RAF1 and squamous cell lung carcinoma: Additionally, the PI3K/Akt/mTOR pathway is also altered in NSCLC, especially in squamous cell lung cancer;26 the crosstalk between Ras/Raf/MEK and PI3K/Akt/mTOR signalling pathways makes NSCLC treatment even more challenging, since inhibiting one pathway may lead to corresponding activation of the other due to blocking negative regulation.