The prominence of Pdgfra and Pdgfrb in cluster 4 (Figure S1) of the spleen underscores the activation of platelet‐derived growth‐factor (PDGF) signaling, a major driver of fibroblast proliferation and ECM deposition, aligning with findings in murine myelofibrosis models (Herrera et al. 2018). The gene discussed is PDGFRA; the disease is myelofibrosis.