CD44 and cancer: In two well-established NSCLC cell lines, H1975 and H1299, stem-like CD44+/CD90+ cells, which represented 1% of the total cell population, yielded elevated protein levels of mEAK-7, S6K2, n-cadherin (marker for the epithelial-mesenchymal transition state in cancer stem cells), and phosphorylated S6 and 4E-BP1, indicating activated mTOR signaling with higher invasive potential compared to CD44-/CD90- cells (14).