SSTR2 and meningioma: Additionally, Seystahl et al. have also observed that the expression level of SSTR2 was not correlated with the WHO grade of meningiomas; yet the expression level of SSTR could be a predictive biomarker for the outcome of meningioma patients treated with PRRT; a higher expression of SSTR2 was revealed to be associated with better PFS after PRRT treatment (100).