Since RUNX2 mRNA was increased in TB lungs, we further performed immunohistochemical analysis to examine the abundance of RUNX2 and p-SMAD1/5/9 for indicating the activation of bone morphogenetic protein (BMP)/SMAD signaling pathway, which regulates RUNX2 expression and plays a crucial role in osteogenesis36,37. Here, SMAD1 is linked to tuberculosis.