STAT3 and myeloid sarcoma: Interestingly, we observed that activated levels of p-STAT3 and p-STAT5 in NK cells from MS subjects positively correlate with disease duration (r = 0.34, p = 0.035 and r = 0.43, p = 0.0075) but not with age (r = − 0.06, p = 0.73 and r = 0.06, p = 0.73), suggesting that changes in the susceptibility to STAT phosphorylation might reflect a physiological mechanism associated with the disease, independent of aging.