To clarify this point, we first compared tumor clustering according to their ACVR1 status, based on the transcriptional profiling of 193 BMP pathway target genes as a reliable readout of the pathway activation state, including notably the downstream transducers ID1, ID2, RUNX2, and GATA3 (see list in Supplementary file 1a). The gene discussed is ID1; the disease is neoplasm.