NGS of the tumor showed an NRAS mutation (c.182A>G:p.Q61R) in 78%, a TP53 mutation (c.856G>A:p.E286K) in 60%, and a TERT gene mutation (1295250C>T) in 28% of the reads.
We studied the development of somatic mutations in t-MN, using a collection of follow-up samples from 14 patients with a primary hematologic malignancy, who developed a secondary leukemia (13 t-MN and 1 t-acute lymphoblastic leukemia), at a median latency of 73 months (range 18-108) from primary cancer diagnosis.Using Sanger and next generation sequencing (NGS) approaches we identified 8 mutations (IDH1 R132H, ASXL1 Y591*, ASXL1 S689*, ASXL1 R693*, SRSF2 P95H, SF3B1 K700E, SETBP1 G870R and TP53 Y220C) in seven of thirteen t-MN patients (54%), whereas the t-ALL patient had a t(4,11) translocation, resulting in the KMT2A/AFF1 fusion gene.
In contrast, independent of their HLA class I genotypes, the p53 Y</span>220C mutation frequency for all human tumors analyzed to date is approximately 1.5%.
The TP53 germ line mutation c.659A>C (p.Y220S) was identified in stored DNA from related patients with Li-Fraumeni syndrome (LFS) who died after developing clinically aggressive tumors.