HSP90AA1 and myeloid sarcoma: Specifically, we found that ARL17B (see above), HES1 (encoding a basic helix-loop-helix transcription factor) and SRPX2 (encoding a protein relevant for glutamatergic synapse formation) were selectively downregulated in spinal AS-CD44 cells in MS; conversely, known stress marker genes such as HSP90AA1, HSPB1 and FTL appeared to be upregulated in spinal MS astrocytes (Fig. 3k).