Molecular determinants of juvenile myelomonosytic leukemia and childhood myelodysplastic syndrome

In the general population the probability of developing cancer before the age of 18 years is around 1 in 400. In the Netherlands, approximately 600 new children each year are diagnosed with cancer (Figure 1). The most common types of childhood cancer are leukemias and the distribution of cancer types varies with age. Figure 2 gives an overview of the incidence of the different subclasses of leukemia as registered by the DCOG (2005-2010). Acute lymphoblastic leukemia (ALL) accounts for about 80% of the leukemias, whereas acute myeloid leukemia (AML) accounts for about 15% of all leukemias. Myelodysplastic syndrome (MDS) and Juvenile Myelomonocytic Leukemia (JMML), which are the subject of this thesis, represent very rare myeloid malignancies in childhood. Over the last decades, following better treatment stratification, better chemotherapy combinations and improved supportive care regimens, the 5-year survival of cancer in children and adolescents improved significantly (Figure 3). The survival of MDS and JMML however, has reached a plateau at approximately 50% following stem cell transplantation, which is the only curative treatment option for these diseases

A comparison of the Muenster, SIOP Boston, Brock, Chang and CTCAEv4.03 ototoxicity grading scales applied to 3,799 audiograms of childhood cancer patients treated with platinum-based chemotherapy

Childhood cancer patients treated with platinums often develop hearing loss and the degree is classified accord

Insomnia Symptoms and Daytime Fatigue Co-Occurrence in Adolescent and Young Adult Childhood Cancer Patients in Follow-Up after Treatment:Prevalence and Associated Risk Factors

Simple Summary Insomnia symptoms and daytime fatigue significantly impact physical and psychosocial health. While these are common symptoms in pediatric oncology, relationships between these symptoms remain unclear. This study evaluated the prevalence of insomnia only, daytime fatigue only, the co-occurrence of insomnia and daytime fatigue symptoms, and associated risk factors in adolescent/young adult childhood cancer patients in follow-up after treatment. Results showed that around forty percent had insomnia and daytime fatigue symptoms, which often co-occurred. Risk factors that emerged were: female sex and co-morbidities (all), shorter time after treatment and bedtime gaming (insomnia only), young adulthood (insomnia-fatigue and fatigue only), needing someone else to fall asleep and inconsistent wake times (both insomnia groups), and lower educational level and consistent bedtimes (insomnia-fatigue). Overall, insomnia symptoms and daytime fatigue were common and often co-occurred in this patient population. While current fatigue guidelines do not include insomnia symptoms, healthcare providers should inquire about insomnia as this potentially provides additional options for treatment and prevention. Insomnia symptoms and daytime fatigue commonly occur in pediatric oncology, which significantly impact physical and psychosocial health. This study evaluated the prevalence of insomnia only, daytime fatigue only, the co-occurrence of insomnia-daytime fatigue symptoms, and associated risk factors. Childhood cancer patients (n = 565, 12-26 years old, >= 6 months after treatment) participated in a national, cross-sectional questionnaire study, measuring insomnia symptoms (ISI; Insomnia Severity Index) and daytime fatigue (single item). Prevalence rates of insomnia and/or daytime fatigue subgroups and ISI severity ranges were calculated. Multinomial regression models were applied to assess risk factors. Most patients reported no insomnia symptoms or daytime fatigue (61.8%). In the 38.2% of patients who had symptoms, 48.1% reported insomnia and daytime fatigue, 34.7% insomnia only, and 17.1% daytime fatigue only. Insomnia scores were higher in patients with insomnia-daytime fatigue compared to insomnia only (p < 0.001). Risk factors that emerged were: female sex and co-morbidities (all), shorter time after treatment and bedtime gaming (insomnia only), young adulthood (insomnia-fatigue/fatigue only), needing someone else to fall asleep and inconsistent wake times (both insomnia groups), lower educational level and consistent bedtimes (insomnia-fatigue). Insomnia symptoms and daytime fatigue are common and often co-occur. While current fatigue guidelines do not include insomnia symptoms, healthcare providers should inquire about insomnia as this potentially provides additional options for treatment and prevention

LIN28B overexpression defines a novel fetal-like subgroup of juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a rare and aggressive stem cell disease of early childhood. RAS activation constitutes the core component of oncogenic signaling. In addition, leukemic blasts in one-fourth of JMML patients present with monosomy 7, and more than half of patients show elevated age-adjusted fetal hemoglobin (HbF) levels. Hematopoietic stem cell transplantation is the current standard of care and results in an event-free survival rate of 50% to 60%, indicating that novel molecular-driven therapeutic options are urgently needed. Using gene expression profiling in a series of 82 patient samples, we aimed at understanding the molecular biology behind JMML and identified a previously unrecognized molecular subgroup characterized by high LIN28B expression. LIN28B over expression was significantly correlated with higher HbF levels, whereas patients with monosomy 7 seldom showed enhanced LIN28B expression. This finding gives a biological explanation of why patients with monosomy7 are rarely diagnosed with high age-adjusted HbF levels. In addition, this new fetal-like JMML subgroup presented with reduced levels of most members of the let-7 microRNA family and showed characteristic overexpression of genes involved in fetal hematopoiesis and stem cell self-renewal. Lastly, high LIN28B expression was associated with poor clinical outcome in our JMML patient series but was not independent from other prognostic factors such as age and age-adjusted HbF levels. In conclusion, we identified elevated LIN28B expression as a hallmark of a novel fetal-like subgroup in JMM

TIMELESS Forms a Complex with PARP1 Distinct from Its Complex with TIPIN and Plays a Role in the DNA Damage Response

SummaryPARP1 is the main sensor of single- and double-strand breaks in DNA and, in building chains of poly(ADP-ribose), promotes the recruitment of many downstream signaling and effector proteins involved in the DNA damage response (DDR). We show a robust physical interaction between PARP1 and the replication fork protein TIMELESS, distinct from the known TIMELESS-TIPIN complex, which activates the intra-S phase checkpoint. TIMELESS recruitment to laser-induced sites of DNA damage is dependent on its binding to PARP1, but not PARP1 activity. We also find that the PARP1-TIMELESS complex contains a number of established PARP1 substrates, and TIMELESS mutants unable to bind PARP1 are impaired in their ability to bind PARP1 substrates. Further, PARP1 binding to certain substrates and their recruitment to DNA damage lesions is impaired by TIMELESS knockdown, and TIMELESS silencing significantly impairs DNA double-strand break repair. We hypothesize that TIMELESS cooperates in the PARP1-mediated DDR

Self-reported outcomes on oral health and oral health-related quality of life in long-term childhood cancer survivors—A DCCSS-LATER 2 Study

Purpose: The present study aimed to determine the prevalence of self-reported oral problems and the oral health–related quality of life (OHRQoL) in childhood cancer survivors (CCS). Methods: Patient and treatment characteristics of CCS have been collected in a cross-sectional study, part of the multidisciplinary DCCSS-LATER 2 Study. To assess self-reported oral health problems and dental problems, CCS filled out the ‘Toegepast-Natuurwetenschappelijk Onderzoek’ (TNO) oral health questionnaire. OHRQoL was assessed by the Dutch version of the Oral Health Impact Profile-14 (OHIP-14). Prevalences were compared with two comparison groups from the literature. Univariable and multivariable analyses were performed. Results: A total of 249 CCS participated in our study. The OHIP-14 total score had a mean value of 1.94 (sd 4.39), with a median score of 0 (range 0–29). The oral problems ‘oral blisters/aphthae’ (25.9%) and ‘bad odor/halitosis’ (23.3%) were significantly more often reported in CCS than in comparison groups (12% and 12%, respectively). The OHIP-14 score was significantly correlated with the number of self-reported oral health problems (r =.333, p&lt;0.0005) and dental problems (r =.392, p &lt;0.0005). In multivariable analysis, CCS with a shorter time since diagnosis (10-19 years vs. ≥30 years) had a 1.47-fold higher risk of ≥1 oral health problem. Conclusion: Though the perceived oral health is relatively good, oral complications following childhood cancer treatment are prevalent in CCS. This underlines that attention to impaired oral health and awareness on this topic is mandatory and regular visits to the dentist should be a part of long-term follow-up care.</p

Psychosexual development, sexual functioning and sexual satisfaction in long-term childhood cancer survivors:DCCSS-LATER 2 sexuality substudy

Objectives: Childhood cancer may negatively impact childhood cancer survivors' (CCS) sexuality. However, this is an understudied research area. We aimed to describe the psychosexual development, sexual functioning and sexual satisfaction of CCS, and identify determinants for these outcomes. Secondarily, we compared the outcomes of a subsample of emerging adult CCS to the Dutch general population. Methods: From the Dutch Childhood Cancer Survivor Study LATER cohort (diagnosed 1963–2001), 1912 CCS (18–71 years, 50.8% male) completed questions on sexuality, psychosocial development, body perception, mental and physical health. Multivariable linear regressions were used to identify determinants. Sexuality of CCS age 18–24 (N = 243) was compared to same-aged references using binomial tests and t-tests. Results: One third of all CCS reported hindered sexuality due to childhood cancer, with insecure body the most often reported reason (44.8%). Older age at study, lower education, surviving central nervous system cancer, poorer mental health and negative body perception were identified as determinants for later sexual debut, worse sexual functioning and/or sexual satisfaction. CCS age 18–24 showed significantly less experience with kissing (p = 0.014), petting under clothes (p = 0.002), oral (p = 0.016) and anal sex (p = 0.032) when compared to references. No significant differences with references were found for sexual functioning and sexual satisfaction, neither among female CCS nor male CCS age 18–24. Conclusions: Emerging adult CCS reported less experience with psychosexual development, but similar sexual functioning and sexual satisfaction compared to references. We identified determinants for sexuality, which could be integrated in clinical interventions for CCS at risk for reduced sexuality.</p

A detailed insight in the high risks of hospitalizations in long-term childhood cancer survivors-A Dutch LATER linkage study

Background Insight in hospitalizations in long-term childhood cancer survivors (CCS) is useful to understand the impact of long-term morbidity. We aimed to investigate hospitalization rates and underlying types of diagnoses in CCS compared to matched controls, and to investigate the determinants. Me

The Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis examined long-term glomerular dysfunction in childhood cancer survivors

This investigation aimed to evaluate glomerular dysfunction among childhood cancer survivors in comparison with matched controls from the general population. In the Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis, a nationwide cross-sectional cohort study, 1024 survivors five or more years after diagnosis, aged 18 or more years at study, treated between 1963-2001 with nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide or hematopoietic stem cell transplantation participated. In addition, 500 age- and sex-matched controls from Lifelines, a prospective population-based cohort study in the Netherlands, participated. At a median age of 32.0 years (interquartile range 26.6-37.4), the glomerular filtration rate was under 60 ml/min/1.73m2 in 3.7% of survivors and in none of the controls. Ten survivors had kidney failure. Chronic kidney disease according to age-thresholds (glomerular filtration rate respectively under 75 for age under 40, under 60 for ages 40-65, and under 40 for age over 65) was 6.6% in survivors vs. 0.2% in controls. Albuminuria (albumin-to-creatinine ratio over3 mg/mmol) was found in 16.2% of survivors and 1.2% of controls. Risk factors for chronic kidney disease, based on multivariable analyses, were nephrectomy (odds ratio 3.7 (95% Confidence interval 2.1-6.4)), abdominal radiotherapy (1.8 (1.1-2.9)), ifosfamide (2.9 (1.9-4.4)) and cisplatin over 500 mg/m2 (7.2 (3.4-15.2)). For albuminuria, risk factors were total body irradiation (2.3 (1.2-4.4)), abdominal radiotherapy over 30 Gy (2.6 (1.4- 5.0)) and ifosfamide (1.6 (1.0-2.4)). Hypertension and follow-up 30 or more years increased the risk for glomerular dysfunction. Thus, lifetime monitoring of glomerular function in survivors exposed to these identified high risk factors is warranted.</p