As a complementary approach to assess the importance of Akt1 signalling in NSCLC TICs we suppressed Akt1 expression in an established lung cancer cell line (NCI-H460) that harbours an activating mutation of PIK3CA (E545K) and in one primary short-term culture (PEd/10) derived from pleural effusions of lung cancer patients that engraft very efficiently (10–16 weeks latency) giving rise to adenocarcinoma [24]. This evidence concerns the gene PIK3CA and Pleural effusion.