Wnt-pathway activation in intestinal-type sinonasal adenocarcinoma

Intestinal-type sinonasal adenocarcinoma (ITAC) is an epithelial cancer of the sinonasal sinuses that shows histological similarity to colorectal cancer (CRC) and share chronic inflammation as a possible etiological factor. The Wnt-pathway is one of the most important tumourigenic pathways in CRC. The aim of this study was to investigate if the Wnt-pathway is activated in ITAC.

Protein expression profiles of E-cadherin, β-catenin, c-myc and cyclin D1 were analysed by immunohistochemistry in 83 samples of ITAC, organized into tissue microarray blocks.

Nuclear β-catenin expression was observed in 31% of the cases and was twice as frequent in papillary/colonic ITAC compared to solid/mucinous subtypes. Loss of membranous β-catenin staining occurred in 24% and loss of membranous E-cadherin in 6% of the cases and this was more prominent in mucinous types. Strong c-myc and cyclin D1 expression was observed in 30% and 4% of the cases, respectively. Nuclear β-catenin expression was significantly related to poor clinical outcome, independent from established factors as tumour stage and histological type.

The presence of nuclear β-catenin in 31% of patients with ITACs indicated that in a subset of patients, the Wnt-pathway is active and conveys a worse prognosis.