing efficiency in rectal (RC) and colon cancer (CC).
Methods: We performed immunohistochemistry (IHC) for MisMatch Repair (MMR) proteins (IHC-MMR) and MicroSatellite Instability analysis (MSI) on 482 unselected primary tumors: 320 CCs and 162 RCs.