Linear regression analysis confirmed a significant relationship between BMI and CCN3 plasma levels in age- and sex-matched healthy controls, but this relationship was absent in MS patients (Fig. 2d,e; HC; r2 = 0.427, slope = 1.294 ± 0.50, p = 0.029 MS; r2 = 0.018, slope = − 0.113 ± 0.17, p = 0.505). The gene discussed is CCN3; the disease is myeloid sarcoma.