PTCH is also mutated in up to 70% of sporadic BCC (Gailani et al, 1996; Hahn et al, 1996; Johnson et al, 1996; Unden et al, 1996; Wolter et al, 1997; Aszterbaum et al, 1998; Ratner et al, 2001; Zhang et al, 2001; Kim et al, 2002; Reifenberger et al, 2005; Teh et al, 2005; Heitzer et al, 2007). Here, PTCH1 is linked to skin basal cell carcinoma.