FOS and sarcoma: In addition to the GNAS mutation analysis above, other molecular mechanisms underlying sarcoma development in FD, including aberrant TP53 (Sugiura et al., 2018; Yap et al., 2020), multiple chromosomal abnormalities (Hatano et al., 2014; Jhala et al., 2003), increased cell proliferation (Sugiura et al., 2018; Yap et al., 2020), MDM2 (Sugiura et al., 2018), c‐fos (Kanazawa et al., 2009), PTH/PTHrP (Kanazawa et al., 2009) and karatins (Zreik et al., 2017), have been reported in case reports using traditional chromosome abnormality methods and IHC, which can reveal only limited information.