POLG and cancer: We observed a spectrum of candidate pathogenic somatic point mutations in cancer genes in this set of samples (Supplemental Fig. 5, Supplementary Data 12) including shared and private mutations predominantly in TP53 (8/10) in addition to individual cases with ARID1B, DNMT1, KMT2D, POLG, PPM1D, PREX2, RB1, or RET mutations.