In lower grade glioma, the CCN1 high expression group tended to have a high frequency of PIK3R1Met326Ile, but it was not statistically significant (Table 3 and Supplementary Table S1; astrocytoma, p = 0.2488; oligodendroglioma, p = 0.3158, Fisher’s exact test). Here, CCN1 is linked to oligodendroglioma.