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. Here, PTH is linked to sarcoma.