BackgroundTesticular cancer (TC) survivors have an increased risk of various second primary malignancies. A recent cohort study detected an increased risk of colorectal cancer (CRC) in TC survivors... Show moreBackgroundTesticular cancer (TC) survivors have an increased risk of various second primary malignancies. A recent cohort study detected an increased risk of colorectal cancer (CRC) in TC survivors treated with platinum-based chemotherapy with a hazard ratio of 3.9. CRC risk increased with higher cisplatin-dose. We know that colonoscopy surveillance in high-risk populations results in reduced incidence and mortality of CRC. TC survivors treated with platinum-based chemotherapy can potentially benefit from colonoscopy surveillance; however, to which extent is unknown. Furthermore, the pathogenesis of these secondary CRCs is unknown, and better insights into the carcinogenesis may affect surveillance decisions.MethodsThis prospective multicenter study will be performed in four Dutch hospitals. TC survivors are eligible if treated with >= 3 cycles of cisplatin before age 50. Colonoscopy will be performed >= 8 years after initial treatment (minimum and maximum ages at colonoscopy, 35 and 75 years, respectively). The primary aim of the study is the diagnostic yield of advanced neoplasia detected during colonoscopy. As secondary aim, we will evaluate the molecular profile of advanced colorectal neoplasia and will assess current platinum levels in blood and urine and correlate blood-platinum levels with prevalence of colorectal lesions. Furthermore, we will investigate effectiveness of fecal immunochemical testing (FIT) and burden of colonoscopy by two questionnaires. Demographic data, previous history, results of colonoscopy, hemoglobin level of FIT and results of molecular and platinum levels will be obtained. Yield of colonoscopy will be determined by detection rate of adenoma and serrated lesions, advanced adenoma detection rate and CRC detection rate. The MISCAN model will be used for cost-effectiveness analyses of CRC surveillance. With 234 participants undergoing colonoscopy, we can detect an absolute difference of 6% of advanced neoplasia with 80% power.DiscussionTC survivors treated with cisplatin-based chemotherapy can benefit from CRC surveillance. Evaluation of the diagnostic performance and patient acceptance of CRC surveillance is of importance to develop surveillance recommendations. Insight into the carcinogenesis of cisplatin-related advanced colorectal lesions will contribute to CRC prevention in the increasing number of TC survivors. The results may also be important for the many other cancer survivors treated with platinum-based chemotherapy.Trial registrationClinical Trials: NCT04180033, November 27, 2019, https://clinicaltrials.gov/ct2/show/NCT04180033. Show less
Post, R.S. van der; Vogelaar, I.P.; Manders, P.; Kolk, L.E. van der; Cats, A.; Hest, L.P. van; ... ; Ligtenberg, M.J.L. 2015
DNA damage, mutations and genomic instability are established driving forces of cancer and other age-related diseases. Mutations in tumor suppressor genes and oncogenes are very frequently found in... Show moreDNA damage, mutations and genomic instability are established driving forces of cancer and other age-related diseases. Mutations in tumor suppressor genes and oncogenes are very frequently found in tumors and genomic instability is the most common enabling characteristic of cancer. Aging is also believed to be enabled, amongst others, by genomic instability. DNA repair pathways, like the nucleotide excision repair (NER) pathway and cell cycle control (e.g. p53-dependent) processes are therefore vital to organisms, since these processes counteract or prevent genomic instability, and are thought to underlie, when affected, aging and age-related diseases like cancer. To unravel the functions, mechanisms and pathways involved in the onset of aging and age-related diseases we have investigated several mouse models deficient in either DNA repair (NER) capacity (Chapter 3, 4), cell cycle control (p53) (Chapter 6) or both (Chapter 5), and compared this to a wild type situation (Chapter 2). The use of mouse models enabled us to investigate cancer and aging in a controlled environment, minimizing possible confounding factors. Additionally, the mouse models can be useful as an alternative tool to identify genotoxic and non-genotoxic carcinogens that can be harmful to the society and the environment (Chapter 5). Show less
HPT-JT syndrome is a rare disease characterized by parathyroid tumours (with a high percentage of carcinomas), jaw and kidney tumours. In this thesis, the clinical and genetic features of the HPT... Show moreHPT-JT syndrome is a rare disease characterized by parathyroid tumours (with a high percentage of carcinomas), jaw and kidney tumours. In this thesis, the clinical and genetic features of the HPT-JT syndrome and the relationship between the HRPT2 gene and parathyroid tumours were investigated. We report the identification of the HRPT2 gene, located on chromosome 1q, a gene encoding a protein referred to as parafibromin. Germ-line mutations in this gene are responsible for the HPT-JT syndrome and a part of the sporadic parathyroid carcinomas. Loss of parafibromin in immunohistochemical staining seems a promising marker in the diagnosis of parathyroid carcinomas. Furthermore, we tried to gain insight in the molecular mechanisms of parathyroid tumourigenesis to improve the accuracy of diagnosis of these tumours. Molecules such as APP, E-cadherin andCASR might play a role in HRPT2 driven tumourigenesis. Show less
The results presented in this thesis provide new information on the role of the p53.S389A point mutation in chemical-induced tumorigenesis. After DNA damage, p53 protein levels increase due to... Show moreThe results presented in this thesis provide new information on the role of the p53.S389A point mutation in chemical-induced tumorigenesis. After DNA damage, p53 protein levels increase due to several post-translational activation processes. Phosphorylation of p53.S389 seems to be partly required for optimal induction of these p53 protein levels. Next, target genes are either induced or repressed, and phosphorylation of p53.S389 seems essential for an optimal p53-related transcriptional response both endogenously (especially repressed genes) as well as after the induction of DNA damage. Than as a read-out system for the activation of different genes, several cellular responses (apoptosis, cell cycle arrest etc.) can be observed, which again seems partly dependent on p53.S389 phosphorylation. When these processes are adversely affected due to inadequate functioning of p53, like is the case in p53.S389A mutant mice, this might lead to increased risks of developing tumors. Indeed, two chronic carcinogenicity experiments revealed an increased sensitivity of the p53.S389A mutant mice for tumor development upon exposure to DNA damaging agents. In conclusion, knowledge about the in vivo relationship between DNA damage induction, regulation of p53 activity (in terms of cell cycle control and/or apoptosis), DNA repair (NER) and the development of cancer was obtained. Show less
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