Novel next-generation sequencing-based methodologies to characterize the mutational consequences of (prenatal) chemotherapy exposure in noncancerous tissue.

PURPOSE OF REVIEW: Although chemotherapeutics are considered as genotoxins for decades, their exact mutagenic impact on the genome of cancerous and normal cells of cancer patients was unknown for a long time. However, this knowledge is necessary to understand the long-term side effects of chemotherapy. A particular condition represents pregnant cancer patients being treated with chemotherapy. Since certain chemotherapeutics can cross the placenta, concerns exist about possible mutational effects on the fetus' genome with potential long-term health consequences. RECENT FINDINGS: Recent advances of next-generation sequencing (NGS) techniques have opened possibilities to explore the exact mutational footprint of chemotherapies in healthy tissue from treated cancer patients. However, the ultra-low frequency of chemotherapy-induced mutations, introduction of technical artefacts, and inaccessibility of normal tissue has posed important limitations. This review discusses five state-of-the-art approaches that were recently designed to overcome these drawbacks. SUMMARY: Results of the latest investigations give valuable insights into the genome-wide genotoxicity profile of frequently applied chemotherapies, with most of these drugs being associated with a signature of random base substitutions and small indels. Though these findings still might be limited to extrapolate to healthy tissue, they pave the way for studies on the origin of long-term chemotherapy-related adverse health effects.

Evaluating offspring Genomic and Epigenomic alterations after prenatal exposure to Cancer treatment In Pregnancy (GE-CIP): a multicentric observational study.

INTRODUCTION: Around 1 in 1000-2000 pregnancies are affected by a cancer diagnosis. Previous studies have shown that chemotherapy during pregnancy has reassuring cognitive and cardiac neonatal outcomes, and hence has been proposed as standard of care. However, although these children perform within normal ranges for their age, subtle differences have been identified. Given that chemotherapeutic compounds can cross the placenta, the possibility that prenatal chemotherapy exposure mutates the offspring's genome and/or epigenome, with potential deleterious effects later in life, urges to be investigated. METHODS AND ANALYSES: This multicentric observational study aims to collect cord blood, meconium and neonatal buccal cells at birth, as well as peripheral blood, buccal cells and urine from infants when 6, 18 and/or 36 months of age. Using bulk and single-cell approaches, we will compare samples from chemotherapy-treated pregnant patients with cancer, pregnant patients with cancer not treated with chemotherapy and healthy pregnant women. Potential chemotherapy-related newborn genomic and/or epigenomic alterations, such as single nucleotide variants, copy number variants and DNA-methylation alterations, will be identified in mononuclear and epithelial cells, isolated from blood, buccal swabs and urine. DNA from maternal peripheral blood and paternal buccal cells will be used to determine de novo somatic mutations in the neonatal blood and epithelial cells. Additionally, the accumulated exposure of the fetus, and biological effective dose of alkylating agents, will be assessed in meconium and cord blood via mass spectrometry approaches. ETHICS AND DISSEMINATION: The Ethics Committee Research of UZ/KU Leuven (EC Research) and the Medical Ethical Review Committee of University Medical Center Amsterdam have approved the study. Results of this study will be disseminated via presentations at (inter)national conferences, through peer-reviewed, open-access publications, via social media platforms aimed to inform patients and healthcare workers, and through the website of the International Network on Cancer, Infertility and Pregnancy (www.cancerinpregnancy.org).

Characterization of the genotoxic profile of antineoplastic drugs using the cytokinesis-block micronucleus cytome assay.

Since antineoplastic agents are frequently used in cancer therapy and able to affect the patient's DNA, it is important to know the genotoxic consequences on non-cancerous tissue. Therefore, we aimed to characterize the genotoxic profile of antineoplastic drugs belonging to different classes, using the cytokinesis-block micronucleus cytome assay in a human monocytic cell line (THP-1). All tested antineoplastic agents resulted in increased micronucleus formation. Exposure to anthracyclines led to an increased number of vacuolated cells and cell death, while for mitotic spindle inhibitors, (different stages of) cell death and an increased nuclear bud formation was observed. Alkylating agents induce a high proportion of vacuolated cells and increased nuclear bud formation. No striking differences of nuclear division index or nucleoplasmic bridge formation were observed between exposed and non-exposed cells. The here presented class-specific aberrations may facilitate interpretation of genotoxic aberrations when evaluating clinical samples from patients treated with these antineoplastic agents.

Association of Chemotherapy Timing in Pregnancy With Congenital Malformation.

Importance: Chemotherapy during the first trimester of pregnancy should be avoided owing to the risk of congenital malformations. However, the precise gestational age at which chemotherapy can be initiated safely remains unclear. Objective: To assess congenital malformation rates associated with gestational age at initiation of chemotherapy among pregnant women with cancer. Design, Setting, and Participants: This multicenter cohort study evaluated all pregnant women who received chemotherapy between 1977 and 2019 registered in the International Network on Cancer, Infertility and Pregnancy (INCIP) database. Data were analyzed from February 15 to June 2, 2020. Exposures: Cancer treatment with chemotherapy during pregnancy. Main Outcomes and Measures: Analysis was focused on major and minor structural malformations in offspring, defined by EUROCAT, detected during pregnancy or at birth. Results: A total of 755 women in the INCIP database who underwent cancer treatment with chemotherapy during pregnancy were included in analysis. The median (range) age at cancer diagnosis was 33 (14-48) years. Among offspring, the major congenital malformation rate was 3.6% (95% CI, 2.4%-5.2%), and the minor congenital malformation rate was 1.9% (95% CI, 1.0%-3.1%). Chemotherapy exposure prior to 12 weeks gestational age was associated with a high rate of major congenital malformations, at 21.7% (95% CI, 7.5%-43.7%; odds ratio, 9.24 [95% CI, 3.13-27.30]). When chemotherapy was initiated after gestational age 12 weeks, the frequency of major congenital malformations was 3.0% (95% CI, 1.9%-4.6%), which was similar to the expected rates in the general population. Minor malformations were comparable when exposure occurred before or after gestational age 12 weeks (4.3% [95% CI, 0.1%-21.9%] vs 1.8% [95% CI, 1.0-3.0]; odds ratio, 3.13 [95% CI, 0.39-25.28]). Of 29 women who received chemotherapy prior to 12 weeks gestation, 17 (58.6%) were not aware of pregnancy, and 6 (20.7%) experienced a miscarriage (3 women [10.3%]) or decided to terminate their pregnancy (3 women [10.3%]). Conclusions and Relevance: This cohort study found that chemotherapy was associated with an increased risk of major congenital malformations only in the first 12 weeks of pregnancy. The risk of congenital malformations when chemotherapy was administered during the first trimester and the high number of incidental pregnancies during cancer treatment in the INCIP registry underscore the importance of contraceptive advice and pregnancy testing at the start of chemotherapeutic treatment in young women with cancer.