PTEN and Miyoshi myopathy: We observed that phosphorylation of the PI3K key downstream molecule, AKT, was found in only two MM cell lines, whereas further downstream, mTOR, PRAS40, S6, and 4E-BP1 phosphorylation, and the PI3K pathway suppressor, PTEN, were detectable in most MM cell lines (Figure 1B and Figure S6).