Search

This study revisited the Dohner prognostic hierarchy in a cohort of 1585 well-documented patients with chronic lymphocytic leukaemia. The duration of both time to first treatment (TTFT) and overall survival (OS) were significantly longer than observed previously, and this is at least partly due to improved therapeutic options. Deletion 13q remains the most favourable prognostic group with median TTFT and OS from fluorescence in situ hybridization (FISH) testing of 72 months and >12 years, respectively. Deletion 11q had the poorest median TTFT (22 months) and 17p deletion the poorest median OS (5 years). The percentages of abnormal nuclei were significantly associated with differential TTFT for the trisomy 12, 13q and 17p deletion cohorts but not for the 11q deletion cohort. From the date of the first FISH study, patients with >85% 13q deletion nuclei had a notably shorter TTFT (24 months). Patients with ≤20% 17p deletion nuclei had longer median TTFT and OS from the date of the first FISH study (44 months and 11 years), and were more likely to be IGHV mutated.

The accurate identification and description of chromosomal abnormalities observed by conventional G-banded chromosome studies in hematologic neoplasms is critical for patient management, including diagnosis, prognosis, disease classification, and/or therapy-related decisions. [...], * Context.--One goal of the joint College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee is to ensure the accurate detection and description of chromosomal abnormalities in both constitutional and neoplastic specimens, including hematologic neoplasms. Objective.--To report a 20-year performance summary (1999-2018) of conventional chromosome challenges focusing on hematologic neoplasms. Design.--A retrospective review was performed from 1999 through 2018 to identify karyotype challenges specifically addressing hematologic neoplasms. The overall performance of participants was examined to identify potential recurring errors of clinical significance. Results.--Of 288 total conventional chromosome challenges from 1999-2018, 87 (30.2%) were presented in the context of a hematologic neoplasm, based on the provided clinical history, specimen type, and/or chromosomal abnormalities. For these 87 hematologic neoplasm challenges, 91 individual cases were provided and graded on the basis of abnormality recognition and karyotype nomenclature (ISCN, International System for Human Cytogenomic [previously Cytogenetic] Nomenclature). Of the 91 cases, 89 (97.8%) and 87 (95.6%) exceeded the required 80% consensus for grading of abnormality recognition and correct karyotype nomenclature, respectively. The 2 cases (2 of 91; 2.2%) that failed to meet the 80% consensus for abnormality recognition had complex karyotypes. The 4 cases (4 of 91; 4.4%) that failed to meet the 80% consensus for correct karyotype nomenclature were the result of incorrect abnormality recognition (2 cases), missing brackets in the karyotype (1 case), and incorrect breakpoint designation (1 case). Conclusions.--This 20-year review demonstrates clinical cytogenetics laboratories have been and continue to be highly proficient in the detection and description of chromosomal abnormalities associated with hematologic neoplasms. doi: 10.5858/arpa.2020-0089-CP

Simple Summary: Chronic lymphocytic leukemia (CLL) is a cancer of the blood and bone marrow, commonly affecting older adults. Most CLL patients have an abnormal copy number of chromosomes that are used for risk stratification. Chromosomal copy number changes have been evaluated using a technique called Fluorescence in situ hybridization (FISH). Next-generation sequencing (NGS) is now common practice in many cancers and in addition to DNA mutations, can also identify genetic copy number alterations. Together, these could inform disease prognosis and guide decisions on treatment. This study evaluated NGS as an alternative method to FISH for detecting clinically relevant chromosomal copy number changes in CLL. Chronic lymphocytic leukemia (CLL) is characterized by multiple copy number alterations (CNAs) and somatic mutations that are central to disease prognosis, risk stratification, and mechanisms of therapy resistance. Fluorescence in situ hybridization (FISH) panels are widely used in clinical applications as the gold standard for screening prognostic chromosomal abnormalities in CLL. DNA sequencing is an alternative approach to identifying CNAs but is not an established method for clinical CNA screening. We sequenced DNA from 509 individuals with CLL or monoclonal B-cell lymphocytosis (MBL), the precursor to CLL, using a targeted sequencing panel of 59 recurrently mutated genes in CLL and additional amplicons across regions affected by clinically relevant CNAs [i.e., del(17p), del(11q), del(13q), and trisomy 12]. We used the PatternCNV algorithm to call CNA and compared the concordance of calling clinically relevant CNAs by targeted sequencing to that of FISH. We found a high accuracy of calling CNAs via sequencing compared to FISH. With FISH as the gold standard, the specificity of targeted sequencing was >95%, sensitivity was >86%, positive predictive value was >90%, and negative predictive value was >84% across the clinically relevant CNAs. Using targeted sequencing, we were also able to identify other common CLL-associated CNAs, including del(6q), del(14q), and gain 8q, as well as complex karyotype, defined as the presence of 3 or more chromosomal abnormalities, in 26 patients. In a single and cost-effective assay that can be performed on stored DNA samples, targeted sequencing can simultaneously detect CNAs, somatic mutations, and complex karyotypes, which are all important prognostic features in CLL. [ABSTRACT FROM AUTHOR]

Conventional chromosome analysis plays an important role in establishing the diagnosis, prognosis, and treatment planning for hematologic malignancies, in determining the genetic basis of pregnancy loss, and other purposes. However, [...], * Context.--Chromosome analysis on bone marrow or peripheral blood samples fails in a small proportion of attempts. A method that is more reliable, with similar or better resolution, would be a welcome addition to the armamentarium of the cytogenetics laboratory.Objective.--To develop a method similar to banded metaphase chromosome analysis that relies only on interphase nuclei.Design.--To label multiple targets in an equidistant fashion along the entire length of each chromosome, including landmark subtelomere and centromere regions. Each label so generated by using cloned bacterial artificial chromosome probes is molecularly distinct with unique spectral characteristics, so the number and position of the labels can be tracked to identify chromosome abnormalities.Results.--Interphase chromosome profiling (ICP) demonstrated results similar to conventional chromosome analysis and fluorescence in situ hybridization in 55 previously studied cases and obtained useful ICP chromosome analysis results on another 29 cases in which conventional methods failed.Conclusions.--ICP is a new and powerful method to karyotype peripheral blood and bone marrow aspirate preparations without reliance on metaphase chromosome preparations. It will be of particular value for cases with a failed conventional analysis or when a fast turnaround time is required.(Arch Pathol Lab Med. 2018;142:213-228; doi: 10.5858/arpa.2016-0621-OA)

Background: Late Onset Alzheimer's Disease (LOAD) is the most common neurodegenerative disorder. Carriers of an ɛ4 allele of the apolipoprotein E gene (APOE) have significantly increased risk of developing LOAD. LOAD is also strongly sex biased. Besides the well‐established role of sex hormones, the impact of genetic sex combined with APOE genotypes has not been studied. Sex chromosome dosage (SCD) is the main genetic difference between females (XX) and males (XY). Despite dosage compensation by X chromosome inactivation (XCI), some X‐linked genes remain expressed from the inactive X (Xi) and are female biased in expression. Many of these genes are related to neurological and immune functions and could contribute to neuroinflammation in AD. Method: To understand the genetic interactions between autosomal risk (APOE) and sex‐bias in AD, we are generating isogenic sets of hiPSCs with various sex chromosome complements and APOE genotypes. We have derived XXY/XY, XY/X, and XX/X isogenic pairs by reprogramming cells from naturally mosaic individuals or by selective removal of the Xi in vitro. These lines uniquely position us to differentiate the effects of X chromosome dosage and/or presence of a Y chromosome, while minimizing genetic variability and environmental or hormonal confounders. Currently, we are also constructing APOE ɛ3 and ɛ4 alleles in our paired hiPSC lines with differing sex chromosome content using gene editing. Result: Starting from an XXY/XY isogenic pair, we have generated an hiPSC series with six different genotypes of APOE ɛ3/ɛ3, ɛ3/ɛ4 or ɛ4/ɛ4 alleles with either the XXY or XY genotype. Preliminary results in differentiated neural precursor cells show differential expression of sex‐linked genes in relation to SCD. We also observed genome‐wide changes in gene expression and DNA methylation. Subsets of autosomal sex‐biased genes were differentially affected either by X chromosome dosage, presence of a Y, or both. Conclusion: The new hiPSC lines are being differentiated to AD‐relevant cell types, including neurons, microglia, and cortical organoids, for transcriptomic and functional analyses to elucidate how APOE alleles and genetic sex interact to modulate risk in LOAD pathology. [ABSTRACT FROM AUTHOR]