THE ADDED VALUE OF BLOOD GLUCOSE MONITORING IN HIGH-RISK INDIVIDUALS UNDERGOING PANCREATIC CANCER SURVEILLANCE

OBJECTIVES

The study aimed to investigate the added value of blood glucose monitoring in high-risk individuals (HRIs) participating in pancreatic cancer surveillance.

METHODS

HRIs with a CDKN2A/p16 germline pathogenic variant (PV) participating in pancreatic cancer surveillance were included in this study. Multivariable logistic regression was performed to assess the relationship between new-onset diabetes (NOD) and pancreatic ductal adenocarcinoma (PDAC). To quantify the diagnostic performance of NOD as a marker for PDAC, receiver operating characteristic curve with area under the curve (AUC) was computed.

RESULTS

In total, 220 HRIs were included between 2000-2019. Median age was 61 (IQR 53-71) years and 62.7% of participants were female. During the study period, 26 (11.8%) HRIs developed NOD, of whom 5 (19.2%) later developed PDAC. The other 23 (82.1%) PDAC cases remained NOD-free. Multivariable analysis showed no statistically significant relationship between NOD and PDAC (OR 1.21; 95% CI, 0.39-3.78) and four out of five PDAC cases appeared to have NOD within three months before diagnosis. Furthermore, NOD did not differentiate between HRIs with- and without PDAC (AUC 0.54; 95% CI, 0.46-0.61).

CONCLUSIONS

In this study we found no added value for longitudinal glucose monitoring in CDKN2A PV carriers participating in an imaging-based pancreatic cancer surveillance program.

Utilization and Outcomes of Multigene Panel Testing in Patients With Pancreatic Ductal Adenocarcinoma

PURPOSE

Guidelines recommend germline genetic testing (GT) for patients with pancreatic ductal adenocarcinoma (PDAC). This study aims to evaluate the utilization and outcomes of multigene panel GT in patients with PDAC.

METHODS

This retrospective, multisite study included patients with PDAC diagnosed between May 2018 and August 2020 at Mayo Clinic Arizona, Florida, and Minnesota. Discussion, uptake, and outcomes of GT were compared before (May 1, 2018-May 1, 2019) and after (August 1, 2019-August 1, 2020) the guideline update, accounting for a transition period.

RESULTS

The study identified 533 patients with PDAC, with 321 (60.2%) preguideline and 212 (39.8%) postguideline. Patient characteristics did not differ between the preguideline and postguideline periods. GT was discussed in 34.3% (110 of 321) of preguideline and 39.6% (84 of 212) of postguideline patients (odds ratio [OR], 1.26 [95% CI, 0.88 to 1.80]) and subsequently performed in 80.9% (89 of 110) of preguideline and 75.0% (63 of 84) of postguideline patients (OR, 1.10 [95% CI, 0.75 to 1.61]). Of 152 tested patients, 26 (17.1%) had a pathogenic variant (PV), of whom 17 (11.2%; 17 of 152) were PDAC-associated. Over the entire study period, GT was more likely in younger patients (65 v 70 years; P < .001), those seen by a medical oncologist (82.9% v 69.0%; P < .001), and those surviving more than 12 months from diagnosis (70.4% v 43.4%; P < .001). Demographics and personal/family cancer history were comparable between patients with and without a PDAC PV.

CONCLUSION

GT remains underutilized despite National Comprehensive Cancer Network guideline recommendations. Given the poor prognosis of PDAC and potential implications of GT, efforts to increase utilization are needed to provide surveillance and support to both patients with PDAC and at-risk family members.

Psychosocial issues of individuals undergoing surveillance for increased risk of melanoma and pancreatic cancer due to a germline CDKN2A variant: A focus group study

Individuals with a germline CDKN2A pathogenic variant (PV) are at high risk of developing melanoma and pancreatic cancer and are therefore offered surveillance. The potential advantages and disadvantages associated with genetic testing and surveillance are discussed during medical counseling, although little is known about the associated psychosocial factors that are relevant to this population. This study sought to provide a qualitative exploration of psychosocial factors related to genetic testing and participation in skin and pancreatic surveillance in (potential) carriers of a CDKN2A PV. Fifteen individuals-both at-risk individuals and confirmed variant carriers-participated in one of the three online focus groups. Pre-defined discussion topics, including genetic testing, cancer surveillance, influence on lifestyle and family planning, were discussed. Patients reported that important reasons to engage in genetic testing included the possibility to participate in surveillance to gain control over their cancer risk and to get clarification on the potential carrier status of their children. We observed considerable differences in risk perception and experienced burden of surveillance. Knowledge of the PV has had a positive influence on lifestyle factors and altered attitudes toward life in some. Most participants were not aware of preimplantation genetic testing. This focus group study provided insight into a variety of psychosocial themes related to (potential) carriership of a CDKN2A PV. Future efforts should focus on identifying those who may benefit from additional psychosocial support, development of a centralized source of information, and assessing the knowledge, needs, and timing of counseling for family planning.

Estimated Prevalence, Tumor Spectrum, and Neurofibromatosis Type 1-Like Phenotype of CDKN2A-Related Melanoma-Astrocytoma Syndrome

Importance

Knowledge about the prevalence and tumor types of CDKN2A-related melanoma-astrocytoma syndrome (MAS) is limited and could improve disease recognition.

Objective

To estimate the prevalence and describe the tumor types of MAS.

Design, Setting, and Participants

This retrospective cohort study analyzed all available MAS cases from medical centers in the US (2 sites) and Europe (2 sites) and from biomedical population genomic databases (UK Biobank [United Kingdom], Geisinger MyCode [US]) between January 1, 1976, and December 31, 2020. Patients with MAS with CDKN2A germline pathogenic variants and 1 or more neural tumors were included. Data were analyzed from June 1, 2022, to January 31, 2023.

Main Outcomes and Measures

Disease prevalence and tumor frequency.

Results

Prevalence of MAS ranged from 1 in 170 503 (n = 1 case; 95% CI, 1:30 098-1:965 887) in Geisinger MyCode (n = 170 503; mean [SD] age, 58.9 [19.1] years; 60.6% women; 96.2% White) to 1 in 39 149 (n = 12 cases; 95% CI, 1:22 396-1:68 434) in UK Biobank (n = 469 789; mean [SD] age, 70.0 [8.0] years; 54.2% women; 94.8% White). Among UK Biobank patients with MAS (n = 12) identified using an unbiased genomic ascertainment approach, brain neoplasms (4 of 12, 33%; 1 glioblastoma, 1 gliosarcoma, 1 astrocytoma, 1 unspecified type) and schwannomas (3 of 12, 25%) were the most common malignant and benign neural tumors, while cutaneous melanoma (2 of 12, 17%) and head and neck squamous cell carcinoma (2 of 12, 17%) were the most common nonneural malignant neoplasms. In a separate case series of 14 patients with MAS from the US and Europe, brain neoplasms (4 of 14, 29%; 2 glioblastomas, 2 unspecified type) and malignant peripheral nerve sheath tumor (2 of 14, 14%) were the most common neural cancers, while cutaneous melanoma (4 of 14, 29%) and sarcomas (2 of 14, 14%; 1 liposarcoma, 1 unspecified type) were the most common nonneural cancers. Cutaneous neurofibromas (7 of 14, 50%) and schwannomas (2 of 14, 14%) were also common. In 1 US family, a father and son with MAS had clinical diagnoses of neurofibromatosis type 1 (NF1). Genetic testing of the son detected a pathogenic CDKN2A splicing variant (c.151-1G>C) and was negative for NF1 genetic alterations. In UK Biobank, 2 in 150 (1.3%) individuals with clinical NF1 diagnoses had likely pathogenic variants in CDKN2A, including 1 individual with no detected variants in the NF1 gene.

Conclusions and Relevance

This cohort study estimates the prevalence and describes the tumors of MAS. Additional studies are needed in genetically diverse populations to further define population prevalence and disease phenotypes.

Surveillance for pancreatic cancer in high-risk individuals leads to improved outcomes: a propensity score-matched analysis

BACKGROUND & AIMS

Recent pancreatic cancer surveillance programs of high-risk individuals have reported improved outcomes. This study assessed to what extent outcomes of pancreatic ductal adenocarcinoma (PDAC) in patients with a CDKN2A/p16 pathogenic variant (PV) diagnosed under surveillance are better as compared to PDAC patients diagnosed outside surveillance.

METHODS

In a propensity score matched cohort using data from the Netherlands Cancer Registry (NCR), we compared resectability, stage and survival between patients diagnosed under surveillance with non-surveillance PDAC patients. Survival analyses were adjusted for potential effects of lead time.

RESULTS

Between January 2000 and December 2020, 43 762 patients with PDAC were identified from the NCR. Thirty-one patients with PDAC under surveillance were matched in a 1:5 ratio with 155 non-surveillance patients based on age at diagnosis, sex, year of diagnosis, and tumor location. Outside surveillance, 5.8% of the cases had stage I cancer, as compared to 38.7% of surveillance PDAC patients (OR 0.09; 95% CI, 0.04 - 0.19). In total, 18.7% of non-surveillance patients vs. 71.0% of surveillance patients underwent a surgical resection (OR 10.62; 95% CI, 4.56 - 26.63). Patients in surveillance had a better prognosis, reflected by a 5-year survival of 32.4% and a median overall survival (OS) of 26.8 months vs. 4.3% 5-year survival and 5.2 months median OS in non-surveillance patients (HR 0.31, 95% CI 0.19 - 0.50). For all adjusted lead times, survival remained significantly longer in surveillance patients than in non-surveillance patients.

CONCLUSION

Surveillance for PDAC in carriers of a CDKN2A/p16 PV results in earlier detection, increased resectability and improved survival as compared to non-surveillance PDAC patients.

Guideline compliance and outcomes of genetic testing in pancreatic cancer patients

688

Background: Guidelines recommend patients with pancreatic ductal adenocarcinoma (PDAC) undergo genetic testing for germline pathogenic variants (PV). The aim of this study was to evaluate compliance with recently updated guidelines (May 2019) and assess subsequent uptake and outcomes of genetic testing in PDAC patients. In addition, social and clinical factors associated with genetic testing were assessed. Methods: A retrospective chart review of patients diagnosed with PDAC between May 2018 and August 2020 was performed. Discussion and subsequent uptake of genetic testing was reviewed and compared between a 12-month period before (pre-guideline) and a 12-month period after (post-guideline) guidelines were updated, accounting for a three-month transition period. Univariate and multivariate logistic regression analysis was used to assess factors predictive of undergoing genetic testing. Results: In total, 534 patients with PDAC were identified; 321 (60.1%) in the pre-guideline period and 213 (39.9%) in the post-guideline period. The mean age at diagnosis was 68 years and 47% were female. Genetic testing was discussed in 34% (109/321) of pre-guideline and in 39% (84/213) of post-guideline patients ( P = .23). Of those, 82% (89/109) of patients in pre-guideline and 75% (63/84) in post-guideline groups underwent subsequent genetic testing ( P = .71). In 26 (17.1%) of 152 tested patients, a PV was identified, of which 17 (11.2%; 17/152) had a PDAC-associated PV. Age, cancer stage at diagnosis, length of survival, and having a first-degree relative with pancreatic cancer were significant predictors of genetic testing on multivariate analysis. Conclusions: Adherence to recently updated guidelines is poor and germline genetic testing in PDAC patients remains insufficient. Efforts to increase awareness of benefits of testing, which include personalized therapies for patients and cascade testing in family members for subsequent enrollment in pancreatic cancer surveillance programs, could improve future uptake.[Table: see text]

Comparison of pancreatic cancer outcomes diagnosed in surveillance and the general population: A propensity score-matched analysis

690

Background: Recent pancreatic cancer surveillance programs of high-risk individuals have reported improved outcomes. This study assessed to what extent outcomes of pancreatic ductal adenocarcinoma (PDAC) in patients with a CDKN2A/p16 pathogenic variant (PV) diagnosed during surveillance are better as compared to PDAC patients diagnosed outside surveillance. Methods: In a propensity score matched cohort using data from the Netherlands Cancer Registry, we compared resectability, stage and survival between patients diagnosed in surveillance with non-surveillance PDAC patients. Survival analysis were repeated after adjustment for lead-time bias. Results: Between January 2000 and December 2020, 43 762 patients with PDAC were identified from the NCR. Thirty-one patients with PDAC in surveillance were matched in a 1:5 ratio with 155 non-surveillance patients based on age at diagnosis, sex, and year of diagnosis. In total, 71% of patients in surveillance, as compared to 16% of non-surveillance patients underwent a surgical resection (OR 14.03; 95% CI, 5.92 – 35.85). In surveillance, 39% of patients was diagnosed with stage I cancer, as compared to 6% of non-surveillance PDAC patients (OR 0.10; 95% CI, 0.04 – 0.21). Patients in surveillance had a better prognosis, reflected by a 3-year survival of 32.4% and a median overall survival (OS) of 26.8 months vs. 1.4% 3-year survival and 5.3 months median OS in non-surveillance patients (HR 0.22; 95% 0.14 – 0.36). After adjustment for lead time, PDAC diagnosis in surveillance remained strongly associated with improved survival. Conclusions: Surveillance for PDAC in carriers of a CDKN2A/p16 PV results in earlier detection, increased resectability and improved survival as compared to non-surveillance PDAC patients.[Table: see text]

Pancreatic Cancer Surveillance in Carriers of a Germline CDKN2A Pathogenic Variant: Yield and Outcomes of a 20-Year Prospective Follow-Up

PURPOSE

Pancreatic cancer surveillance in high-risk individuals may lead to detection of pancreatic ductal adenocarcinoma (PDAC) at an earlier stage and with improved survival. This study evaluated the yield and outcomes of 20 years of prospective surveillance in a large cohort of individuals with germline pathogenic variants (PVs) in CDKN2A.

METHODS

Prospectively collected data were analyzed from individuals participating in pancreatic cancer surveillance. Surveillance consisted of annual magnetic resonance imaging with magnetic resonance cholangiopancreatography and optional endoscopic ultrasound.

RESULTS

Three hundred forty-seven germline PV carriers participated in surveillance and were followed for a median of 5.6 (interquartile range 2.3-9.9) years. A total of 36 cases of PDAC were diagnosed in 31 (8.9%) patients at a median age of 60.4 (interquartile range 51.3-64.1) years. The cumulative incidence of primary PDAC was 20.7% by age 70 years. Five carriers (5 of 31; 16.1%) were diagnosed with a second primary PDAC. Thirty (83.3%) of 36 PDACs were considered resectable at the time of imaging. Twelve cases (12 of 36; 33.3%) presented with stage I disease. The median survival after diagnosis of primary PDAC was 26.8 months, and the 5-year survival rate was 32.4% (95% CI, 19.1 to 54.8). Individuals with primary PDAC who underwent resection (22 of 31; 71.0%) had an overall 5-year survival rate of 44.1% (95% CI, 27.2 to 71.3). Nine (2.6%; 9 of 347) individuals underwent surgery for a suspected malignant lesion, which proved to not be PDAC, and this included five lesions with low-grade dysplasia.

CONCLUSION

This long-term surveillance study demonstrates a high incidence of PDAC in carriers of a PV in CDKN2A. This provides evidence that surveillance in such a high-risk population leads to detection of early-stage PDAC with improved resectability and survival.

Association between a 46-SNP Polygenic Risk Score and melanoma risk in Dutch patients with familial melanoma

BACKGROUND

Familial clustering of melanoma suggests a shared genetic predisposition among family members, but only 10%-40% of familial cases carry a pathogenic variant in a known high-risk melanoma susceptibility gene. We investigated whether a melanoma-specific Polygenic Risk Score (PRS) is associated with melanoma risk in patients with genetically unexplained familial melanoma.

METHODS

Dutch familial melanoma cases (n=418) were genotyped for 46 SNPs previously identified as independently associated with melanoma risk. The 46-SNP PRS was calculated and standardised to 3423 healthy controls (sPRS) and the association between PRS and melanoma risk was modelled using logistic regression. Within the case series, possible differences were further explored by investigating the PRS in relation to (1) the number of primary melanomas in a patient and (2) the extent of familial clustering of melanoma.

RESULTS

The PRS was significantly associated with melanoma risk, with a per-SD OR of 2.12 (95% CI 1.90 to 2.35, p<0.001), corresponding to a 5.70-fold increased risk (95% CI 3.93 to 8.28) when comparing the top 90th to the middle 40-60th PRS percentiles. The mean PRS was significantly higher in cases with multiple primary melanomas than in cases with a single melanoma (sPRS 1.17 vs 0.71, p=0.001). Conversely, cases from high-density melanoma families had a lower (but non-significant) mean PRS than cases from low-density families (sPRS 0.60 vs 0.94, p=0.204).

CONCLUSION

Our work underlines the significance of a PRS in determining melanoma susceptibility and encourages further exploration of the diagnostic value of a PRS in genetically unexplained melanoma families.

Genotype-phenotype correlations for pancreatic cancer risk in Dutch melanoma families with pathogenic CDKN2A variants

BACKGROUND

Pathogenic variants in the CDKN2A gene are generally associated with the development of melanoma and pancreatic ductal adenocarcinoma (PDAC), but specific genotype-phenotype correlations might exist and the extent of PDAC risk is not well established for many variants.

METHODS

Using the Dutch national familial melanoma database, we identified all families with a pathogenic CDKN2A variant and investigated the occurrence of PDAC within these families. We also estimated the standardised incidence ratio and lifetime PDAC risk for carriers of a highly prevalent variant in these families.

RESULTS

We identified 172 families in which 649 individuals carried 15 different pathogenic variants. The most prevalent variant was the founder mutation c.225_243del (p16-Leiden, 484 proven carriers). Second most prevalent was c.67G>C (55 proven carriers). PDAC developed in 95 of 163 families (58%, including 373 of 629 proven carriers) harbouring a variant with an effect on the p16INK4a protein, whereas PDAC did not occur in the 9 families (20 proven carriers) with a variant affecting only p14ARF. In the c.67G>C families, PDAC occurred in 12 of the 251 (5%) persons at risk. The standardised incidence ratio was 19.1 (95% CI 8.3 to 33.6) and the cumulative PDAC incidence at age 75 years (lifetime risk) was 19% (95% CI 7.5% to 30.1%).

CONCLUSIONS

Our results support the notion that pathogenic CDKN2A variants affecting the p16INK4a protein, including c.67G>C, are associated with increased PDAC risk and carriers of such variants should be offered pancreatic cancer surveillance. There is no clinical evidence that impairment of only the p14ARF protein leads to an increased PDAC risk.

Families with BAP1-Tumor Predisposition Syndrome in The Netherlands: Path to Identification and a Proposal for Genetic Screening Guidelines

Germline pathogenic variants in the BRCA1-associated protein-1 (BAP1) gene cause the BAP1-tumor predisposition syndrome (BAP1-TPDS, OMIM 614327). BAP1-TPDS is associated with an increased risk of developing uveal melanoma (UM), cutaneous melanoma (CM), malignant mesothelioma (MMe), renal cell carcinoma (RCC), meningioma, cholangiocarcinoma, multiple non-melanoma skin cancers, and BAP1-inactivated nevi. Because of this increased risk, it is important to identify patients with BAP1-TPDS. The associated tumors are treated by different medical disciplines, emphasizing the need for generally applicable guidelines for initiating genetic analysis. In this study, we describe the path to identification of BAP1-TPDS in 21 probands found in the Netherlands and the family history at the time of presentation. We report two cases of de novo BAP1 germline mutations (2/21, 9.5%). Findings of this study combined with previously published literature, led to a proposal of guidelines for genetic referral. We recommend genetic analysis in patients with ≥2 BAP1-TPDS-associated tumors in their medical history and/or family history. We also propose to test germline BAP1 in patients diagnosed with UM <40 years, CM <18 years, MMe <50 years, or RCC <46 years. Furthermore, other candidate susceptibility genes for tumor types associated with BAP1-TPDS are discussed, which can be included in gene panels when testing patients.

Assessing a single SNP located at TERT/CLPTM1L multi-cancer risk region as a genetic modifier for risk of pancreatic cancer and melanoma in Dutch CDKN2A mutation carriers

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 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.

Multigene panel sequencing of established and candidate melanoma susceptibility genes in a large cohort of Dutch non-CDKN2A/CDK4 melanoma families

Germline mutations in the major melanoma susceptibility gene CDKN2A explain genetic predisposition in only 10–40% of melanoma‐prone families. In our study we comprehensively characterized 488 melanoma cases from 451 non‐CDKN2A/CDK4 families for mutations in 30 established and candidate melanoma susceptibility genes using a custom‐designed targeted gene panel approach. We identified (likely) pathogenic variants in established melanoma susceptibility genes in 18 families (n = 3 BAP1, n = 15 MITF p.E318K; diagnostic yield 4.0%). Among the three identified BAP1‐families, there were no reported diagnoses of uveal melanoma or malignant mesothelioma. We additionally identified two potentially deleterious missense variants in the telomere maintenance genes ACD and TERF2IP, but none in the POT1 gene. MC1R risk variants were strongly enriched in our familial melanoma cohort compared to healthy controls (R variants: OR 3.67, 95% CI 2.88–4.68, p <0.001). Several variants of interest were also identified in candidate melanoma susceptibility genes, in particular rare (pathogenic) variants in the albinism gene OCA2 were repeatedly found. We conclude that multigene panel testing for familial melanoma is appropriate considering the additional 4% diagnostic yield in non‐CDKN2A/CDK4 families. Our study shows that BAP1 and MITF are important genes to be included in such a diagnostic test.

What's new?

Germline mutations in CDKN2A are major contributors to familial melanoma. These mutations, however, are responsible for only 10 to 40 percent of genetic susceptibility in melanoma‐prone families. In this study, 30 established and candidate melanoma susceptibility genes were investigated for associations with the disease in patients from 451 non‐CDKN2A/CDK4 melanoma families. From the candidate gene panel, (likely) pathogenic variants in BAP1 and MITF were identified in several families, and potentially deleterious variants were identified in the shelterin complex genes ACD and TERF2IP. These genes appear to play a significant role in familial melanoma predisposition and are therefore promising candidates for incorporation into comprehensive genetic tests.

CM-Score: a validated scoring system to predict CDKN2A germline mutations in melanoma families from Northern Europe

BACKGROUND

Several factors have been reported that influence the probability of a germline CDKN2A mutation in a melanoma family. Our goal was to create a scoring system to estimate this probability, based on a set of clinical features present in the patient and his or her family.

METHODS

Five clinical features and their association with CDKN2A mutations were investigated in a training cohort of 1227 Dutch melanoma families (13.7% with CDKN2A mutation) using multivariate logistic regression. Predefined features included number of family members with melanoma and with multiple primary melanomas, median age at diagnosis and presence of pancreatic cancer or upper airway cancer in a family member. Based on these five features, a scoring system (CDKN2A Mutation(CM)-Score) was developed and subsequently validated in a combined Swedish and Dutch familial melanoma cohort (n=421 families; 9.0% with CDKN2A mutation).

RESULTS

All five features were significantly associated (p<0.05) with a CDKN2A mutation. At a CM-Score of 16 out of 49 possible points, the threshold of 10% mutation probability is approximated (9.9%; 95% CI 9.8 to 10.1). This probability further increased to >90% for families with ≥36 points. A CM-Score under 16 points was associated with a low mutation probability (≤4%). CM-Score performed well in both the training cohort (area under the curve (AUC) 0.89; 95% CI 0.86 to 0.92) and the external validation cohort (AUC 0.94; 95% CI 0.90 to 0.98).

CONCLUSION

We developed a practical scoring system to predict CDKN2A mutation status among melanoma-prone families. We suggest that CDKN2A analysis should be recommended to families with a CM-Score of ≥16 points.

Constitutional mismatch repair deficiency in a healthy child: On the spot diagnosis?

Constitutional mismatch repair deficiency (CMMRD) is a rare, recessively inherited childhood cancer predisposition syndrome caused by biallelic germline mutations in one of the mismatch repair genes. The CMMRD phenotype overlaps with that of neurofibromatosis type 1 (NF1), since many patients have multiple café-au-lait macules (CALM) and other NF1 signs, but no germline NF1 mutations. We report of a case of a healthy 6-year-old girl who fulfilled the diagnostic criteria of NF1 with >6 CALM and freckling. Since molecular genetic testing was unable to confirm the diagnosis of NF1 or Legius syndrome and the patient was a child of consanguineous parents, we suspected CMMRD and found a homozygous PMS2 mutation that impairs MMR function. Current guidelines advise testing for CMMRD only in cancer patients. However, this case illustrates that including CMMRD in the differential diagnosis in suspected sporadic NF1 without causative NF1 or SPRED1 mutations may facilitate identification of CMMRD prior to cancer development. We discuss the advantages and potential risks of this CMMRD testing scenario.

Targeted next-generation sequencing of FNA-derived DNA in pancreatic cancer

To improve the diagnostic value of fine-needle aspiration (FNA)-derived material, we perform targeted next-generation sequencing (NGS) in patients with a suspect lesion of the pancreas. The NGS analysis can lead to a change in the treatment plan or supports inconclusive or uncertain cytology results. We describe the advantages of NGS using one particular patient with a recurrent pancreatic lesion 7 years after resection of a pancreatic ductal adenocarcinoma (PDAC). Our NGS analysis revealed the presence of a presumed second primary cancer in the pancreatic remnant, which led to a change in treatment: resection with curative intend instead of palliation. Additionally, NGS identified an unexpected germline CDKN2A 19-base pair deletion, which predisposed the patient to developing PDAC. Preoperative NGS analysis of FNA-derived DNA can help identify patients at risk for developing PDAC and define future therapeutic options.

Application of a Serum Protein Signature for Pancreatic Cancer to Separate Cases from Controls in a Pancreatic Surveillance Cohort

BACKGROUND

Pancreatic cancer (PC) surveillance is currently offered to individuals with a genetic predisposition to PC, but routinely used radiological screening modalities are not entirely reliable in detecting early-stage PC or its precursor lesions. We recently identified a discriminating PC biomarker signature in a sporadic patient cohort. In this study, we investigated if protein profiling can accurately distinguish PC from non-PC in a pancreatic surveillance cohort of genetically predisposed individuals.

METHODS

Serum samples of 66 individuals with a CDKN2A germline mutation who participated in the pancreatic surveillance program (5 cases, 61 controls) were obtained following a standardized protocol. After sample clean-up, peptide and protein profiles were obtained on an ultrahigh-resolution matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry platform. A discriminant score for each sample was calculated with a previously designed prediction rule, and the median discriminant scores of cases and controls were compared. Individuals with precursor lesions of PC (n = 4) and individuals with a recent diagnosis of melanoma (n = 4) were also separately considered.

RESULTS

Cases had a higher median discriminant score than controls (0.26 vs 0.016; P = .001). The only individual with pathologically confirmed precursor lesions of PC could also be clearly distinguished from controls, and having a (recent) medical history of melanoma did not influence the protein signatures.

CONCLUSIONS

Peptide and protein signatures are able to accurately distinguish PC cases from controls in a pancreatic surveillance setting. Mass spectrometry-based protein profiling therefore seems to be a promising candidate for implementation in the pancreatic surveillance program as an additional screening modality.

Loss-of-Function Mutations in the Cell-Cycle Control Gene CDKN2A Impact on Glucose Homeostasis in Humans

At the CDKN2A/B locus, three independent signals for type 2 diabetes risk are located in a noncoding region near CDKN2A. The disease-associated alleles have been implicated in reduced β-cell function, but the underlying mechanism remains elusive. In mice, β-cell-specific loss of Cdkn2a causes hyperplasia, while overexpression leads to diabetes, highlighting CDKN2A as a candidate effector transcript. Rare CDKN2A loss-of-function mutations are a cause of familial melanoma and offer the opportunity to determine the impact of CDKN2A haploinsufficiency on glucose homeostasis in humans. To test the hypothesis that such individuals have improved β-cell function, we performed oral and intravenous glucose tolerance tests on mutation carriers and matched control subjects. Compared with control subjects, carriers displayed increased insulin secretion, impaired insulin sensitivity, and reduced hepatic insulin clearance. These results are consistent with a model whereby CDKN2A loss affects a range of different tissues, including pancreatic β-cells and liver. To test for direct effects of CDKN2A-loss on β-cell function, we performed knockdown in a human β-cell line, EndoC-bH1. This revealed increased insulin secretion independent of proliferation. Overall, we demonstrated that CDKN2A is an important regulator of glucose homeostasis in humans, thus supporting its candidacy as an effector transcript for type 2 diabetes-associated alleles in the region.

Pancreatic cancer-associated gene polymorphisms in a nation-wide cohort of p16-Leiden germline mutation carriers; a case-control study

Background

The p16-Leiden founder mutation in the CDKN2A gene is the most common cause of Familial Atypical Multiple Mole Melanoma (FAMMM) syndrome in the Netherlands. Individuals with this mutation are at increased risk for developing melanoma of the skin, as well as pancreatic cancer. However, there is a notable interfamilial variability in the occurrence of pancreatic cancer among p16-Leiden families. We aimed to test whether previously identified genetic risk factors for pancreatic cancer modify the risk for pancreatic cancer in p16-Leiden germline mutation carriers.

Methods

Seven pancreatic cancer-associated SNPs were selected from the literature and were genotyped in a cohort of 185 p16-Leiden germline mutation carriers from 88 families, including 50 cases (median age 55 years) with pancreatic cancer and 135 controls (median age 64 years) without pancreatic cancer. Allelic odds ratios per SNP were calculated.

Results

No significant association with pancreatic cancer was found for any of the seven SNPs.

Conclusions

Since genetic modifiers for developing melanoma have already been identified in CDKN2A mutation carriers, this study does not exclude that genetic modifiers do not play a role in the individual pancreatic cancer risk in this cohort of p16-Leiden germline mutation carriers. The search for these modifiers should therefore continue, because they can potentially facilitate more targeted pancreatic surveillance programs.

Variation in precursor lesions of pancreatic cancer among high-risk groups

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) surveillance programs are currently offered to high-risk individuals aiming to detect precursor lesions or PDAC at an early stage. We assessed differences in frequency and behavior of precursor lesions and PDAC between two high-risk groups.

EXPERIMENTAL DESIGN

Individuals with a p16-Leiden germline mutation (N = 116; median age 54 years) and individuals from familial pancreatic cancer (FPC) families (N = 125; median age 47 years) were offered annual surveillance by MRI and magnetic resonance cholangiopancreatography (MRCP) with or without endoscopic ultrasound (EUS) for a median surveillance period of 34 months (0-127 months) or 36 months (0-110 months), respectively. Detailed information was collected on pancreatic cystic lesions detected on MRCP and precursor lesions in surgical specimens of patients who underwent pancreatic surgery.

RESULTS

Cystic lesions were more common in the FPC cohort (42% vs. 16% in p16-Leiden cohort), whereas PDAC was more common in the p16-Leiden cohort (7% vs. 0.8% in FPC cohort). Intraductal papillary mucinous neoplasm (IPMN) was a common finding in surgical specimens of FPC-individuals, and was only found in two patients of the p16-Leiden cohort. In the p16-Leiden cohort, a substantial proportion of cystic lesions showed growth or malignant transformation during follow-up, whereas in FPC individuals most cystic lesions remain stable.

CONCLUSION

In p16-Leiden mutation carriers, cystic lesions have a higher malignant potential than in FPC-individuals. On the basis of these findings, a more intensive surveillance program may be considered in this high-risk group.

Variation in precursor lesions of pancreatic cancer among high-risk groups

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) surveillance programs are currently offered to high-risk individuals aiming to detect precursor lesions or PDAC at an early stage. We assessed differences in frequency and behavior of precursor lesions and PDAC between two high-risk groups.

EXPERIMENTAL DESIGN

Individuals with a p16-Leiden germline mutation (N = 116; median age 54 years) and individuals from familial pancreatic cancer (FPC) families (N = 125; median age 47 years) were offered annual surveillance by MRI and magnetic resonance cholangiopancreatography (MRCP) with or without endoscopic ultrasound (EUS) for a median surveillance period of 34 months (0-127 months) or 36 months (0-110 months), respectively. Detailed information was collected on pancreatic cystic lesions detected on MRCP and precursor lesions in surgical specimens of patients who underwent pancreatic surgery.

RESULTS

Cystic lesions were more common in the FPC cohort (42% vs. 16% in p16-Leiden cohort), whereas PDAC was more common in the p16-Leiden cohort (7% vs. 0.8% in FPC cohort). Intraductal papillary mucinous neoplasm (IPMN) was a common finding in surgical specimens of FPC-individuals, and was only found in two patients of the p16-Leiden cohort. In the p16-Leiden cohort, a substantial proportion of cystic lesions showed growth or malignant transformation during follow-up, whereas in FPC individuals most cystic lesions remain stable.

CONCLUSION

In p16-Leiden mutation carriers, cystic lesions have a higher malignant potential than in FPC-individuals. On the basis of these findings, a more intensive surveillance program may be considered in this high-risk group.