Figure 1. Identification of PTCH1 mutations in KC30. Nonsense mutation (c.403C>T) showed a homozygous pattern in DNA samples of KCOT, but was absent in peripheral blood DNA (left). Two concomitant polymorphisms (c.2913T>C; c.3141T>G) were homozygous in the tumor, but heterozygous in blood DNA (right), suggesting allelic loss (W, wild-type; T, KCOT tissue; B, peripheral blood).