KRAS and neoplasm: Expanding the use of the qRT-PCR assay to examine over 90 tumor nodules from 14 mice, 8 of which were tri-transgenics, confirmed that tumors from tri-transgenic mice almost always contained RNA from a single transgenic oncogene, either EGFR or Kras, and the amounts of RNA were similar to those found in tumors from the bi-transgenic animals (Figure 2C).