COL1A1 and acute myeloid leukemia: To demonstrate the pivotal role of communication between osteoblasts and AML cells via the IL-6-IL-6R axis in vivo, IL-6R was knocked down by shRNA in BM-MNCs from WT-AML cells and subsequently transferred into lethally irradiated Col1a1-Cre;Tsc1fl/fl mice as a second transplantation (Figure 4H).