Given that several papers have shown that factors within the epineurial compartment can lead to tumor progression (Fang et al., 2014; Kuzet and Gaggioli, 2016; McDonald et al., 2016); and that factors within the endoneurial compartment reduce Schwann cell proliferation (Parrinello et al., 2008), including CNTF, it is not surprising that we have found that iSCs are highly tumorigenic in the epineurial compartment compared to the endoneurial compartment. The gene discussed is CNTF; the disease is neoplasm.