POLR2A and neoplasm: In contrast, all genetic variants of the NF2, POLR2A, and PTEN genes found in these three patients in which paired tumor and blood DNA were studied, and were absent in blood DNA and restricted to the tumor cell DNA where they were detected at frequencies ≤40%—except for NF2 tumors with -22/del(22q), suggesting these later variants would correspond to tumor-specific non-synonymous genetic variants, e.g., somatic mutations.