Utility of targeted gene sequencing to differentiate myeloid malignancies from other cytopenic conditions.

The National Heart, Lung, and Blood Institute-funded National MDS Natural History Study (NCT02775383) is a prospective cohort study enrolling patients with cytopenia with suspected myelodysplastic syndromes (MDS) to evaluate factors associated with disease. Here, we sequenced 53 genes in bone marrow samples harvested from 1298 patients diagnosed with myeloid malignancy, including MDS and non-MDS myeloid malignancy or alternative marrow conditions with cytopenia based on concordance between independent histopathologic reviews (local, centralized, and tertiary to adjudicate disagreements when needed). We developed a novel 2-stage diagnostic classifier based on mutational profiles in 18 of 53 sequenced genes that were sufficient to best predict a diagnosis of myeloid malignancy and among those with a predicted myeloid malignancy, predict whether they had MDS. The classifier achieved a positive predictive value (PPV) of 0.84 and negative predictive value (NPV) of 0.8 with an area under the receiver operating characteristic curve (AUROC) of 0.85 when classifying patients as having myeloid vs no myeloid malignancy based on variant allele frequencies (VAFs) in 17 genes and a PPV of 0.71 and NPV of 0.64 with an AUROC of 0.73 when classifying patients as having MDS vs non-MDS malignancy based on VAFs in 10 genes. We next assessed how this approach could complement histopathology to improve diagnostic accuracy. For 99 of 139 (71%) patients (PPV of 0.83 and NPV of 0.65) with local and centralized histopathologic disagreement in myeloid vs no myeloid malignancy, the classifier-predicted diagnosis agreed with the tertiary pathology review (considered the internal gold standard).

Interrogation of molecular profiles can help in differentiating between MDS and AML with MDS-related changes.

A subset of AML with myelodysplastic syndrome (MDS)-related changes (MRCs) occurs without a documented MDS phase. We studied genomic profile of 646 patients: 310 with MDS, 167 with AML without (w/o) MRC, 99 with primary (p) AML-MRC, and 70 with secondary (s) AML-MRC and sought to find differences in mutational patterns. Among the 32-myeloid associated genes studied, SF3B1 (p ≤ .001) was significantly mutated in higher proportion of patients with MDS, compared to other categories. NPM1 (p < .001), FLT3 ITD (p = .08), and NRAS (p = .02) mutations showed trend toward significance for AML w/o MRC, compared to other categories. In pAML-MRC, TP53 (p < .001) was significantly mutated in higher proportion of patients. Similarly, SETBP1 (p = .001), RUNX1 (p = .004), and SRSF2 (p = .04) mutations were more commonly seen in sAML-MRC. While these signatures may not be diagnostically discriminatory, they may help in disease categorization when other data are absent or in challenging cases.