Clinical significance of acquired loss of the X chromosome in bone marrow

Cytogenetics in the management of clonal chromosomal abnormalities of undetermined significance and persistent polyclonal B-cell lymphocytosis: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Acquired clonal chromosomal abnormalities (CAs) are usually considered to be disease-related. However, when a CA of this type is the only abnormality present (and especially in small clones), the clinical significance is unclear. Here, we review the literature on recurrent CAs whose significance is regularly subject to debate. Our objective was to help with their interpretation and develop guidelines for sex chromosome loss, trisomy 15, trisomy 8, deletion 20q and other isolated non-myelodysplastic neoplasm (MDS)-defining CAs. We suggest that non-MDS-defining CAs correspond to clonal hematopoiesis of indeterminate potential (CHIP) in the absence of cytopenia and clonal cytopenia of undetermined significance (CCUS) in the presence of cytopenia. Lastly, we review the literature on persistent polyclonal binucleated B-cell lymphocytosis; although usually benign, this condition may correspond to a premalignant state.

Myelodysplastic Syndromes: Laboratory Workup in the Context of New Concepts and Classification Criteria

PURPOSE OF REVIEW

This review provides a comprehensive update of myelodysplastic syndromes (MDS) and their diagnostic criteria, with emphasis on novel concepts and state-of-the-art laboratory workup, including multiparameter/multicolor flow cytometry, chromosome analysis, and mutation profiling.

RECENT FINDINGS

Recent advances in genetics and molecular technologies have provided unprecedented insights into the pathogenic mechanisms and genomic landscape of MDS and its precursor lesions. This has resulted in revised diagnostic criteria in the World Health Organization (WHO) classification and proposed new terminology for early lesions such as clonal hematopoiesis of indeterminate potential (CHIP). Against this landscape, a thorough understanding of the advantages and limitations of laboratory tests employed in the evaluation of patients with cytopenia has gained unprecedented importance. Healthcare providers involved in the care of patients with hematologic diseases should be aware of the intricacies of laboratory workup of such patients, particularly in view of the novel concepts and classification criteria of MDS.

Loss of whole chromosome X predicts prognosis of neuroblastoma patients with numerical genomic profile

BACKGROUND

Neuroblastoma (NB), a pediatric tumor of the sympathetic nervous system, is characterized by very frequent chromosomal aberrations at the onset of the disease. Identification of further risk factors for relapse, which could lead to increased survival and potentially reduced late effects among survivors, is still urgently needed. Segmental chromosome aberrations (SCA) are associated with poor prognosis, whereas numerical whole-chromosome aberrations (NCA) are found in patients with a good prognosis; however, a small percentage of the latter patients (10%-15%) subsequently relapse and/or die of disease.

PROCEDURE

DNA copy-number data from 174 NB patients with an NCA genomic profile were analyzed. Association between NCA and event-free survival (EFS) was investigated by the Kaplan-Meier estimator and prognostic decision tree (DT).

RESULTS

DT identified 65 patients with normal chromosome X and an excellent five-year EFS (100%) independently from the stage at diagnosis. The association between poor EFS and whole chromosome X alterations was confirmed after stratification into two groups of different expected prognosis and by internal validation via bootstrap analysis. Furthermore, the association was also observed in an independent cohort of NB patients extracted from the data set of the National Cancer Institute TARGET Project for Neuroblastoma, but sample size was small (n = 75) and statistical significance was not achieved.

CONCLUSIONS

Loss of whole chromosome X may represent a new prognostic marker for NB patients with an NCA genomic profile. If confirmed by further studies, this finding could indicate that such patients should be reclassified as intermediate risk and treated accordingly.

Ring sideroblasts in chronic phase of polycythemia vera identifies a subset of patients with an increased risk of progression to blast phase

Blast phase of PV is often associated with a complex karyotype (CK) and bilineage dysplasia. We hypothesized that BM morphologic abnormalities detected in the Chronic phase (CP) can identify patients with an increased risk of developing blast phase (BP). We also compared cases of BP PV to a group of acute myeloid leukemia cases with JAK2 mutation (AML-JAK2mut). We collected morphological, cytogenetics (CG), and molecular information at the time of diagnosis and at time of diagnosis of BP. We evaluate the presence of splicing factor mutations at BP. A total of 60/477 (12.5%) patients with diagnosis of BP of PV were identified, 17 of them had BM sample available during CP. Ten patients with PV CP were used as control group. We found that dyserythropoiesis during evolution were more frequent in patients who develop BP than in patients who remain in CP (13/17 vs. 3/10; P = .0402). Similarly, ring sideroblast (RS) increase during CP were more frequent in patients who develop BP (8/16 vs. 0/10. P = .0095). By ELN risk stratification for CG risk in BP all patients had adverse or intermediate risk; in AML-JAK2mut 2/11 patients (18%) had favorable as risk category. TP53 mutations were significantly more frequent in BP than in AML-JAK2mut (7/14 vs. 1/11, P = .0421). Mutation analysis for splicing factor at BP was performed on 13 patients. Only 2 patients with >15% RS had SRSF2 (2 patients) and SF3B1 (1 patient) mutations. The other patients were wild type. Dyserythropoiesis and the acquisition of RS precede other markers of disease progression to BP. CK and TP53 mutation are more frequent in BP than in AML-JAK2mut. SF3B1 mutations are rare in BP.

Bone marrow core biopsy in 508 consecutive patients with chronic myeloid leukemia: Assessment of potential value

BACKGROUND

The diagnosis of chronic myeloid leukemia (CML) is based on characteristic clinical and laboratory findings and the presence of BCR/ABL1 in the blood and/or bone marrow (BM). The utility of BM core biopsy in the workup of patients with CML has been questioned.

METHODS

The potential added value of BM biopsy versus aspiration in the workup of a single-institution series of 508 patients with CML at their initial presentation was systematically assessed. BM biopsy was considered essential when it was needed to establish the disease phase, often because blast counts derived from aspirate smears were misleading because the biopsy specimen was more representative of the disease. BM biopsy was considered helpful if it was needed for other nonessential reasons.

RESULTS

In 127 patients (25%), BM biopsy was either essential (109 patients) or helpful (18 patients). Patients with accelerated-phase (AP) or blast-phase (BP) disease often required a biopsy related to essential reasons. High-grade myelofibrosis (MF) was more frequent in patients with AP/BP disease than patients with chronic-phase disease (P = .0005), and the identification of BP disease required a BM biopsy assessment in 75% of the patients (P = .001). A follow-up BM evaluation more often yielded inadequate aspirates in patients with inadequate BM aspirates at the time of their initial diagnosis.

CONCLUSIONS

BM core biopsy remains valuable in the workup of 25% of patients with CML because it facilitates identification of the disease phase or MF. The initial grade of MF is associated with the disease stage and outcome after therapy. BM biopsy is, therefore, indicated for patients with CML who have AP/BP disease or other findings suggestive of progressive disease.

How I investigate Clonal cytogenetic abnormalities of undetermined significance

Myelodysplastic syndromes are a group of hematopoietic stem cell diseases characterized by cytopenia(s), morphological dysplasia, and clonal hematopoiesis. In some patients, the cause of cytopenia(s) is uncertain, even after thorough clinical and laboratory evaluation. Evidence of clonal hematopoiesis has been used to support a diagnosis of myelodysplastic syndrome in this setting. In patients with cytopenia(s), the presence of clonal cytogenetic abnormalities, except for +8, del(20q) and -Y, can serve as presumptive evidence of myelodysplastic syndrome. Recent advances in next-generation sequencing have detected myeloid neoplasm-related mutations in patients who do not meet the diagnostic criteria for myelodysplastic syndrome. Various terms have been adopted to describe these cases, including clonal hematopoiesis of indeterminate potential (CHIP) and clonal cytopenia of undetermined significance (CCUS). Similarly, studies have shown that certain chromosomal abnormalities, including ones commonly detected in myelodysplastic syndrome, may not be associated necessarily with an underlying myelodysplastic syndrome. These clonal cytogenetic abnormalities of undetermined significance (CCAUS) are similar to CHIP and CCUS. Here, we review the features of CCAUS, distinguishing CCAUS from clonal cytogenetic abnormalities associated with myelodysplastic syndrome, and the potential impact of CCAUS on patient management.

Sex chromosome loss after allogeneic hematopoietic stem cell transplant in patients with hematologic neoplasms: a diagnostic dilemma for clinical cytogeneticists

BACKGROUND

Sex chromosome loss (SCL), including loss of an X chromosome (-X) in females and loss of the Y chromosome (-Y) in males, resulting in a karyotype of 45,X, rarely occurs in patients post an allogeneic hematopoietic stem cell transplant (alloHSCT). However, origin of this abnormal clone and its clinical significance remains unknown.

RESULTS

We present 12 cases with SCL who underwent alloHSCT; 9 patients (4 men and 5 women with a median age of 56 years) developed isolated SCL after alloHSCT (Group I), and 3 patients (all women with a median age of 58 years) had a SCL before undergoing alloHSCT after which SCL disappeared (Group II). The primary neoplasms included chronic lymphocytic leukemia (n = 5), acute myeloid leukemia (n = 5), chronic myelogenous leukemia with nodal marginal zone lymphoma (n = 1) and Hodgkin lymphoma (n = 1). According to the donor/recipient relationship, their alloHSCT can be divided into sex-matched, HLA-matched, unrelated donors (n = 2); sex-mismatched, HLA-matched, unrelated donors (n = 4); sex-mismatched, HLA-matched, related donors (2 HLA-identical and 2 HLA-haploidentical cases) and sex-matched, HLA-matched, related donors (2 HLA-haploidentical cases). In Group I, isolated SCL was first detected with a median interval of 3 months (range 1 to 42 months) after the alloHSCT. By the end of clinical follow-up in patients in Group I, 7 patients expired with a median overall survival of 45 months (range 3 to 108 months) after alloHSCT and 33 months (range 0 to 66 months) after SCL detection. In Group II, 1 patient expired with a survival time of 54 months after the alloHSCT. Detection of SCL after alloHSCT can be transient, intermittent or persistent.

CONCLUSIONS

Interpretation of SCL is challenging in the context of alloHSCT. Chimerism testing is useful in determining the origin of SCL. In the case of SCL with donor/recipient chimerism, deduction of the SCL origin by all means and use of "-?X" or "-?Y" in the ISCN nomenclature are recommended. Clinical follow-up with closely monitoring the SCL by both cytogenetic and molecular analyses is needed.