TET2 and myelodysplastic syndrome: Among the patients with MDS-IB1, MDS-IB2, or MDS-f, patients with MDS-IB2 exhibited higher frequencies of NRAS (9% vs. 2%, P = 0.019), TET2 (19% vs. 10%, P = 0.059), and monoallelic TP53 (7% vs. 1%, P = 0.031) mutations than did those with MDS-IB1.