Persistent genomic instability in peripheral blood lymphocytes from Hodgkin lymphoma survivors

Cytogenomic characterization of small supernumerary marker chromosomes in patients with pigmentary mosaicism

Introduction

The combination of gene content on the marker chromosome, chromosomal origin, level of mosaicism, origin mechanism (chromothripsis), and uniparental disomy can influence the final characterization of sSMCs. Several chromosomal aberrations, including sSMCs, have been observed in 30%-60% of patients with pigmentary mosaicism, and in more than 80%, chromosomal abnormalities are present in the mosaic state. In patients with pigmentary mosaicism the most representative chromosomes involved in sSMCs are 3, 5, 6, 9, 10, 13, 15, 18, 20, and X. In this study, we included the complete clinical, cytogenetic, and molecular characterization of seven patients with pigmentary mosaicism associated with the presence of SMCs of different chromosomal origins.

Methods

The patients were diagnosed by the Genetics and Dermatology Department of three different hospitals. Cytogenetic and FISH analyses were performed on peripheral blood, light skin, and dark skin. FISH analysis was performed using different probes, depending on the marker chromosome description. Different array analysis was performed.

Results

To date, of the seven cases studied, the chromosomal origins of six were successfully identified by FISH or array analysis. The chromosomes involved in SMCs were 6, 9, 15, and 18, X. The most frequently found was the centric minute structure.

Discussion

To date, this group of seven patients constitutes the largest clinical and cytogenetically finely described study of cases with pigmentary mosaicism associated with sSMCs. Undoubtedly, analysis of the two skin types is a fundamental part of our study, as numerical differences may occur in the cell lines found in each skin type. The knowledge generated in this study will help delineate a very heterogeneous entity more accurately, and in the future, analyzing more patients with PM will likely establish a more definite association with the presence of this genetic alteration.

Characterizing Chemotherapy/Radiotherapy-Induced Genome Chaos in Hodgkin's Lymphoma Patients Using M-FISH

Hodgkin lymphoma (HL) is one of the most common lymphomas, with an incidence of 3 per 100,000 persons. Current treatment uses a cocktail of genotoxic agents, including adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD), along with or without radiotherapy. This treatment regimen has proved to be efficient in killing cancer cells, resulting in HL patients having a survival rate of >90% cancer-free survival at five years. However, this therapy does not have a specific cell target, and it can induce damage in the genome of non-cancerous cells. Previous studies have shown that HL survivors often exhibit karyotypes characterized by complex chromosomal abnormalities that are difficult to analyze by conventional banding. Multicolor fluorescence in situ hybridization (M-FISH) is a powerful tool to analyze complex karyotypes; we used M-FISH to investigate the presence of chromosomal damage in peripheral blood lymphocytes from five healthy individuals and five HL patients before, during, and one year after anti-cancer treatment. Our results show that this anti-cancer treatment-induced genomic chaos that persists in the hematopoietic stem cells from HL patients one year after finishing therapy. This chromosomal instability may play a role in the occurrence of second primary cancers that are observed in 10% of HL survivors. This chapter will describe a protocol for utilizing M-FISH to study treatment-induced genome chaos in Hodgkin's lymphoma (HL) patients, following a brief discussion.

Involvement of classic and alternative non-homologous end joining pathways in hematologic malignancies: targeting strategies for treatment

Chromosomal translocations are the main etiological factor of hematologic malignancies. These translocations are generally the consequence of aberrant DNA double-strand break (DSB) repair. DSBs arise either exogenously or endogenously in cells and are repaired by major pathways, including non-homologous end-joining (NHEJ), homologous recombination (HR), and other minor pathways such as alternative end-joining (A-EJ). Therefore, defective NHEJ, HR, or A-EJ pathways force hematopoietic cells toward tumorigenesis. As some components of these repair pathways are overactivated in various tumor entities, targeting these pathways in cancer cells can sensitize them, especially resistant clones, to radiation or chemotherapy agents. However, targeted therapy-based studies are currently underway in this area, and furtherly there are some biological pitfalls, clinical issues, and limitations related to these targeted therapies, which need to be considered. This review aimed to investigate the alteration of DNA repair elements of C-NHEJ and A-EJ in hematologic malignancies and evaluate the potential targeted therapies against these pathways.

The Role of Microbiota in the Development of Cancer Tumour Cells and Lymphoma of B and T Cells

Human body harbours enormous numbers of microbial organisms, including bacteria, viruses, and fungi which have a momentous role in well-being and illness in humans. Immune system shelters us from pathogenic bacteria, microorganisms found in human tissues have many benefits related to the functional movement of the host by regulating important procedures such as immunity, signalling, and breakdown. Lymphocytes assume a significant part in the reaction to bacterial colonization, primarily by prompting a safe reaction to obstruction or initiation. Most immunologically occupant cells have a place with the mucosal invulnerable framework and are continually motioned by dendritic cells or other Antigen introducing cells that gather intestinal samples. Thus, Microbiome is a key contributor to developing lymphoma and specific alterations to microbiome composition could attenuate the risk. There is an indication that microbial morphology can affect and control humanoids. The difference in the composition of these microorganisms is associated with tumour development. With the increased knowledge of the connection among the human microbiome and carcinogenesis, the use of these findings to prevent, predict or diagnose of lymphomas has attracted a great attention. In this article, we explored current knowledge of various microbial ecosystems, their connection with carcinogens and the potential for useful microorganisms to control and prevent B and T cell lymphoma.

Gut Microbiota Influence in Hematological Malignancies: From Genesis to Cure

Hematological malignancies, including multiple myeloma, lymphoma, and leukemia, are a heterogeneous group of neoplasms that affect the blood, bone marrow, and lymph nodes. They originate from uncontrolled growth of hematopoietic and lymphoid cells from different stages in their maturation/differentiation and account for 6.5% of all cancers around the world. During the last decade, it has been proven that the gut microbiota, more specifically the gastrointestinal commensal bacteria, is implicated in the genesis and progression of many diseases. The immune-modulating effects of the human microbiota extend well beyond the gut, mostly through the small molecules they produce. This review aims to summarize the current knowledge of the role of the microbiota in modulating the immune system, its role in hematological malignancies, and its influence on different therapies for these diseases, including autologous and allogeneic stem cell transplantation, chemotherapy, and chimeric antigen receptor T cells.

Meiotic susceptibility for induction of sperm with chromosomal aberrations in patients receiving combination chemotherapy for Hodgkin lymphoma

Improvements in survival rates with gonad-sparing protocols for childhood and adolescence cancer have increased the optimism of survivors to become parents after treatment. Findings in rodents indicate that chromosomal aberrations can be induced in male germ cells by genotoxic exposures and transmitted to offspring and future generations with effects on development, fertility and health. Thus, there is a need for effective technologies to identify human sperm carrying chromosomal aberrations to assess the germ-line risks, especially for cancer survivors who have received genotoxic therapies. The time-dependent changes in the burden of sperm carrying structural chromosomal aberrations were assessed for the first time in a cancer setting, using the AM8 sperm FISH protocol which simultaneously detects abnormalities in chromosomal structure and number in sperm. Nine Hodgkin lymphoma (HL) patients provided 20 semen samples before, during, and after NOVP therapy (Novantrone, Oncovin, Velban and Prednisone) and radiation therapy that produced scattered gonadal doses from <0.05 to 0.6 Gy. Late meiosis was found to be the most sensitive to NOVP treatment for the production of sperm with chromosomal abnormalities, both in structure and number. Earlier stages of spermatogenesis were less sensitive and there was no evidence that therapy-exposed stem cells resulted in increased frequencies of sperm with abnormalities in chromosomal structure or number. This indicates that NOVP therapy may increase the risks for paternal transmission of chromosomal structural aberrations for sperm produced 32 to 45 days after a treatment with these drugs and implies that there are no excess risks for pregnancies conceived more than 6 months after this therapy. This clinical evaluation of the AM8 sperm FISH protocol indicates that it is a promising tool for assessing an individual's burden of sperm carrying chromosomal structural aberrations as well as aneuploidies after cancer therapy, with broad applications in other clinical and environmental situations that may pose aneugenic or clastogenic risks to human spermatogenesis.

Frailty and aging in cancer survivors

There are over 15 million survivors of cancer in the United States whose rates of frailty, an aging phenotype, range from just under 10% to over 80%. Frailty impacts not only disease survival but also long-term function and quality of life in children, adolescents, and in all adults diagnosed and/or treated for cancer. This review explains frailty as a construct and model of physiologic well-being. It also describes how frailty at diagnosis impacts cancer outcomes in adult populations and enumerates the prevalence of frailty in different populations of cancer survivors. Biological mechanisms responsible for aging and potentially for frailty among individuals with or who have been treated for cancer are discussed. Finally, promising pharmaceutical and lifestyle interventions designed to impact aging rather than a specific disease, tested in other populations, but likely applicable in cancer patients and survivors, are discussed.

Nonclonal Chromosome Aberrations and Genome Chaos in Somatic and Germ Cells from Patients and Survivors of Hodgkin Lymphoma

Anticancer regimens for Hodgkin lymphoma (HL) patients include highly genotoxic drugs that have been very successful in killing tumor cells and providing a 90% disease-free survival at five years. However, some of these treatments do not have a specific cell target, damaging both cancerous and normal cells. Thus, HL survivors have a high risk of developing new primary cancers, both hematologic and solid tumors, which have been related to treatment. Several studies have shown that after treatment, HL patients and survivors present persistent chromosomal instability, including nonclonal chromosomal aberrations. The frequency and type of chromosomal abnormalities appear to depend on the type of therapy and the cell type examined. For example, MOPP chemotherapy affects hematopoietic and germ stem cells leading to long-term genotoxic effects and azoospermia, while ABVD chemotherapy affects transiently sperm cells, with most of the patients showing recovery of spermatogenesis. Both regimens have long-term effects in somatic cells, presenting nonclonal chromosomal aberrations and genomic chaos in a fraction of noncancerous cells. This is a source of karyotypic heterogeneity that could eventually generate a more stable population acquiring clonal chromosomal aberrations and leading towards the development of a new cancer.

Genomic chaos in peripheral blood lymphocytes of Hodgkin's lymphoma patients one year after ABVD chemotherapy/radiotherapy

Hodgkin's lymphoma (HL) is a lymphoid malignancy representing 5% of all cancers in children, 16% in adolescents, and 30-40% of all malignant lymphomas and has a survival rate of ~95% at 10 years. One of the most common treatment schemes uses a cocktail of genotoxic agents including adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) with or without radiotherapy. We investigated the occurrence of chromosomal damage in peripheral blood lymphocytes from five patients diagnosed with HL who provided samples before (BT), during chemotherapy (DT) and ~1 year after ABVD chemotherapy/radiotherapy (AT). Five healthy subjects served as controls. Chromosomal abnormalities were evaluated by multicolor fluorescence in situ hybridization. The average frequencies of structural chromosomal aberrations in HL samples were 0.11, 0.22, and 0.96 per cell in BT, DT, and AT samples, respectively. These frequencies were significantly different (P < 0.0001) with respect to control subjects (0.02 per cell). Interestingly, the highest frequency of structural damage, including genomic chaos and nonclonal abnormalities, was observed in the AT samples indicating that new aberrations were continuously produced. Rejoined structural chromosomal aberrations were the most common type of aberrations, although aneuploidies were also significantly increased. Finally, we found several chromosomal abnormalities linked to cancer secondary to treatment in all five HL patients. Our results show that ABVD chemotherapy plus radiotherapy is inducing genomic chaos in vivo; moreover, the persistence of genomic instability in the hematopoietic stem cells from HL patients may play a role in the occurrence of secondary cancer that is observed in 5-20% of HL patients. Environ. Mol. Mutagen. 59:755-768, 2018. © 2018 Wiley Periodicals, Inc.

Chromosomal Instability in Hodgkin Lymphoma: An In-Depth Review and Perspectives

The study of Hodgkin lymphoma (HL), with its unique microenvironment and long-term follow-up, has provided exceptional insights into several areas of tumor biology. Findings in HL have not only improved our understanding of human carcinogenesis, but have also pioneered its translation into the clinics. HL is a successful paradigm of modern treatment strategies. Nonetheless, approximately 15–20% of patients with advanced stage HL still die following relapse or progressive disease and a similar proportion of patients are over-treated, leading to treatment-related late sequelae, including solid tumors and organ dysfunction. The malignant cells in HL are characterized by a highly altered genomic landscape with a wide spectrum of genomic alterations, including somatic mutations, copy number alterations, complex chromosomal rearrangements, and aneuploidy. Here, we review the chromosomal instability mechanisms in HL, starting with the cellular origin of neoplastic cells and the mechanisms supporting HL pathogenesis, focusing particularly on the role of the microenvironment, including the influence of viruses and macrophages on the induction of chromosomal instability in HL. We discuss the emerging possibilities to exploit these aberrations as prognostic biomarkers and guides for personalized patient management.

New Insights in the Cytogenetic Practice: Karyotypic Chaos, Non-Clonal Chromosomal Alterations and Chromosomal Instability in Human Cancer and Therapy Response

Recently, non-clonal chromosomal alterations previously unappreciated are being proposed to be included in cytogenetic practice. The aim of this inclusion is to obtain a greater understanding of chromosomal instability (CIN) and tumor heterogeneity and their role in cancer evolution and therapy response. Although several genetic assays have allowed the evaluation of the variation in a population of cancer cells, these assays do not provide information at the level of individual cells, therefore limiting the information of the genomic diversity within tumors (heterogeneity). The karyotype is one of the few available cytogenetic techniques that allow us not only to identify the chromosomal alterations present within a single cell, but also allows us to profile both clonal (CCA) and non-clonal chromosomal alterations (NCCAs). A greater understanding of CIN and tumor heterogeneity in cancer could not only improve existing therapeutic regimens but could also be used as targets for the design of new therapeutic approaches. In this review we indicate the importance and significance of karyotypic chaos, NCCAs and CIN in the prognosis of human cancers.

Mechanisms and clinical applications of chromosomal instability in lymphoid malignancy

Lymphocytes are unique among cells in that they undergo programmed DNA breaks and translocations, but that special property predisposes them to chromosomal instability (CIN), a cardinal feature of neoplastic lymphoid cells that manifests as whole chromosome- or translocation-based aneuploidy. In several lymphoid malignancies translocations may be the defining or diagnostic markers of the diseases. CIN is a cornerstone of the mutational architecture supporting lymphoid neoplasia, though it is perhaps one of the least understood components of malignant transformation in terms of its molecular mechanisms. CIN is associated with prognosis and response to treatment, making it a key area for impacting treatment outcomes and predicting prognoses. Here we will review the types and mechanisms of CIN found in Hodgkin lymphoma, non-Hodgkin lymphoma, multiple myeloma and the lymphoid leukaemias, with emphasis placed on pathogenic mutations affecting DNA recombination, replication and repair; telomere function; and mitotic regulation of spindle attachment, centrosome function, and chromosomal segregation. We will discuss the means by which chromosome-level genetic aberrations may give rise to multiple pathogenic mutations required for carcinogenesis and conclude with a discussion of the clinical applications of CIN and aneuploidy to diagnosis, prognosis and therapy.

Partial and complete trisomy 14 mosaicism: clinical follow-up, cytogenetic and molecular analysis

BACKGROUND

Trisomy 14 mosaicism is a rare chromosomal abnormality. It is associated with multiple congenital anomalies. We report a 15 year-old female with an unusual karyotype with three cell lines: 47,XX,+mar/47,XX,+14/46,XX. At six months old she had short stature, cleft palate, hyperpigmented linear spots in arms and legs and developmental delay. At present, she has mild facial dysmorphism and moderate mental retardation.

METHODS

Cytogenetic analysis was performed in peripheral blood lymphocytes and in the light and dark skin following standard methods. DNAarray - Oligo 180 k was carried out using Agilent Technologies and FISH analysis was accomplished using DNA BACs probes to confirm the result obtained by DNAarray. Methylation-Specific PCR (MS-PCR) of the MEG3 promoter and microsatellite analysis were performed.

RESULTS

Microarray analysis confirmed partial trisomy 14 mosaicism; the marker chromosome was found to be from chromosome 14, the result was confirmed with FISH. Methylation (14q32.3) and microsatellite (14q11-14q32.33) analysis were carried out and UPD was discarded. The global result was: mos 47,XX,+del(14)(q11.2)[45]/47,XX,+14[10]/46,XX[45].

CONCLUSIONS

This is a unique case because of the coexistence of two abnormal cell lines, including one with +14 and another with +del(14)(q11.2). To our knowledge, only three patients have been reported with trisomy 14 and another abnormal cell line. The array analysis identified the marker chromosome and characterized the breakpoint. The del(14)(q11.2) does not seem to be related to any particular phenotypic characteristic of the patient; the clinical features of our patient observed until now, can be attributed to trisomy 14 mosaicism. Nevertheless, we cannot discard the manifestation of new symptoms related to her karyotype in the future.

Single-nucleotide polymorphism array genotyping is equivalent to metaphase cytogenetics for diagnosis of Turner syndrome

PURPOSE

Turner syndrome is a developmental disorder caused by partial or complete monosomy for the X chromosome in 1 in 2,500 females. We hypothesized that single-nucleotide polymorphism (SNP) array genotyping could provide superior resolution in comparison to metaphase karyotype analysis to facilitate genotype-phenotype correlations.

METHODS

We genotyped 187 Turner syndrome patients with 733,000 SNP marker arrays. All cases met diagnostic criteria for Turner syndrome based on karyotypes (60%) or characteristic physical features. The SNP array results confirmed the diagnosis of Turner syndrome in 100% of cases.

RESULTS

We identified a single X chromosome (45,X) in 113 cases. In 58 additional cases (31%), other mosaic cell lines were present, including isochromosomes (16%), rings (5%), and Xp deletions (8%). The remaining cases were mosaic for monosomy X and normal male or female cell lines. Array-based models of X chromosome structure were compatible with karyotypes in 104 of 116 comparable cases (90%). We found that the SNP array data did not detect X-autosome translocations (three cases) but did identify two derivative Y chromosomes and 13 large copy-number variants that were not detected by karyotyping.

CONCLUSION

Our study is the first systematic comparison between the two methods and supports the utility of SNP array genotyping to address clinical and research questions in Turner syndrome.

Fecal microbiota diversity in survivors of adolescent/young adult Hodgkin lymphoma: a study of twins

BACKGROUND

Adolescent/young adult Hodgkin lymphoma (AYAHL) survivors report fewer exposures to infections during childhood compared with controls, and they have functional lymphocyte aberrations. The gut microbiota plays a central role in immunity.

METHODS

We investigated whether fecal microbial diversity differed between 13 AYAHL survivors and their unaffected co-twin controls. Pyrosequencing of fecal bacterial 16S rRNA amplicons yielded 252 943 edited reads that were assigned to species-level operational taxonomic units (OTUs) and standardised for sequencing depth by random sampling. Microbial diversity was compared within vs between twin pairs and by case-control status.

RESULTS

The number of unique OTUs was more similar within twin pairs compared with randomly paired participants (P=0.0004). The AYAHL cases had fewer unique OTUs compared with their co-twin controls (338 vs 369, P=0.015); this difference was not significant (169 vs 183, P=0.10) when restricted to abundant OTUs.

CONCLUSION

In this small study, AYAHL survivors appear to have a deficit of rare gut microbes. Further work is needed to determine if reduced microbial diversity is a consequence of the disease, its treatment, or a particularly hygienic environment.