They were almost undetectable in cells inside the peri-necrotic niche, while their expression was observed in association with Ki-67-positive proliferating glioma cells adjacent to the peri-necrotic niche (Fig. 1a–f) as well as the non-necrotic areas distant from the large ischemic necroses (Fig. 1k–p). The gene discussed is MKI67; the disease is central nervous system cancer.