Expression of CD44 in duct cell carcinomas and in intraductal neoplasms of the pancreas.

The expression of alternatively spliced CD44 isoforms, especially so-called variant exons v5 and v6, has been shown to correlate with the progression of a number of human cancers examined the expression of standard CD44 and CD44 variants with exons v5 and v6 in 28 cases of human pancreatic tumors (16 cases of invasive duct cell adenocarcinoma and 12 cases of intraductal neoplasms) by immunohistochemistry using exon specific monoclonal antibodies. The expression of standard CD44 was frequently observed in both invasive duct cell carcinomas and intraductal neoplasms. The expression of CD44 variants (v5 and v6) was also seen in almost all duct cell carcinomas. In contrast, intraductal neoplasms infrequently expressed CD44-v5 and -v6, particularly v6 exon. Expression of CD44-v5 and v6 was a common characteristic of invasive cancer, while it was not so prominent in intraductal neoplasm. These findings may be related to the invasiveness of duct cell carcinoma and/or the benign biological behavior of intraductal neoplasm of the pancreas.