MRC1 and Polymerase proofreading-related adenomatous polyposis: Since high grade glioma (HGG), reported so far in 2/47 patients with PPAP [3], may belong to the tumor spectrum of PPAP, this diagnosis should also be considered in pediatric and young adult patients with HGG (and possibly other cancers), who show signs reminiscent of CMMRD but lack diagnostic hallmarks of CMMRD, such as MMR protein expression loss and other diagnostic features [20], and/or biallelic MMR gene mutations.