Cellular Variations/language *New German study finds Kras stimulation in Pancreatic cancer is not the same as Kras stimulation in the lung and therefore PI3K expression will not have same implications

Selective Requirement of PI3K/PDK1 Signaling for Kras Oncogene-Driven Pancreatic Cell Plasticity and Cancer
Stefan Eser, Nina Reiff, et al.

Read it.  It tells you that not only the implications of a stimulation of one molecule change with the tissue because of tissue specific genetic silencing ,  but also changes can occur on different RAS family member (NRas or Hras) leading to different meaning in terms of consequence for the cell.
Another discrimination level is that many types of stimulation can induce the same pathway.  C-JUN can be induced by radiation, chemical, hypoxia or infection.  Any thing that is considered stressful, including lack of extracellular stimulation.  This last point is very important in the Central nervous system where pre-synaptic stimulation is critical for post synaptic neurons.  Lack of stimulation induces an inflammatory process in both the neuron and the glial cell.  In the glial cell, the myelin sheath is scarily attacked or no longer formed.
The duplicity phenomena occurs particularly at the cellular membrane where many receptors would be stimulated by several stimulants and vice versa (many stimulants for same receptor).  Only the cell and its tissue type know what to give out!

*New study concurs that mammogram should be done every 2 years and after 50 years of age.   That only those women with dense breasts should start at 40 years of age and annually.  The controversy dance is fueled once again and I don't blame anyone!  We have seen cases of course which did not fit these prescription.  Why change things that work.