SSTR2 and neoplasm: In addition, spheroids generated from WHO grade 1 and 2 tumours showed a similar immunoscore of the proliferation marker Ki67 as compared to matched patient tissues (Fig. 3a, b) and retained expression of somatostatin receptor 2 (SSTR2), a marker commonly expressed by meningioma cells, although this staining was weaker in spheroids compared to tissue (average immuno score of 1.6 in spheroids compared to average score of 3.3 in tissue) (Fig. 3c).