Fig. 2

Intra-tumoral heterogeneity in a 4-year old male with DIPG (Patient 3). Each row represents a distinct disease location, including four different areas in the primary tumor, one contiguous lesion in the right basal ganglia, and one metastatic leptomeningeal lesion. a H&Es of each tumor location demonstrate WHO grade IV histology in all except the right basal ganglia lesion (WHO grade III), b P53 IHC demonstrates variable positivity, c PDGFRA FISH demonstrates gain or amplification in 3 of 4 sites within the pontine tumor, gain in the contiguous right basal ganglia lesion, and amplification in the metastatic leptomeningeal lesion, d PDGFRA ddPCR demonstrating PDGFRA mutation observed in the right posterior pons, e H3F3A was mutated in all samples as demonstrated by Sanger sequencing, f sample location taken from fresh (“Primary Pons”, Row 1) or fixed tissue (remaining rows) at autopsy corresponding to tumor location identified on post-mortem MRI imaging (g). Because post-mortem imaging was only performed on fixed tissue, MRI imaging for the fresh tissue sample (“Primary Pons”, Row 1) was a pre-mortem MRI performed approximately 6 weeks prior to death