PTCH1 and cancer: Recently, it was reported that, in Ptch1 heterozygous (Ptch1+/–) mice of the medulloblastoma tumor model and Eker (Long Evans Tsc2+/–) rats of the renal cancer model, LOH analysis can be used to estimate whether deletion of a wild-type allele containing a cancer-causing gene region (Deletion), duplication of a mutant allele with a mutation in a cancer-causing gene occurred (Duplication), or no abnormality (Unidentified) occurred, and that the Deletion type is increased in a dose-dependent manner [4–6].