Undetectable or very low level of TGF-β1 protein by western blotting in all the untreated human VS samples observed by us (Figure 4a–c) is in agreement with the previous reports where TGF-β1 and TGF-β2 mRNA were shown to be down-regulated in vestibular schwannoma as compared to the peripheral nerve samples [24], and no TGF-β1 expression was found in a cohort of 34 VS tissues [25]. This evidence concerns the gene TGFB2 and Vestibular schwannoma.