Basal cell carcinoma occurring in multiple familial trichoepithelioma: detection of loss of heterozygosity in chromosome 9q

Abstract

Basal cell carcinoma (BCC) occasionally arises from the preexisting lesions of multiple familial trichoepithelioma (MFT). 1 The gene for BCC has been assigned to chromosome 9q22.3-q31, 2 and the gene for Bazex-Dupre-Christol syndrome, characterized by the early onset of multiple BCCs, has been mapped to chromosome Xq24-q27.1. 3 Recently, we carried out a linkage analysis in 3 families with MFT and mapped the gene for MFT to chromosome 9p21. 4 Therefore, trichoepithelioma does not seem to be allelic with BCC despite their histological similarities. To assess the involvement of the BCC genes in the development of BCC in MFT lesions, we examined the possibility of loss of heterozygosity in 2 different BCC specimens from the same patient using microsatellite markers of chromosomes 9q22-q31, Xq24-q27, and 9p21. Only the markers of chromosome 9q22-q31, the locus for sporadic BCCs and nevoid BCC syndrome, showed loss of heterozygosity in 1 of the 2