Abstract
WNT signalling orchestrates a number of developmental programs. In response to this stimulus, cytoplasmic β-catenin (encoded by CTNNB1) is stabilized, enabling downstream transcriptional activation by members of the LEF/TCF family. One of the target genes for β-catenin/TCF encodes c-MYC, explaining why constitutive activation of the WNT pathway can lead to cancer, particularly in the colon. Most colon cancers arise from mutations in the gene encoding adenomatous polyposis coli (APC), a protein required for ubiquitin-mediated degradation of β-catenin, but a small percentage of colon and some other cancers harbour β-catenin-stabilizing mutations (refs 8-17). Recently, we discovered that transgenic mice expressing an activated β- catenin are predisposed to developing skin turmours resembling pilomatricomas. Given that the skin of these adult mice also exhibits signs of de novo hair-follicle morphogenesis, we wondered whether human pilomatricomas might originate from hair matrix cells and whether they might possess β-catenin-stabilizing mutations. Here, we explore the cell origin and aetiology of this common human skin tumour. We found nuclear LEF-1 in the dividing turnout cells, providing biochemical evidence that pilomatricomas are derived from hair matrix cells. At least 75% of these tumours possess mutations affecting the amino-terminal segment, normally involved in phosphorylation-dependent, ubiquitin-mediated degradation of the protein. This percentage of CTNNB1 mutations is greater than in all other human tumours examined thus far, and directly implicates β-catenin/LEF misregulation as the major cause of hair matrix cell tumorigenesis in humans.
Original language | English |
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Pages (from-to) | 410-413 |
Number of pages | 4 |
Journal | Nature Genetics |
Volume | 21 |
Issue number | 4 |
DOIs | |
State | Published - Apr 1999 |
Externally published | Yes |
Bibliographical note
Funding Information:We thank A. Christiano, M. Tharp and R. Elenitsas for tissue samples; R. Grosschedl for LEF-1 antibody; and M. Medenica for providing H&E-stained slides of normal human scalp skin. This work was supported in part by the National Institutes of Health (NIH-RO1-AR31737 and NCI-P50DE/CA-11921). E.F. is an Investigator of the Howard Hughes Medical Institute. E.F.C. is supported by the Howard Hughes Medical Institute Postdoctoral Research Fellowship for Physicians.