Circulating bone formation (P1NP) and bone resorption (CTX) markers were not different between genotypes at 5 and 15 weeks (Supplementary information, Fig. S2b, c) and mRNA expression of the major collagens Col1a1, Col1a2 and Col3a1 appeared comparable in tumor-bearing bones at 5 weeks and in primary OS cells (Supplementary information, Fig. S2d, e). Here, COL3A1 is linked to neoplasm.