text_1: Combining phosphatidylinositide 3-kinase and MEK 1/2 inhibitors is effective at treating KRAS mutant tumors.
text_2: Studies using an H-Ras construct to constitutively and preferentially activate the three best-defined downstream targets of Ras, i.e., Raf, RalGDS, and PI3K, showed that mutant Ras mediates resistance through its ability to use multiple pathways for tumorigenesis.