Clinicopathologic characteristics of myeloid neoplasms that harbor both a DDX41 germline and an acquired DDX41 genetic alteration

Introduction/Objective

Myeloid neoplasms associated with DDX41 germline genetic alterations are becoming increasingly recognized as a unique subset of hematologic cancer predisposition syndromes. As such, we sought to review their clinicopathologic characteristics.

Methods/Case Report

We searched our next-generation sequencing database for cases with two DDX41 variants; one variant at heterozygous variant allele fraction (VAF) indicating known or putative germline status, and second variant at low VAF consistent with an acquired subclone. We reviewed the clinicopathologic features.

Results (if a Case Study enter NA)

We identified 18 cases - male:female ratio 2.6:1, average age at presentation, 69 years (range 57-89). The diagnoses included no diagnostic abnormality (3), MDS-MLD (1), MDS-EB1 (1), increased blasts only(5-19%) (7), and AML (6). All had anemia [average hemoglobin (10.2) (range 6.5-12.9 g/dL)], 17/18 with thrombocytopenia [average 87 (range 22-222 K)], 17/18 with neutropenia [average absolute neutrophil count (ANC) (819) (range 90-1800)] and 13/18 with macrocytosis [average (101.5) (range 83.7-114 fL)]. Bone marrow cellularity (corrected for increased blasts >20%) was predominantly hypocellular (11/19) followed by normocellular (5/19). 3/19 cases showed erythroid dysplasia; no cases demonstrated granulocytic dysplasia; 7/19 cases showed megakaryocytic dysplasia. Of non-AML cases, 8/12 cases showed increased blasts [average 10% (range 5-19%)]. Of 4 cases without an increase in blasts, 1 showed MDS, 2 no dysplasia [1 -ANC of 666 and preserved platelets (222); 2- thrombocytopenia with preserved ANC (1800)] and 1 had slight megakaryocytic atypia. 16/17 cases were karyotypically normal. 14/18 of the patients are alive (median follow-up, 48) (8-125 months).

Conclusion

This cohort finds that myeloid neoplasms arising from DDX41 germline predisposition syndrome tend to present in older individuals, have infrequent dysplasia and are associated with a prolonged clinical course despite elevated blast counts at diagnosis. Recognition of these disorders is challenging and DDX41 testing should be included as part of genetic profiling. The presence of a suspected DDX41 germline variant may prompt confirmatory and familial testing, particularly in the event a hematopoietic transplant is a treatment option.

Panel sequencing for clinically oriented variant screening and copy number detection in 142 untreated multiple myeloma patients

We employed a customized Multiple Myeloma (MM)-specific Mutation Panel (M³P) to screen a homogenous cohort of 142 untreated MM patients for relevant mutations in a selection of disease-specific genes. M³Pv2.0 includes 77 genes selected for being either actionable targets, potentially related to drug–response or part of known key pathways in MM biology. We identified mutations in potentially actionable genes in 49% of patients and provided prognostic evidence of STAT3 mutations. This panel may serve as a practical alternative to more comprehensive sequencing approaches, providing genomic information in a timely and cost-effective manner, thus allowing clinically oriented variant screening in MM.

Minimal residual disease detection in childhood precursor-B-cell acute lymphoblastic leukemia: relation to other risk factors. A Children's Oncology Group study

Minimal residual disease (MRD) can be detected in the marrows of children undergoing chemotherapy either by flow cytometry or polymerase chain reaction. In this study, we used four-color flow cytometry to detect MRD in 1016 children undergoing therapy on Children's Oncology Group therapeutic protocols for precursor-B-cell ALL. Compliance was excellent, with follow-up samples received at the end of induction on nearly 95% of cases; sensitivity of detection at this time point was at least 1/10,000 in more than 90% of cases. Overall, 28.6% of patients had detectable MRD at the end of induction. Patients with M3 marrows at day 8 were much more likely to be MRD positive (MRD+) than those with M2 or M1 marrows. Different genetically defined groups of patients varied in their prevalence of MRD. Specifically, almost all patients with BCR-ABL had high levels of end-of-induction MRD. Only 8.4% of patients with TEL-AML1 were MRD+>0.01% compared with 20.3% of patients with trisomies of chromosomes 4 and 10. Our results show that MRD correlates with conventional measures of slow early response. However, the high frequency of MRD positivity in favorable trisomy patients suggests that the clinical significance of MRD positivity at the end of induction may not be the same in all patient groups.

Utility of immunohistochemistry in bone marrow evaluation of T-lineage large granular lymphocyte leukemia

Although T-lineage large granular lymphocyte (LGL) leukemia has been described for over 20 years, many patients with this neoplasm go unrecognized. Chief among the difficulties in diagnosing this entity is that the morphologic features are nonspecific and that it is difficult to distinguish it from reactive processes. The purpose of this study was to examine the histologic and immunophenotypic appearance of T-LGL leukemia in the peripheral blood and bone marrow, and to determine what features may suggest that ancillary studies such as flow cytometric and molecular analysis should be pursued to make a definitive diagnosis. We took a multidisciplinary approach by using morphology, immunoperoxidase staining, flow cytometric analysis, and molecular studies on 9 cases of T-lineage LGL leukemia. Our findings indicate that T-lineage LGL leukemia typically infiltrates the marrow diffusely. Most cases show a hypercellular marrow with an increase in myeloid precursors relative to the mature cells (i.e., an inversion of the myeloid maturation pyramid) and a decreased myeloid:erythroid ratio. Neutropenia without a left shift is usually seen in the peripheral blood. The tumor cells are usually CD3+, CD8+, CD57+, and TIA-1+. Most notably, the number of CD3+ T cells per high-power field is markedly elevated in T-LGL leukemia compared with normal, reactive, and pathologic marrows with neutropenia (mean values, 559 cells/mm(2) v. 7/mm(2), 11/mm(2), and 263/mm(2), respectively, P<.01). Moreover, CD57 staining also shows an increase in positive cells in T-LGL cases in comparison with normal, reactive, and pathologic marrows with neutropenia. Taken together, these findings indicate immunoperoxidase findings may be a useful tool to identify cases that should proceed to molecular or flow cytometric analysis.

Patient and tumor characteristics of colon cancers with microsatellite instability: a population-based study

Molecular screening for microsatellite instability (MSI) in colon cancers has been proposed to identify individuals with hereditary nonpolyposis colorectal cancer. To date, most reports of MSI in colorectal cancer have been based on studies of clinical case series or high-risk families. We examined the proportion of incident colon cancers in the general population that exhibit MSI by patient and tumor characteristics. We interviewed 201 colon cancer cases ascertained by the New Mexico Tumor Registry in the metropolitan Albuquerque area for demographic information, lifestyle factors, medical history, and family cancer history. Paired normal and tumor tissue specimens were obtained for each case. Three microsatellite markers were used; instability was defined as observed alteration at two or more loci. Overall, 37 of 201 (18%) colon cancers exhibited instability. MSI was more common among cases >70 years (26%) and most common among cases >80 years (38%). MSI was significantly associated with tumors in the proximal colon and with later stage and poor differentiation among cases >70 years. MSI was not associated with a history of polyps. Family history of colorectal cancer was associated with MSI only among cases <50 years. When all factors were analyzed jointly in a regression model, proximal subsite and poor differentiation remained significantly associated with MSI. One patient, whose tumor exhibited MSI, fulfilled the Amsterdam Criteria for hereditary nonpolyposis colorectal cancer. Our study provides a population-based estimate of MSI in colon tumors and a representative estimate of the proportion of colorectal cancer patients in the general population who consent to be interviewed for family cancer history and to have biological samples analyzed.

Association of PML-RAR alpha fusion mRNA type with pretreatment hematologic characteristics but not treatment outcome in acute promyelocytic leukemia: an intergroup molecular study

In each case of acute promyelocytic leukemia (APL) one of three PML-RAR alpha mRNA types is produced, depending on the break/fusion site in the PML gene that is linked to a common RAR alpha gene segment: a short (S)-form type, PML exon 3 RAR alpha exon 3; a long (L)-form type, PML exon 6 RAR alpha exon 3; or a variable (V)-form type, variably deleted PML exon 6 RAR alpha exon 3. We evaluated whether PML-RAR alpha mRNA type is associated with distinct pretreatment clinical characteristics and therapeutic outcome in previously untreated adult APL patients registered to protocol INT 0129 by the Eastern Cooperative Oncology Group, the Southwest Oncology Group, and the Cancer and Leukemia Group B. Of 279 clinically eligible cases, 230 were molecularly evaluable, and of these, 111 were randomized to receive remission induction therapy with all-trans retinoic acid (ATRA) and 119 with conventional chemotherapy. Nine cases not excluded by central pathology review were PML-RAR alpha negative, and notably, none of five of these cases treated with ATRA achieved complete remission (CR). Among 221 PML-RAR alpha-positive cases, there were 82 S-form cases (37%), 121 L-form cases (55%), and 18 V-form cases (8%). Before any antileukemic therapy, the S-form type, compared with the L-form type, was associated with higher values for the white blood cell (WBC) count (median 2,500/microL v 1,600/microL; P = .009), the percentage of blood blasts plus promyelocytes (median 29% v 8.5%; P = .03), and the absolute blood blasts plus promyelocytes (884/microL v 126/microL; P = .019). Also, an increased percentage of S-form versus L-form cases had the M3 variant phenotype, 24% v 12% (P = .036). There were no differences between S-form and L-form cases in either CR rate (79% v 69%; P = .14) or disease free survival distribution (multivariate analysis adjusting for the association of S-form type and higher WBC count; P = .40). We conclude that the S-form type is associated with previously-identified adverse risk WBC parameters but that the identification of the S-form or L-form type of PML-RAR alpha mRNA, per se, does not predict clinical outcome or add to the value of an increased WBC count as a negative prognostic indicator in APL patients.

Usefulness of the dissecting microscope in the surgical management of skin cancers

Dermatopathological examination of excised skin cancers serves the dual purposes of defining the nature of the malignancies and evaluating the resection margins for evidence of tumor involvement. Conventional histological techniques, including horizontal frozen sections as prescribed in Mohs micrographic surgery to evaluate resection margins, can often be tedious and not without many pitfalls. In this study, the use of a stereoscopic dissecting microscope is compared with routine microscopy in the examination of 54 skin specimens resected with the clinical diagnosis of cancer. Our results show that the dissecting microscope is more efficient and as accurate in diagnosing basal and squamous cell carcinomas, and in detecting tumor involvement of resection margins. The ability to visualize marginal surfaces in three dimensions allows for a thorough examination and quick localization and mapping of the involved sites. Tissue artifacts due to fixation, freezing, or sectioning are nonexistent. With the lower cost and ease of operation, we suggest that the dissecting microscope is a more superior instrument. Its usefulness in the surgical management of skin cancers should be emphasized and further validated.