In the “water-burst” method, we could detect even a small number of cells with a homozygous KRAS mutation at codon 12, in as low as 20 cells (= 40 copies) in 4,000 normal cells with wild-type KRAS, showing that it was feasible to detect dPCR-based direct driver mutations in crude tumor tissues. This evidence concerns the gene KRAS and neoplasm.