Detection of point mutations of the Axin1 gene in colorectal cancers.

Axin is a recently identified tumor suppressor that plays an important role in liver and colon cancers. To gain further insights into the structure and function of Axin in controlling cell growth, we analyzed 54 colorectal cancer tissues for mutations in AXIN1 gene. We employed PCR amplification with 23 sets of primers against introns that encompassed the whole coding region of AXIN1 followed by single-strand conformation polymorphism (SSCP) analysis. After subcloning and sequencing analysis of the reamplified DNA from the aberrant bands, we found, in addition to 3 silent mutations, 6 missense point mutations in different functionally important regions. The missense mutation rate is hence 11%, suggesting that Axin deficiency may contribute to the onset of colorectal tumorigenesis.