Comparison of therapy-related and de novo core binding factor acute myeloid leukemia: A bone marrow pathology group study.

This multi-institutional study retrospectively evaluated clinicopathologic and genetic characteristics in 351 patients with core-binding-factor acute myeloid leukemia (CBF-AML), comprising 69 therapy-related (t-CBF-AML) and 282 de novo cases. The T-CBF-AML patients were older, had lower WBC counts, and slightly higher hemoglobin than patients with de novo disease. Secondary cytogenetic abnormalities were more frequent in patients with de novo disease than t-CBF-AML (57.1% vs 41.1%, P = .026). Patients with secondary cytogenetic abnormalities had longer overall survival (OS) than those without abnormalities (median 190 vs 87 months, P = .021); trisomy 8, trisomy 22, and loss of the X or Y chromosome were associated with longer OS. In the 165 cases performed of targeted gene sequencing, pathogenic mutations were detected in 75.7% of cases, and were more frequent in de novo than in therapy-related disease (P = .013). Mutations were found in N/KRAS (37.0%), FLT3 (27.8%), KIT (17.2%), TET2 (4.9%), and ASXL1 (3.9%). The TET2 mutations were associated with shorter OS (P = .012) while N/KRAS mutation was associated with longer OS in t(8;21) AML patients (P = .001). The KIT mutation did not show prognostic significance in this cohort. Although they received similar therapy, t-CBF-AML patients had shorter OS than de novo patients (median 69 vs 190 months, P = .038). In multivariate analysis of all patients, older age and absence of any secondary cytogenetic abnormalities were significant predictors of shorter OS. Among the t-CBF-AML subset, age and hemoglobin were significant on multivariate analysis. This study demonstrated that although de novo and t-CBF-AML patients share many features, t-CBF-AML patients have worse clinical outcome than de novo patients.

The Clinical Utility of the Genomic Prostate Score in Men with Very Low to Intermediate Risk Prostate Cancer.

PURPOSE: We retrospectively investigated the Genomic Prostate Score® assay in clinical practice at an urban tertiary care academic center. MATERIALS AND METHODS: We reviewed all Genomic Prostate Score results acquired during a 3-year period. Changes in patient NCCN® (National Comprehensive Cancer Network®) risk group, including very low, low, intermediate or high risk, and ultimate management decisions were recorded. RESULTS: Genomic Prostate Score risk stratification was performed in 134 men. According to the NCCN Guidelines®, 31 of the 134 men (23.1%) were at very low risk, 45 (33.6%) were at low risk and 58 (43.3%) were at intermediate risk. After adding the score the risk group changed in 32 of 134 patients (23.9%). The risk group did not change in the 31 men at very low risk. However, in the low risk group the risk changed in 19 of the 45 men (42.2%), including in 15 to very low and in 4 to intermediate risk. Also, in the intermediate risk group the risk changed in 13 of the 58 men (22.4%), including to low in 12 and to high risk in 1. Nine of the 15 men (60%) in whom risk changed from low to very low elected active surveillance. Nine of the 12 patients (75%) at intermediate risk in whom risk changed to low risk elected active surveillance, 2 (16.7%) elected definitive therapy and in 1 (8.3%) the choice was unknown. Of the 45 men at intermediate risk in whom risk was unchanged 28 (62.2%) elected definitive therapy, 12 (26.0%) elected active surveillance and in 5 (11.1%) the choice was unknown. Of the 4 men upgraded from low to intermediate risk after adding the genomic prostate score 2 elected definitive therapy and 2 chose active surveillance. CONCLUSIONS: The Genomic Prostate Score has limited clinical usefulness in patients at very low risk since the NCCN risk group did not change. While it may be more useful for men at low and intermediate risk, for 32 (31%) of whose risk group was reclassified, clinical management decisions did not always appear to reflect these changes.

The use of BRAF V600E mutation-specific immunohistochemistry in pediatric Langerhans cell histiocytosis.

BRAF p.V600E mutations are detected in greater than 50% of pediatric Langerhans cell histiocytosis (LCH) lesions. However, the use of mutation-specific BRAF V600E immunohistochemistry (IHC) as a surrogate for molecular testing in pediatric LCH is unknown. We tested the mutation-specific BRAF V600E monoclonal antibody (clone VE1) in formalin-fixed, paraffin-embedded LCH samples from 26 pediatric patients (14 males and 12 females, ages 7 mo-17 y) using allele-specific real-time polymerase chain reaction (PCR) with a limit of detection of 0.5% as the comparative gold standard. BRAF VE1 staining was scored for both intensity (0-3+) and percentage of immunoreactive tumor cells (0%-100%). BRAF VE1 immunoreactivity was determined using both lenient (≥1+, ≥1%) and stringent (≥2+, ≥10%) scoring criteria. Using lenient-scoring criteria, we found that the sensitivity and specificity of IHC compared with allele-specific real-time PCR were 100.0% and 18.2%, respectively. The poor specificity of lenient IHC analysis was attributable to weak, 1+ staining in both BRAF-mutated and wild-type LCH. Using stringent-scoring criteria, we found that specificity improved to 100.0% at the expense of sensitivity that decreased to 80.0%. Stringent scoring generated 3 false-negative results, but in all cases, neoplastic tissue comprised less than 5% of the stained section and/or the specimen was decalcified. In conclusion, highly sensitive molecular assays remain the gold standard for BRAF mutation analysis in LCH paraffin-embedded lesions. To avoid false-positive results, unequivocal VE1 staining of 2+ intensity in greater than or equal to 10% neoplastic histiocytes is required. However, negative VE1 results require additional studies to exclude false-negatives, and stringent-scoring criteria may not be optimal for scant or decalcified specimens.

Presence but not number of secondary type mutations influences outcome in de novo AML without MDS-associated or recurring cytogenetic abnormalities.

A group of gene mutations has been identified to be strongly associated with secondary acute myeloid leukemias (AML) arising from prior myeloid neoplasms. The International Consensus Classification (ICC) and proposed 5th edition of the World Health Organization (WHO) classification differ by inclusion of RUNX1. A recent study suggested that having two or more secondary mutations is associated with a particularly poor prognosis. In a study of 294 de novo AML patients, we found that patients with at least one ICC-defined secondary mutation had shorter survival when compared to those without secondary mutations, and ICC/WHO groups of two or more mutations did not predict for worse outcomes.

Clinicopathologic and Molecular Analysis of Normal Karyotype Therapy-Related and De Novo Acute Myeloid Leukemia: A Multi-Institutional Study by the Bone Marrow Pathology Group.

PURPOSE: Therapy-related acute myeloid leukemias (t-AML) are a heterogenous group of aggressive neoplasms that arise following exposure to cytotoxic chemotherapy and/or ionizing radiation. Many therapy-related myeloid neoplasms (t-MN) are associated with distinct chromosomal aberrations and/or TP53 alterations, but little is known about the clinicopathologic and molecular features of normal karyotype t-AML (NK-t-AML) and whether this t-MN subtype is distinctly different from NK de novo AML (NK-dn-AML). METHODS: This multi-institutional study by the Bone Marrow Pathology Group retrospectively evaluated clinicopathologic and molecular characteristics of 335 patients with NK-AML, comprising 105 t-AML and 230 dn-AML cases. RESULTS: Patients with t-AML compared with dn-AML exhibit significantly shorter overall survival (OS; median months: 17.6 v 44.2; P < .0001) and relapse-free survival (RFS; median months: 9.1 v 19.2; P = .0018). Frequency of NPM1, FLT3, KRAS, and GATA2 mutations were significantly different in NK-t-AML compared with NK-dn-AML (NPM1 35% v 49%; P = .0493; FLT3 23% v 36%; P = 0494; KRAS 12% v 5%; P = .0465; GATA2 9% v 2% P = .0105), while TP53 mutations were rare. Patients with t-AML more often stratified into intermediate or adverse 2017 ELN genetic risk groups. Favorable ELN risk predicted favorable OS (hazard ratio [HR], 0.4056; 95% CI, 0 to 0.866; P = .020) and RFS (HR, 0.355; 95% CI, 0 to 0.746; P = .006). Among all patients with NK-AML, stem-cell transplant and favorable ELN risk both significantly affected RFS, while therapy-relatedness and age had a borderline significant impact on OS (HR, 1.355; 95% CI, 0.975 to 1.882; P = .070). CONCLUSION: To our knowledge, this is the largest study to date to comprehensively evaluate NK-t-AML and provides a framework that may inform our understanding of NK-t-AML disease biology and could potentially help guide therapeutic management and improved disease classification in t-MNs that lack cytogenetic aberrations.