Cancer immunotherapies utilizing immune checkpoint blockade (ICB) therapy targeting CTLA-4 and PD-1/PD-L1 relieve tumor-induced immune suppression and induce durable tumor regression. The use of... Show moreCancer immunotherapies utilizing immune checkpoint blockade (ICB) therapy targeting CTLA-4 and PD-1/PD-L1 relieve tumor-induced immune suppression and induce durable tumor regression. The use of ICB therapy have demonstrated remarkable therapeutic efficacy in a proportion of patients with melanoma. However, still a substantial percentage of patients does not respond (durable) to ICB treatment and many questions remain. Therefore, in this thesis, the aim is to improve our understanding of ICB efficacy. We demonstrate the promise of neoadjuvant ICB therapy (approach in which ICB therapy is applied before surgery) and analyze different cohorts of melanoma patients. This results in the identification of several markers that are associated with prognosis, including IFN-y related gene signature score, Batf3 dendritic cell associated gene signature score, tumor mutational burden and systemic LRG1 expression. These markers can potentially be targeted and might facilitate rational combination therapies that can boost the efficacy of ICB therapy. For this purpose, we perform a repurposing compound screen that targets antigen cross-presentation. Togethers, this work increases our understanding of factors that determine ICB therapy efficacy and toxicity, with the goal to identify novel strategies to improve outcome of melanoma patients in a rationale and personal manner. Show less
While immune checkpoint blockade (ICB) (CTLA4/ PD1) therapy has resulted in durable responses in patients with advanced stage cutaneous melanoma, some patients do not benefit from this, due to... Show moreWhile immune checkpoint blockade (ICB) (CTLA4/ PD1) therapy has resulted in durable responses in patients with advanced stage cutaneous melanoma, some patients do not benefit from this, due to resistance mechanisms. This thesis aims to improve response of a subset of melanoma patients to immunotherapy. Firstly, mouse melanoma tumor models are developed that closely resemble some of the resistance mechanisms occurring in patient tumors, which are useful for research. Thereafter, a prognostic biomarker is used to identify the subset of melanoma patients that are unlikely to benefit from ICB therapy. It is then evaluated whether this subset of patients would benefit from combining histone deacetylase inhibitor with ICB. Despite encouraging pre-clinical results showing enhanced anti-tumor immune responses using this combination, this did not result in improved responses in the clinic. Furthermore, this thesis focuses on an immune cell subset, namely regulatory T cells (Tregs), which are known to suppress anti-tumor immune responses. Thus, their presence in the tumor microenvironment (TME) is detrimental to tumor cell killing. This thesis provides an increased understanding of the metabolic adaptation of Tregs to conditions in the TME and propose that targeting these adaptations might overcome the suppression by Tregs and enhance responses to immunotherapy. Show less
The aim of this thesis was to investigate if a text-mining tool is suitable for collecting real-world data from electronic health records to evaluate cancer treatments in clinical practice. By... Show moreThe aim of this thesis was to investigate if a text-mining tool is suitable for collecting real-world data from electronic health records to evaluate cancer treatments in clinical practice. By investigating a range of use cases including treatments of patients with renal cell carcinoma, hepatocellular carcinoma, melanoma, breast cancer, and COVID-19, it showed that the text-mining tool is a suitable method of data needed for the evaluation of treatment patterns, effectiveness, safety, prognostic factors, and guideline adherence. The discussion showed that enhancing the data quality and actively using real-world data for treatment evaluation regarding treatment policies are some of the next steps. Show less
Communication between cells is essential for the proper function of tissues in the human body. In cancer, this communication is disrupted. The signaling pathway initiated by Transforming Growth... Show moreCommunication between cells is essential for the proper function of tissues in the human body. In cancer, this communication is disrupted. The signaling pathway initiated by Transforming Growth Factor beta (TGF-beta) signaling molecules controls many processes in cells, including cell division, cell differentiation and cell migration. Dysregulation of TGF-beta signaling contributes to the formation and progression of many cancers. The inhibition of the TGF-beta signaling pathway is therefore an attractive anti-cancer therapy. Unfortunately, these therapies result in many side effects. The research described in this thesis aims to better understand TGF-beta signaling in different types of cancer. Through the development of new fluorescent tools, the activity and dynamics of TGF-beta signaling can be better studied in vitro and in vivo. In melanoma, the tumor microenvironment appeared to influence the effect of TGF-beta. In cervical cancer, TGF-beta activity levels could distinguish two subtypes of cervical cancer. In bladder cancer, a E3 ubiquitin ligase mediated a balance of BMP signaling, affecting bladder cancer progression. These studies all highlight the complexity of TGF-beta signaling and the need to fully understand TGF-beta signaling in different contexts to improve the use TGF-beta inhibition based therapies in the clinic. Show less
PurposeHeavy pigmentation is known to be a prognostic risk factor in uveal melanoma (UM). We analyzed whether genetic tumor parameters were associated with tumor pigmentation and whether... Show morePurposeHeavy pigmentation is known to be a prognostic risk factor in uveal melanoma (UM). We analyzed whether genetic tumor parameters were associated with tumor pigmentation and whether pigmentation should be included in prognostic tests.DesignRetrospective comparison of clinical, histopathological, and genetic features and survival in UM with different pigmentation.ParticipantsA total of 1058 patients with UM from a White European population with diverse eye colors enucleated between 1972 and 2021.MethodsCox regression and log-rank tests were used for survival analysis; the chi-square test and Mann–Whitney U test were used for correlation analysis.Main Outcome MeasuresUveal melanoma–related survival based on tumor pigmentation and chromosome status, correlation of tumor pigmentation with prognostic factors.ResultsThe 5-year UM-related mortality was 8% in patients with nonpigmented tumors (n = 54), 25% with lightly pigmented tumors (n = 489), 41% with moderately pigmented tumors (n = 333), and 33% with dark tumors (n = 178) (P < 0.001). The percentage of tumors with monosomy 3 (M3) or 8q gain increased with increasing pigmentation (31%, 46%, 62%, and 70% having M3 [P < 0.001], and 19%, 43%, 61%, and 63% having 8q gain [P < 0.001] in the 4 increasing pigment groups, respectively). BRCA-associated protein 1(BAP1) loss (known for 204 cases) was associated with increased tumor pigmentation (P = 0.001). Cox regression analysis on survival showed that when chromosome status and pigmentation were both included, pigmentation was not an independent prognostic indicator. Preferentially expressed antigen in melanoma (PRAME) expression was a significant prognostic marker in light tumors (P = 0.02) but not in dark tumors (P = 0.85).ConclusionsPatients with moderately and heavily pigmented tumors showed a significantly higher UM-related mortality than patients with unpigmented and light tumors (P < 0.001), supporting prior reports on the relation between increased tumor pigmentation and a worse prognosis. Although we previously showed that a dark eye color was associated with tumor pigmentation, we now show that the tumor’s genetic status (chromosome 3 and 8q/BAP1 status) is also related to tumor pigmentation. When pigmentation and chromosome 3 status are both included in a Cox regression analysis, pigmentation is not an independent prognostic factor. However, evidence from this and previous studies shows that chromosome changes and PRAME expression have a stronger association with survival when they occur in light tumors than in dark ones. Show less
This thesis aims to improve the treatment of patients with stage III melanoma. The first part describes different aspects of treatment with Talimogene Laherparepvec (T-VEC), a genetically modified... Show moreThis thesis aims to improve the treatment of patients with stage III melanoma. The first part describes different aspects of treatment with Talimogene Laherparepvec (T-VEC), a genetically modified herpes virus, which is used as oncolytic immunotherapy for skin and lymph node metastases in melanoma patients. We show that patients with a low tumor burden have the best outcomes, suggesting T-VEC should be used earlier on in the course of the disease. We present a prediction model, allowing a more accurate selection of patients for T-VEC monotherapy. Two studies focused on the use of T-VEC in clinical practice and the results allowed us to make recommendations on the use of PET/CT and dermoscopy during T-VEC treatment. Part two focuses on the value of surveillance and screening imaging in high-risk melanoma patients. We show that FDG-PET/CT is a valuable imaging tool to detect recurrence after complete resection of stage III disease, even shortly after surgery (before starting adjuvant therapy). Finally, we conclude that nodal staging with US as adjunct to SLNB is useful in the work- up of stage IIB/C melanoma, as it can lead to alterations in treatment and prevent unnecessary surgery. Show less
BackgroundPatients diagnosed with haematologic malignancies (HMs) have a higher risk of developing subsequent solid tumours, such as melanoma. Patients with HM were mostly excluded from clinical...Show moreBackgroundPatients diagnosed with haematologic malignancies (HMs) have a higher risk of developing subsequent solid tumours, such as melanoma. Patients with HM were mostly excluded from clinical trials but potentially derive less benefit from immune checkpoint inhibitors (ICIs) due to disease- or treatment-related T- or B-cell dysfunction.MethodsAll advanced melanoma patients treated with anti-PD-1-based treatment or targeted therapy between 2015 and 2021 were included from the prospective nationwide Dutch Melanoma Treatment Registry. Progression-free survival (PFS) and melanoma-specific survival (MSS) were analysed for patients with HM (HM+) and without HM (HM−). A cox model was used to account for confounders associated with PFS and MSS.ResultsIn total, 4638 advanced melanoma patients received first-line anti-PD-1 monotherapy (n = 1763), ipilimumab-nivolumab (n = 800), or BRAF(/MEK) inhibitors (n = 2075). Concurrent HMs were present for 46 anti-PD1-treated patients, 11 ipilimumab-nivolumab-treated patients and 43 BRAF(/MEK)-inhibitor-treated patients. In anti-PD-1-treated patients, the median PFS was 2.8 months for HM+ and 9.9 months for HM− (p = 0.01). MSS was 41.2 months for HM+ and 58.1 months for HM− (p = 0.00086). In multivariable analysis, the presence of an HM was significantly associated with higher risk of melanoma progression (HRadj 1.62; 95% confidence interval [95% CI] 1.15–2.29; p = 0.006) and melanoma-related death (HRadj 1.74; 95% CI 1.09–2.78; p = 0.020). Median PFS and MSS for first-line BRAF(/MEK-) inhibitor-treated HM+ and HM− patients were not significantly different.ConclusionsPatients with HM and advanced melanoma show significantly worse melanoma-related outcomes when treated with ICI, but not targeted therapy, compared to patients without HM. Clinicians should be aware of potentially altered effectiveness of ICI in patients with active HM. Show less
Background: The gut microbiome plays an important role in immune modulation. Specifically, presence or absence of certain gut bacterial taxa has been associated with better antitumor immune... Show moreBackground: The gut microbiome plays an important role in immune modulation. Specifically, presence or absence of certain gut bacterial taxa has been associated with better antitumor immune responses. Furthermore, in trials using fecal microbiota transplantation (FMT) to treat melanoma patients unresponsive to immune checkpoint inhibitors (ICI), complete responses (CR), partial responses (PR), and durable stable disease (SD) have been observed. However, the underlying mechanism determining which patients will or will not respond and what the optimal FMT composition is, has not been fully elucidated, and a discrepancy in microbial taxa associated with clinical response has been observed between studies. Furthermore, it is unknown whether a change in the microbiome itself, irrespective of its origin, or FMT from ICI responding donors, is required for reversion of ICI-unresponsiveness. To address this, we will transfer microbiota of either ICI responder or nonresponder metastatic melanoma patients via FMT. Methods: In this randomized, double-blinded phase Ib/IIa trial, 24 anti-PD1-refractory patients with advanced stage cutaneous melanoma will receive an FMT from either an ICI responding or nonresponding donor, while continuing anti-PD-1 treatment. Donors will be selected from patients with metastatic melanoma treated with anti-PD-1 therapy. Two patients with a good response (& GE; 30% decrease according to RECIST 1.1 within the past 24 months) and two patients with progression (& GE; 20% increase according to RECIST 1.1 within the past 3 months) will be selected as ICI responding or nonresponding donors, respectively. The primary endpoint is clinical benefit (SD, PR or CR) at 12 weeks, confirmed on a CT scan at 16 weeks. The secondary endpoint is safety, defined as the occurrence of grade & GE; 3 toxicity. Exploratory endpoints are progression-free survival and changes in the gut microbiome, metabolome, and immune cells. Discussion: Transplanting fecal microbiota to restore the patients' perturbed microbiome has proven successful in several indications. However, less is known about the potential role of FMT to improve antitumor immune response. In this trial, we aim to investigate whether administration of FMT can reverse resistance to anti-PD-1 treatment in patients with advanced stage melanoma, and whether the ICI-responsiveness of the feces donor is associated with its effectiveness. Show less
Single-agent Talimogene Laherparepvec (T-VEC) was developed for treatment of unresectable and injectable stage III-IV melanoma. Since its approval and reimbursement, studies have reported varying... Show moreSingle-agent Talimogene Laherparepvec (T-VEC) was developed for treatment of unresectable and injectable stage III-IV melanoma. Since its approval and reimbursement, studies have reported varying response rates. The purpose of this systematic review and meta-analysis was to investigate the efficacy and safety of T-VEC. Of 341 publications that were identified, eight studies with a total of 642 patients were included. In patients with stage IIIB-IVM1a, the pooled complete-and overall response rate (CRR and ORR) were 41% and 64%, respectively. In patients with stage IIIB-IVM1c, the pooled CRR and ORR were 30% and 44%, respectively. In patients with stage IVM1b and IVM1c, the pooled CRR and ORR were 4% and 9%, respectively. Adverse events (AEs) were seen in 41-100% of all patients and 0-11% of AEs were severe. In conclusion, single agent T-VEC achieves the highest response rates in patients with early metastatic melanoma and is well-tolerated with generally only mild toxicities. Show less
Death in all types of melanomas is generally caused by metastasis. Uveal melanoma (UM) is the most common intraocular melanoma, there are currently no (patient-derived) animal models that... Show moreDeath in all types of melanomas is generally caused by metastasis. Uveal melanoma (UM) is the most common intraocular melanoma, there are currently no (patient-derived) animal models that faithfully recapitulate metastatic dissemination of UM. Here we generate embryonic zebrafish models for both the primary and disseminated stage of ocular melanoma. In doing so we can recapitulate the etiology of cancer in its totality. Subsequently, we developed a patient-derived zebrafish xenograft (zf-PDX) model, using spheroid cultures generated from metastatic and primary UM tissues. Harnessing this versatile model, we reveal high sensitivity of circulating UM cells to ferroptosis induction in vivo by Erastin and RSL3, implicating ferroptosis as a new potential therapy in metastatic UM.Increased melanin levels in cutaneous melanoma are associated with decreased patient survival. Melanin levels in primary uveal melanoma patient cells positively correlate with their metastatic potential in zebrafish. Modulation of melanin levels of pan-melanoma cells results in enhanced/reduced metastatic potential upon increased or decreased melanin levels, respectively. Melanin depletion sensitizes melanoma cells to ferroptosis inducers in zebrafish leading to a decreased metastatic burden. Collectively, our data identify melanin biosynthetic enzymes as potential future target to treat melanoma and show that melanin protects metastasizing melanoma cells from ferroptosis. Show less
Background: Recent reports suggest the limited efficacy of immune checkpoints inhibitors in advanced acral melanoma (AM). This study aims to investigate the clinical outcomes of immune checkpoint... Show moreBackground: Recent reports suggest the limited efficacy of immune checkpoints inhibitors in advanced acral melanoma (AM). This study aims to investigate the clinical outcomes of immune checkpoint inhibitors in patients with stage III and IV AM and compare them to cutaneous melanoma (CM). Methods: We included patients with advanced AM and CM treated with first-line anti -programmed cell death (PD)-1 monotherapy or ipilimumab-nivolumab registered in the prospective nationwide Dutch Melanoma Treatment Registry. Objective response rates, progression free survival (PFS) and overall survival (OS) were calculated. A Cox proportional hazard model was used to assess the prognostic factors with PFS and OS. Results: In total, 2058 patients (88 AM and 1970 CM) with advanced melanoma were included. First-line objective response rates were 34% for AM versus 54% for CM in the advanced anti-PD-1 cohort and 33% for AM versus 53% for CM in the advanced ipilimumab-nivolumab cohort. The Median PFS was significantly shorter for anti-PD-1 treated AM patients (3.1 months; 95%CI: 2.8-5.6) than patients with CM (10.1 months; 95%CI: 8.5-12.2) (P < 0.001). In patients with advanced melanoma, AM was significantly associated with a higher risk of progression (HRadj 1.63; 95%CI: 1.26-2.11 ; P < 0.001) and death (HRadj 1.54; 95%CI: 1.15-2.06; P Z 0.004) than CM. Conclusions: This study shows lower effectiveness of anti-PD-1 monotherapy and ipilimumab-nivolumab in AM, with lower response rates, PFS and OS than CM. This group of patients should be prioritised in the development of alternative treatment strategies. 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
Ocular melanoma is a rare disease that originates from melanocytes in the eye. It is the most prevalent primary ocular malignancy in adults, and has a high metastatic rate. Two important questions... Show moreOcular melanoma is a rare disease that originates from melanocytes in the eye. It is the most prevalent primary ocular malignancy in adults, and has a high metastatic rate. Two important questions for good patient care are: 1) How to differentiate between (benign) nevi, and (malignant) melanoma?, and 2) How to treat this tumor best, particularly in cases with metastases?This thesis addresses two types of ocular melanoma: melanoma of the internal parts of the eye (uveal melanoma) and melanoma of the mucous membrane covering the eye (conjunctival melanoma). This thesis combines patient-related projects with projects from the lab.With new imaging techniques we demonstrate that oxygen values differ in eyes with melanoma compared to other eyes including those with a nevus. We use OCT-angiography to depict tumour vessels non-invasively in conjunctival and iris lesions. These two techniques may be used in the future to differentiate lesions, and to monitor patients after treatment.With studies in the lab we show that new drugs (immunotherapy) that are recently used in cutaneous melanoma, can also be used to treat conjunctival melanoma. We show that vascular growth in uveal melanoma is related to other (genetic and immunologic) characteristics, providing new clues for therapy. Show less
Although clinical aspects of melanoma have been extensively studied, the literature largely concerns relatively healthy 20-70 years old patients. Special populations, such as the elderly, children,... Show moreAlthough clinical aspects of melanoma have been extensively studied, the literature largely concerns relatively healthy 20-70 years old patients. Special populations, such as the elderly, children, patients with multiple primary melanoma and those with familial melanoma, are frequently excluded from clinical studies. The studies presented in this thesis were aimed to assess prognostic factors and management of patients with clinically localized melanoma, in particular among the aforementioned special populations. Show less
Melanoma is the most aggressive and lethal type of skin cancer since it has the ability to spread to other organs in the body making it harder to control the disease.In this thesis, we aim to... Show moreMelanoma is the most aggressive and lethal type of skin cancer since it has the ability to spread to other organs in the body making it harder to control the disease.In this thesis, we aim to explore the degree to which epigenetics play a role in melanoma, namely, inherited and acquired epigenetic alterations in melanoma susceptibility and development. Show less
Background: Checkpoint inhibitors have changed overall survival for patients with advanced melanoma. However, there is a lack of data on health-related quality of life (HRQoL) of long-term advanced... Show moreBackground: Checkpoint inhibitors have changed overall survival for patients with advanced melanoma. However, there is a lack of data on health-related quality of life (HRQoL) of long-term advanced melanoma survivors, years after treatment. Therefore, we evaluated HRQoL in long-term advanced melanoma survivors and compared the study outcomes with matched controls without cancer.Material and methods: Ipilimumab-treated advanced melanoma survivors without evidence of disease and without subsequent systemic therapy for a minimum of two years following last administration of ipilimumab were eligible for this study. The European Organization for Research and Treatment of Cancer quality of life questionnaire Core 30 (EORTC QLQ-C30), the Multidimensional Fatigue Inventory (MFI), the Hospital Anxiety and Depression Scale (HADS), and the Functional Assessment of Cancer Therapy-Melanoma questionnaire (FACT-M) were administered. Controls were individually matched for age, gender, and educational status. Outcomes of survivors and controls were compared using generalized estimating equations, and differences were interpreted as clinically relevant according to published guidelines.Results: A total of 89 survivors and 265 controls were analyzed in this study. After a median follow-up of 39 (range, 17-121) months, survivors scored significantly lower on physical (83.7vs. 89.8, difference (diff) = -5.80,p=.005), role (83.5vs.90, diff = -5.97,p=.02), cognitive (83.7vs.91.9, diff = -8.05,p=.001), and social functioning (86.5vs.95.1, diff = -8.49,p= <.001) and had a higher symptom burden of fatigue (23.0vs.15.5, diff = 7.48,p=.004), dyspnea (13.3vs.6.7, diff = 6.47p=.02), diarrhea (7.9vs.4.0, diff = 3.78,p=.04), and financial impact (10.5vs.2.5, diff = 8.07,p=.001) than matched controls. Group differences were indicated as clinically relevant.Discussion: Compared to matched controls, long-term advanced melanoma survivors had overall worse functioning scores, more physical symptoms, and financial difficulties. These data may contribute to the development of appropriate survivorship care. Show less
In summary, this thesis focused on the understanding the underlying mechanisms driving TNBC metastatic progression. We established DUB activity profiling methods and identified UCHL1 as a candidate... Show moreIn summary, this thesis focused on the understanding the underlying mechanisms driving TNBC metastatic progression. We established DUB activity profiling methods and identified UCHL1 as a candidate oncoprotein that promotes TGFβ-induced breast cancer metastasis. Importantly, we found UCHL1 activity inhibitor as a potential drug for TNBC therapy and developed UCHL1 activity-based probe. For vemurafenib-resistance melanoma, we provided insights that targeting TGFβ signaling may help to overcome drug resistant phenotype. Show less
Epidemiologic studies have reported inconsistent results regarding an association between Parkinson disease (PD) and cutaneous melanoma (melanoma). Identifying shared genetic architecture between... Show moreEpidemiologic studies have reported inconsistent results regarding an association between Parkinson disease (PD) and cutaneous melanoma (melanoma). Identifying shared genetic architecture between these diseases can support epidemiologic findings and identify common risk genes and biological pathways. Here, we apply polygenic, linkage disequilibrium-informed methods to the largest available case-control, genome-wide association study summary statistic data for melanoma and PD. We identify positive and significant genetic correlation (correlation: 0.17, 95% CI 0.10-0.24; P = 4.09 x 10(-06)) between melanoma and PD. We further demonstrate melanoma and PD-inferred gene expression to overlap across tissues (correlation: 0.14, 95% CI 0.06 to 0.22; P = 7.87 x 10(-04)) and highlight seven genes including PIEZO1, TRAPPC2L, and SOX6 as potential mediators of the genetic correlation between melanoma and PD. These findings demonstrate specific, shared genetic architecture between PD and melanoma that manifests at the level of gene expression. Show less
The aim of the research described in this thesis was to gain a better understanding of the role of the different immune cells and the different FcR on their cell surface, in antibody therapy and... Show moreThe aim of the research described in this thesis was to gain a better understanding of the role of the different immune cells and the different FcR on their cell surface, in antibody therapy and to investigate whether the effectiveness of the tumor-killing mechanisms, activated by the antibodies, can be improved. First, we investigated the role of FcR in various immune responses using a genetically modified mouse, in which all FcR were missing. After defining that role, we studied antibody therapy in a mouse model for melanoma in two different ways: on the one hand, after vaccination using a viral vector that expressed a melanoma antigen, on the other hand, by injecting a melanoma-specific antibody in combination with other substances that activate the immune system. Show less
Christodoulou, E.; Visser, M.; Potjer, T.P.; Stoep, N. van der; Rodriguez-Girondo, M.; Doorn, R. van; Gruis, N. 2019
Carriers of pathogenic variants in CDKN2A have a 70% life-time risk of developing melanoma and 15-20% risk of developing pancreatic cancer (PC). In the Netherlands, a 19-bp deletion in exon 2 of... Show moreCarriers of pathogenic variants in CDKN2A have a 70% life-time risk of developing melanoma and 15-20% risk of developing pancreatic cancer (PC). In the Netherlands, a 19-bp deletion in exon 2 of CDKN2A (p16-Leiden mutation) accounts for most hereditary melanoma cases. Clinical experience suggests variability in occurrence of melanoma and PC in p16-Leiden families. Thereby, the risk of developing cancer could be modified by both environmental and genetic contributors, suggesting that identification of genetic modifiers could improve patients' surveillance. In a recent genome-wide association study (GWAS), rs36115365-C was found to significantly modify risk of PC and melanoma in the European population. This SNP is located on chr5p15.33 and has allele-specific regulatory activities on TERT expression. Herein, we investigated the modifying capacities of rs36115365-C on PC and melanoma in a cohort of 283 p16-Leiden carriers including 29 diagnosed with PC, 171 diagnosed with melanoma, 21 diagnosed with both PC and melanoma and 62 with neither PC nor melanoma. In contrast to previously reported findings, we did not find a significant association of PC risk with risk variant presence as determined by Generalized Estimating Equations (GEE) modelling. Interestingly, carrier-ship of the risk variant had a significant protective effect for melanoma (OR - 0.703 [95% CI - 1.201 to - 0.205], p = 0.006); however, the observed association was no longer significant after exclusion of probands to assess possible influence of ascertainment. Collectively, genetic modifiers for the prediction of PC and melanoma risk in p16-Leiden carriers remain to be determined. Show less
Meijer, T.S.; Burgmans, M.C.; Fiocco, M.; Geus-Oei, L.F. de; Kapiteijn, E.; Leede, E.M. de; ... ; Vahrmeijer, A.L. 2019
