Background: Villin is a protein of the brush border of epithelial cells, which is used as an immunohistochemical marker for colorectal and gastrointestinal neoplasms. However, other tumor entities can also express villin.
Methods: To comprehensively determine villin expression, tissue microarrays containing 14,398 samples from 118 different tumor types as well as 608 samples of 76 different normal tissues were analyzed by immunohistochemistry.
Results: Villin was found in 54 of 118 tumor categories, including 36 tumor categories with strong staining. Villin expression was frequent in colorectal (60-100%), upper gastrointestinal tract (61-100%), pancreatobiliary (25-86%), and renal tumors (≤18%) as well as in mucinous ovarian cancers (67%), yolk sac tumors (76%) and in neuroendocrine neoplasms (22-41%). Reduced villin expression was linked to advanced pT stage, lymph vessel invasion, and microsatellite instability (p ≤ 0.0006) in colorectal adenocarcinoma.
Conclusion: Our data support a high utility of villin immunohistochemistry for the identification of tumors with gastrointestinal, pancreatobiliary, and yolk sac tumor origin. However, considering that at least a weak villin positivity in some tumor cells occurred in 54 different tumor categories, villin immunohistochemistry should be applied as a part of a marker panel rather than as a stand-alone marker.
Keywords: Villin; diagnostic marker; immunohistochemistry; tissue microarray; tumor types.