Background. Intestinal-type adenocarcinoma (ITAC) of the nasal cavity and paranasal sinuses shows microscopic features indistinguishable from colorectal cancer. Our aim was to verify whether the morphologic resemblances mirror genetic profile similarities. Methods. Twenty consecutive surgically treated ITAC cases, previously investigated for p16 INK4a and TP53, were investigated for hMLH1, hMSH2, and β-catenin immunoreactivity, and for adenomatous polyposis coli (APC), K-ras, and BRAF gene mutations. Results. One case was immunonegative for both hMLH1 and hMSH2, and 12 tumors (40%) revealed a strong β-catenin overexpression. No BRAF and APC truncating mutations were identified, whereas K-ras mutations were detected in 9 ITACs (50%). Conclusions. Our data confirm the phenotypic similarities at the genetic level between colorectal cancer and ITACs showing deregulation of K-Ras/BRAF and loss of heterozygosity (LOH) of chromosome 18q. By contrast, both frequency rate and type of inactivation of the APC-β-catenin pathway differ in the 2 tumors, suggesting different gatekeeper events in the early development of ITAC (p16 INK4a and TP53) and colorectal cancer (APC).
- APC/β-catenin pathway, K-ras/BRAF pathway
- Colorectal cancer
- Mismatch repair genes
ASJC Scopus subject areas