PARP1 V762A polymorphism affects the prognosis of myelodysplastic syndromes

Germline predisposition for clonal hematopoiesis

Clonal hematopoiesis (CH) is an entity hallmarked by skewed hematopoiesis with persistent overrepresentation of cells from a common stem/progenitor lineage harboring single-nucleotide variants and/or insertions/deletions. CH is a common and age-related phenomenon that is associated with an increased risk of hematological malignancies, cardiovascular disease, and all-cause mortality. While CH is a term of the hematological aspect, there exists a complex interaction with other organ systems, especially the cardiovascular system. The strongest factor in the development of CH is aging, however, other multiple factors also affect the development of CH including lifestyle-related factors and co-morbid diseases. In recent years, germline genetic factors have been linked to CH risk. In this review, we synthesize what is currently known about how genetic variation affects the risk of CH, how this genetic architecture intersects with myeloid neoplasms, and future prospects for CH.

Common and rare variant associations with clonal haematopoiesis phenotypes

Clonal haematopoiesis involves the expansion of certain blood cell lineages and has been associated with ageing and adverse health outcomes^1-5. Here we use exome sequence data on 628,388 individuals to identify 40,208 carriers of clonal haematopoiesis of indeterminate potential (CHIP). Using genome-wide and exome-wide association analyses, we identify 24 loci (21 of which are novel) where germline genetic variation influences predisposition to CHIP, including missense variants in the lymphocytic antigen coding gene LY75, which are associated with reduced incidence of CHIP. We also identify novel rare variant associations with clonal haematopoiesis and telomere length. Analysis of 5,041 health traits from the UK Biobank (UKB) found relationships between CHIP and severe COVID-19 outcomes, cardiovascular disease, haematologic traits, malignancy, smoking, obesity, infection and all-cause mortality. Longitudinal and Mendelian randomization analyses revealed that CHIP is associated with solid cancers, including non-melanoma skin cancer and lung cancer, and that CHIP linked to DNMT3A is associated with the subsequent development of myeloid but not lymphoid leukaemias. Additionally, contrary to previous findings from the initial 50,000 UKB exomes⁶, our results in the full sample do not support a role for IL-6 inhibition in reducing the risk of cardiovascular disease among CHIP carriers. Our findings demonstrate that CHIP represents a complex set of heterogeneous phenotypes with shared and unique germline genetic causes and varied clinical implications.

DNA Damage Response in Multiple Myeloma: The Role of the Tumor Microenvironment

Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by genomic instability. MM cells present various forms of genetic instability, including chromosomal instability, microsatellite instability, and base-pair alterations, as well as changes in chromosome number. The tumor microenvironment and an abnormal DNA repair function affect genetic instability in this disease. In addition, states of the tumor microenvironment itself, such as inflammation and hypoxia, influence the DNA damage response, which includes DNA repair mechanisms, cell cycle checkpoints, and apoptotic pathways. Unrepaired DNA damage in tumor cells has been shown to exacerbate genomic instability and aberrant features that enable MM progression and drug resistance. This review provides an overview of the DNA repair pathways, with a special focus on their function in MM, and discusses the role of the tumor microenvironment in governing DNA repair mechanisms.