Our analyses have confirmed that in the majority of cases (CX3CR1, FOXG1, G6PD, MAPK13, NOVA1, PNCK, SLC16A3, SLC2A1, SLC2A8, TBXA2R, TP73, TRIB2) the high synonymous-to-nonsynonymous and nonsense mutation rates could be interpreted as evidence for purifying selection during tumor evolution. The gene discussed is PNCK; the disease is neoplasm.