In particular, perhaps the key source of malignancy in diffuse gliomas carrying IDH gene mutations is not only an increase in the number of cells with stem properties, as was established earlier, but also a gradual adjustment of a part of the cell mass to an increase in tumor proliferative activity, which entails an inevitable increase in the need for oxygen, coupled with other nutrients, forming a hypoxic environment for neoplasm cells. The gene discussed is IDH2; the disease is neoplasm.