Therefore, to analyze how chronic hypoxia affect MM cells in vitro, four MM cell lines (RPMI-8226, LP-1, OPM-2 and KMS-12-BM) were adapted to physiological oxygen concentration in vitro (1% O2 and 5% CO2) over a period of 7 days and subsequently tested for the mRNA expression of predefined marker genes for acute hypoxia (Egl-9 family hypoxia inducible factor 1, EGLN1 (PHD2); adrenomedullin, ADM) and chronic hypoxia (H4 clustered histone 1, H4C1; osteoclast stimulating factor 1, OSTF1) [44,45] (Figure 1). Here, OSTF1 is linked to Miyoshi myopathy.