The presence of EGF and bFGF in NB medium have been regarded as necessary supplements to maintain the stem cell-like features and also to stimulate their growth.10 Moreover, it has been shown that GSCs cultured under these conditions preserve the genetic profile and characteristics of the human tumor of origin much better than cells cultured in serum monolayer conditions.11,12 However, research is still needed to define optimal conditions for GSCs cultures. The gene discussed is EGF; the disease is neoplasm.