TBX21 and myeloid sarcoma: Results: Strong association between the wild -1514T allele and MS susceptibility was found with the allelic frequency of 99.6% in patients vs. 95.1% in controls (P = 0.002), and the CC genotype frequency of the TBX21 polymorphism (-1514T > C) reported potential protective effect against the disease (P = 0.014).