In two of the four cases, the TP53 mutation present as the sole variant in the CNS metastasis was also detected in the primary cancer, in both cases in the presence of other mutations: in Case 19P, three mutations (Pro300Leu, Ser260Phe and the complex mutation Ser183Ter) were detected, but only Ser183Ter (homozygous) was detected in the CNS metastasis 19BM. The gene discussed is TP53; the disease is cancer.