Valkonen M, et al. - Researchers performed this retrospective study assessing the content of hyaluronan, its cell surface receptor CD44, and the expression of hyaluronan metabolizing enzymes in diffusely infiltrating astrocytomas. Analyzing material consisting of 163 diffusely infiltrating astrocytomas (WHO grades II-IV), they noted strong expression of hyaluronan and CD44 in astrocytic gliomas. However, no correlation of their expression with WHO grade or any other clinicopathological parameters was observed. Isocitrate dehydrogenase1 (IDH1) negative tumors exhibited high HAS2 (hyaluronan synthases 2) staining intensity suggesting a prognostic significance of HAS2 in diffusely infiltrating astrocytomas.