Villin expression in human tumors: a tissue microarray study on 14,398 tumors

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. 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. 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 (<i>p</i> ≤ 0.0006) in colorectal adenocarcinoma. 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.