Figure 4. Sequence analysis of the PTCH1 gene in medulloblastoma. (A) Microdissection of medulloblastoma and cartilage. Genomic DNA was isolated from the microdissected medulloblastoma and applied to direct sequence analysis. Genomic DNA was also isolated from the cartilage for comparison. (B) Direct sequence analysis of genomic DNA from unaffected donor (control), G11-iPSC cartilage and G11-iPSC medulloblastoma. G11-iPSC cartilage had a duplication of “GC” (shown in red), and G11-iPSC medulloblastoma showed LOH of the PTCH1 gene. (C) Direct sequence analysis of genomic DNA from G12-iPSC medulloblastoma. Sequences at the top and middle represent a germline mutation (c.3030_3031dupGC) and a somatic secondary mutation (c.3030_3031delGC), respectively. The minor wild-type sequence pattern (at the bottom) indicates contaminating non-medulloblastoma tissue.