Human sebaceous tumors harbor inactivating mutations in LEF1.

We found that one-third of human sebaceous tumors examined had double-nucleotide substitutions in the same LEF1 allele, irrespective of DNA mismatch repair status. The mutations impaired both LEF1 binding to beta-catenin and transcriptional activation, and are the first tumor-associated mutations that inactivate Wnt signaling. Mutant LEF1 not only inhibited expression of beta-catenin target genes but also stimulated expression of sebocyte markers, suggesting that it may determine the differentiated characteristics of sebaceous tumors.