K-RAS-2 AND P53 GENOTYPING OF INTESTINAL-TYPE ADENOCARCINOMA OF THE NASAL CAVITY AND PARANASAL SINUSES

Intestinal-type adenocarcinoma (ITAC) of the nasal cavity and paranasa l sinuses is an uncommon neoplasm manifesting a variety of histologic growth patterns, most of which are reminiscent of colorectal adenocarc inoma To determine whether this morphologic resemblance is mirrored in equivalent genetic alterations, a series of ITAC was genotyped using archival, formalin-fixed tissues for point mutational damage in K-ras- 2 oncogene and p53 tumor suppressor gene, forms of DNA damage frequent ly found in colorectal adenocarcinoma In contrast to colorectal adenoc arcinoma, which demonstrates K-ras-2 mutation in about 50% of cases, I TAC showed no evidence of K-ras-2 mutation, p53 mutations were present in 18% of ITAC (2 of 11) compared to more than 75% incidence of p53 m utation seen in colorectal adenocarcinoma Fifty-eight percent of ITAC demonstrated scattered positive p53 immunohistochemical nuclear staini ng, but no mutations were identified in exon-5 through exon-8 by genot yping, There was no specific p53 alterations with respect to histologi c subtype of ITAC, Although ITAC and colorectal adenocarcinoma are his tologically similar, there are important differences at the genetic le vel based on expression of K-ras-2 and p53 abnormalities.