Absolute quantification of mutations at Hras codon 61 was determined using a 3D Digital PCR System, and Hras mutational frequency was below the detection limit of the digital PCR system (0.1%) not only in DMBA-treated organoids, but also in the organoid-derived DMBA-induced adenocarcinomas in the nude mouse subcutis (Figure 2B). Here, HRAS is linked to adenocarcinoma.