S100A4 and Osteopenia: The relative levels of mRNAs of calcium-binding/associated proteins, annexin A1, S100A4, and TMEM64, in isolated PBMC preparations were each significantly different between nonosteoporosis control, osteopenia, or osteoporosis groups of participants (one-way ANOVA, annexin A1 mRNA, Figure 1(a), F(2 : 85) = 16.7, P < 0.0001; TMEM64 mRNA, Figure 1(b), F(2 : 84) = 4.13, P = 0.0195; S100A4, Figure 1(c), F(2 : 84) = 3.4, P = 0.039).