Only knock-down of PTBP1 lowered the ratio of ITSN1-S/ITSN1-L significantly by remarkably increasing ITSN1-L as well as slightly decreasing ITSN1-S, consistent with the results shown in U87MG and 140 (a primary glioma cell line) cell lines (Supplementary Fig. S1) as well as in LN229 cell line (Supplementary Fig. S2). The gene discussed is ITSN1; the disease is glioma.