Familial Pancreatic Cancer and the Future of Directed Screening

Incidence and risk factors of pancreatic cancer during 15 years follow-up in the Golestan Cohort Study in Iran

BACKGROUND

Cancer is one of the main causes of death in the worldwide. Pancreatic Cancer (PC) is prevalent in developed and increasing in developing countries. PC is important because of its low survival rate, high fatality, and increasing incidence. Therefore, identifying risk factors to prevent its development is necessary. This study aimed to determine incidence of PC and its risk factors in the Golestan Cohort Study (GCS) in Iran.

METHOD

This study is a prospective population-based cohort study in the frame of GCS with 15 years of follow-up for PC. GCS was launched in the Golestan province of Iran with 50045 participants who were 40 to 75 years old. variables included: age, gender, education status, smoking, alcohol consumption, opium usage, type of blood group, dyslipidemia, body mass index (BMI), waist circumference (WC), family history (FH) of PC, ethnicity, and history of diabetes mellitus (DM).

RESULT

Among 50045 participants of GCS during 15 years of follow up, 100 people were diagnosed PC. PC incidence was 0.2%. Age-standardized incidence rate (ASR) of PC in the study population was 11.12 per 100,000 person-years. People with age ≥60 years were 46, in 50-59 years old group were 36, and 18 of them were <50 years (p<0.001). The smoking rate in PC group was 27% (p<0.01). Univariate model of cox regression analysis showed age 50-59, ≥60 years compared to <50 years [HR:3.006, 95%CI (1.707-5.294), p<0.001], [HR: 6.727, 95% CI (3.899-11.608), p<0.001], male gender [HR:1.541, 95%CI (1.041-2.281), p = 0.031], opium use [HR:1.436, 95% CI (0.887-2.324), p = 0.141], and smoking [HR:1.884, 95%CI (1.211-2.929), p = 0.005] were predictors for PC. In the multivariate model after adjusting, age 50-59 [HR:2.99, 95% CI (1.698-5.265), p<0.001], and ≥60 years [HR: 6.564, 95% CI (3.797-11.346), p<0.001] was the only predictor for PC.

CONCLUSION

This study revealed an incidence of PC 0.2% in GCS in Iran. Main risk factor for PC was older age.

Using Fuzzy Mathematical Model in the Differential Diagnosis of Pancreatic Lesions Using Ultrasonography and Echographic Texture Analysis

Malignant tumors of the pancreas are the fourth leading cause of cancer-related deaths. This is mainly because they are often diagnosed at a late stage. One of the challenges in diagnosing focal lesions in the pancreas is the difficulty in distinguishing them from other conditions due to the unique location and anatomy of the organ, as well as the similarity in their ultrasound characteristics. One of the most sensitive imaging modalities of the pancreas is endoscopic ultrasonography. However, clinicians recognize that EUS is a difficult and highly operator-dependent method, while its results are highly dependent on the experience of the investigator. Hybrid technologies based on artificial intelligence methods can improve the accuracy and objectify the results of endosonographic diagnostics. Endoscopic ultrasonography was performed on 272 patients with focal lesions of the pancreatobiliary zone, who had been treated in the surgical section of the Kursk Regional Clinical Hospital in 2014-2023. The study utilized an Olympus EVIS EXERA II video information endoscopic system, along with an EU-ME1 ultrasound unit equipped with GF UM160 and GF UC140P-AL5 echo endoscopes. Out of the focal formations in the pancreatobiliary zone, pancreatic cancer was detected in 109 patients, accounting for 40.1% of the cases. Additionally, 40 patients (14.7%) were diagnosed with local forms of chronic pancreatitis. The reference sonograms displayed distinguishable focal pancreatic pathologies, leading to the development of hybrid fuzzy mathematical decision-making rules at the South-West State University in Kursk, Russian Federation. This research resulted in the creation of a fuzzy hybrid model for the differential diagnosis of chronic focal pancreatitis and pancreatic cancer. Endoscopic ultrasonography, combined with hybrid fuzzy logic methodology, has made it possible to create a model for differentiating between chronic focal pancreatitis and pancreatic ductal adenocarcinoma. Statistical testing on control samples has shown that the diagnostic model, based on reference endosonograms of the echographic texture of pancreatic focal pathology, has a confidence level of 0.6 for the desired diagnosis. By incorporating additional information about the contours of focal formations obtained through endosonography, the reliability of the diagnosis can be increased to 0.9. This level of reliability is considered acceptable in clinical practice and allows for the use of the developed model, even with data that is not well-structured.

Pancreatic Cancer Surveillance in Carriers of a Germline Pathogenic Variant in CDKN2A

Three percent of patients with pancreatic ductal adenocarcinoma (PDAC) present a germline pathogenic variant (GPV) associated with an increased risk of this tumor, CDKN2A being one of the genes associated with the highest risk. There is no clear consensus on the recommendations for surveillance in CDKN2A GPV carriers, although the latest guidelines from the International Cancer of the Pancreas Screening Consortium recommend annual endoscopic ultrasound (EUS) or magnetic resonance imaging (MRI) regardless of family history. Our aim is to describe the findings of the PDAC surveillance program in a cohort of healthy CDKN2A GPV heterozygotes. This is an observational analysis of prospectively collected data from all CDKN2A carriers who underwent screening for PDAC at the high-risk digestive cancer clinic of the “Hospital Clínic de Barcelona” between 2013 and 2021. A total of 78 subjects were included. EUS or MRI was performed annually with a median follow-up of 66 months. Up to 17 pancreatic findings were described in 16 (20.5%) individuals under surveillance, although most of them were benign. No significant precursor lesions were identified, but an early PDAC was detected and treated. While better preventive strategies are developed, we believe that annual surveillance with EUS and/or MRI in CDKN2A GPV heterozygotes may be beneficial.

Genetic Testing Among Patients with High-Risk Breast, Ovarian, Pancreatic, and Prostate Cancers

BACKGROUND

The National Comprehensive Cancer Network recommends genetic testing in patients with potentially hereditary breast, ovarian, pancreatic, and prostate cancers (HBOPP). Knowledge of genetic mutations impacts decisions about screening and treatment.

METHODS

A retrospective cohort study of 28,586 HBOPP patients diagnosed from 2013 to 2019 was conducted using a linked administrative-cancer database in the Seattle-Puget Sound SEER area. Guideline-concordant testing (GCT) was assessed annually according to guideline updates. Frequency of testing according to patient/cancer characteristics was evaluated using chi-squared tests, and factors associated with receipt of genetic testing were identified using multivariable logistic regression.

RESULTS

Testing occurred in 17% of HBOPP patients, increasing from 9% in 2013 to 21% in 2019 (p < 0.001). Ovarian cancer had the highest testing (40%) and prostate cancer the lowest (4%). Age < 50, female sex, non-Hispanic White race, commercial insurance, urban location, family history of HBOPP, and triple negative breast cancer (TNBC) were associated with increased testing (all p < 0.05). GCT increased from 38% in 2013 to 44% in 2019, and was highest for early age at breast cancer diagnosis, TNBC, male breast cancer, and breast cancer with family history of HBOPP (all > 70% in 2019), and lowest for metastatic prostate cancer (6%).

CONCLUSIONS

The frequency of genetic testing for HBOPP cancer has increased over time. Though GCT is high for breast cancer, there are gaps in concordance among patients with other cancers. Increasing provider and patient education, genetic counseling, and insurance coverage for testing among HBOPP patients may improve guideline adherence.

Differential Diagnosis of Pancreatic Cancer and Chronic Pancreatitis According to Endoscopic Ultrasonography Based on the Analysis of the Nature of the Contours of Focal Formations Based on Fuzzy Mathematical Models

One of the key echographic signs of focal pathology of the pancreas is the presence of formation contours and their nature. Endoscopic ultrasonography has a unique ability to visualize the echographic texture of the pancreatic parenchyma, and also allows you to assess in detail the boundaries and nature of the contours of the tumor formations of the organ due to the proximity of the ultrasound sensor. However, the differential diagnosis of focal pancreatic lesions remains a difficult clinical task due to the similarity of their echosemiotics. One of the ways to objectify and improve the accuracy of ultrasound data is the use of artificial intelligence methods for interpreting images. Improving the quality of differential diagnosis of focal pathology of the pancreas according to endoscopic ultrasonography based on the analysis of the nature of the contours of focal formations using fuzzy mathematical models.

Clinical Significance of Germline Pathogenic Variants among 51 Cancer Predisposition Genes in an Unselected Cohort of Italian Pancreatic Cancer Patients

Multigene germline panel testing is recommended for Pancreatic Cancer (PC) patients; however, for non-BRCA1/2 genes, the clinical utility is unclear. A comprehensive multi-gene assessment in unselected Italian PC patients is missing. We evaluated the prevalence and impact of Pathogenic Variants (PV) in 51 PC susceptibility genes in a real-world series of 422 Italian PC patients unselected for Family History (FH), compared the clinical characteristics and conducted survival analyses. 17% of patients had PVs (70/422), mainly in BRCA1/2 (4.5%, all <70 y), CDKN2A (4.5%, all >50 y), ATM (2.1%). PV carriers were younger (64 vs. 67; p = 0.02) and had more frequent personal/FH of PC, melanoma and breast/ovarian cancer (all p < 0.05). The Overall Survival (OS) was longer in patients carrying PVs (HR 0.78; p = 0.090), comprising ATM carriers (HR 0.33; p = 0.054). In the oxaliplatin-treated subset, PV carriers showed better control of the disease, although this was not statistically significant (67% vs. 56%). CDKN2A, BRCA2 and ATM were the most frequently altered genes. ATM PVs were positively associated with OS in 41% of PV carriers, 60% of whom carried CDKN2A,BRCA2 or ATM PVs, had negative FH and would have been missed by traditional referral. Thus, CDKN2A and ATM should be added to BRCA1/2 testing regardless of FH.

ZNF488 Promotes the Invasion and Migration of Pancreatic Carcinoma Cells through the Akt/mTOR Pathway

OBJECTIVE

Studies have demonstrated that zinc finger protein 488 (ZNF488) is highly expressed in pancreatic carcinoma (PC), but its effect on PC and its molecular mechanism remains unclear.

METHODS

Real-time fluorescent quantitative PCR (RT-qPCR) was employed to detect the ZNF488 expression in PC patients' cancer tissues and cell lines. After interfering with or overexpressing ZNF488 in PANC-1 and AsPC-1 cells, respectively, the CCK-8, cell cloning, Transwell, and scratch assays were performed to detect cell proliferation, cell viability, invasion ability, and migration ability. In addition, Western blot was applied to assess the protein expression of Akt, p-Akt, mTOR, and p-mTOR in the Akt-mTOR pathway.

RESULTS

The ZNF488 expression was evidently raised in PC tissues and cell lines, and the starBase V3.0 database indicated that the higher the ZNF488 expression, the lower the survival rate of PC patients. Furthermore, we discovered that overexpressing ZNF488 can markedly promote the proliferation, invasion, and migration of PC cells. At the same time, highly expressed ZNF488 distinctly increased the p-Akt and p-mTOR expressions and the p-Akt/Akt and p-mTOR/mTOR ratios. However, after knocking down the ZNF488 expression, it had the opposite results. In addition, the Akt agonist SC79 can alleviate the effect of ZNF488 knockdown on Akt/mTOR pathway-related proteins, while Akt inhibitor AZD5363 had the opposite effect.

CONCLUSION

ZNF488 could promote the proliferation, invasion, and migration of PC cells, and its mechanism may be related to the activation of the Akt/mTOR pathway. This study demonstrated that ZNF488 could be used as a molecular target for diagnosing and treating PC.

Genetic Variants in Patients With a Family History of Pancreatic Cancer: Impact of Multigene Panel Testing

OBJECTIVES

Up to 15% of pancreatic cancer is hereditary. We aim to study the prevalence of pathogenic germline variants (PGVs) in patients referred for genetic counseling with a family history (FH) of pancreatic cancer.

METHODS

We performed a retrospective single institution cohort study of individuals who underwent cancer genetic counseling with a FH of pancreatic cancer.

RESULTS

We identified 314 patients. Genetic testing was performed in 291 (92.7%) and 187 (59.6%) underwent expanded multigene panel testing. Fifty-four PGVs were found in 53 (16.9%) individuals; PGVs in BRCA1/2 (37%) were most common. Seventy-two variants of uncertain significance (VUS) were found in 58 (18.5%) individuals; VUS in ATM (16.7%) were the most common. Of the 112 (35.4%) with a first-degree family member with pancreatic cancer, 14 PGVs were identified in 14 (12.5%) individuals and 28 VUS were identified in 21 (18.8%) individuals. After genetic testing, 47 (15.0%) individuals met International Cancer of the Pancreas Screening criteria and 67 (21.3%) met American College of Gastroenterology criteria for pancreatic surveillance.

CONCLUSIONS

Genetic testing of individuals with a FH of pancreatic cancer represents an opportunity to identify individuals who may be candidates for pancreatic surveillance.

BRCA in Gastrointestinal Cancers: Current Treatments and Future Perspectives

A strong association between pancreatic cancer and BRCA1 and BRCA2 mutations is documented. Based on promising results of breast and ovarian cancers, several clinical trials with poly (ADP-ribose) polymerase inhibitors (PARPi) are ongoing for gastrointestinal (GI) malignancies, especially for pancreatic cancer. Indeed, the POLO trial results provide promising and awaited changes for the pancreatic cancer therapeutic landscape. Contrariwise, for other gastrointestinal tumors, the rationale is currently only alleged. The role of BRCA mutation in gastrointestinal cancers is the subject of this review. In particular, we aim to provide the latest updates about novel therapeutic strategies that, exploiting DNA repair defects, promise to shape the future therapeutic scenario of GI cancers.

Gene Signature and Identification of Clinical Trait-Related m6 A Regulators in Pancreatic Cancer

Pancreatic cancer (PC) has a very poor prognosis and is usually diagnosed only at an advanced stage. The discovery of new biomarkers for PC will help in early diagnosis and a better prognosis for patients. Recently, N6-methyladenosine (m⁶A) RNA modifications and their regulators have been implicated in the development of many cancers. To investigate the functions and mechanisms of m⁶A modifications in the development of PC, 19 m⁶A regulators, including m⁶A-methyltransferases (ZC3H13, RBM15/15B, WTAP, KIAA1429, and METTL3/14), demethylases (FTO and ALKBH5), and binding proteins (YTHDF1/2/3, YTHDC1/2, IGF2BP1/2/3, HNRNPC, and HNRNPA2B1) were analyzed in 178 PC tissues from the cancer genome atlas (TCGA) database. The results were verified in PC cell lines Mia-PaCa-2, BXPC-3, and the control cell line HDE-CT. The m⁶A regulators-based sample clusters were significantly related to overall survival (OS). Further, lasso regression identified a six-m⁶A-regulator-signature prognostic model (KIAA1429, HNRNPC, METTL3, YTHDF1, IGF2BP2, and IGF2BP3). Model-based high-risk and low-risk groups were significantly correlated with OS and clinical traits (pathologic M, N, and clinical stages and vital status). The risk signature was verified as an independent prognostic marker for patients with PC. Finally, gene set enrichment analysis revealed m⁶A regulators (KIAA1429, HNRNPC, and IGF2BP2) were related to multiple biological behaviors in PC, including adipocytokine signaling, the well vs. poorly differentiated tumor pathway, tumor metastasis pathway, epithelial mesenchymal transition pathway, gemcitabine resistance pathway, and stemness pathway. In summary, the m6A regulatory factors which related to clinical characteristics can be involved in the malignant progression of PC, and the constructed risk markers may be a promising prognostic biomarker that can guide the individualized treatment of PC patients.

MiR-487a-3p suppresses the malignant development of pancreatic cancer by targeting SMAD7

OBJECTIVE

To uncover the role of microRNA-487a-3p (miR-487a-3p) in influencing the malignant development of pancreatic cancer and the involvement of its downstream target SMAD7.

METHODS

MiR-487a-3p level in 40 pancreatic cancer and paracancerous tissues was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between miR-487a-3p level and clinical indicators in pancreatic cancer patients was analyzed. Regulatory effects of miR-487a-3p on biological phenotypes of pancreatic cancer cells were assessed. At last, the involvement of miR-487a-3p and its downstream target SMAD7 in pancreatic cancer was determined.

RESULTS

MiR-487a-3p was lowly expressed in pancreatic cancer tissues. Pancreatic cancer patients expressing a low level of miR-487a-3p suffered high metastasis rate and poor prognosis. Overexpression of miR-487a-3p markedly attenuated proliferative and migratory capacities in pancreatic cancer cells. SMAD7 was the downstream target of miR-487a-3p, which was highly expressed in pancreatic cancer samples. Overexpression of SMAD7 reversed the regulatory effects of miR-487a-3p on pancreatic cancer cell phenotypes.

CONCLUSIONS

MiR-487a-3p is downregulated in pancreatic cancer samples, which is linked to metastasis and prognosis in pancreatic cancer. It inhibits the malignant development of pancreatic cancer by negatively regulating SMAD7.

Technological advances for the detection of melanoma: Advances in molecular techniques

The growth of molecular technologies analyzing skin cells and inherited genetic variations has the potential to address current gaps in both diagnostic accuracy and prognostication in patients with melanoma or in individuals who are at risk for developing melanoma. In the second article in this continuing medical education series, novel molecular technologies are reviewed. These have been developed as adjunct tools for melanoma management and include the Pigmented Lesion Assay, myPath Melanoma, and DecisionDx-Melanoma tests, and genetic testing in patients with a strong familial melanoma history. These tests are commercially available and marketed as ancillary tools for clinical decision-making, diagnosis, and prognosis. We review fundamental principles behind each test, discuss peer-reviewed literature assessing their performance, and highlight the utility and limitations of each assay. The goal of this article is to provide a comprehensive, evidence-based foundation for clinicians regarding the management of patients with difficult pigmented lesions.

Health Care Provider Perceptions of Caring for Individuals with Inherited Pancreatic Cancer Risk

Recent national guidelines recommend genetic risk assessment for all patients diagnosed with pancreatic cancer, yet individuals with pancreatic cancer obtain genetic testing at suboptimal rates. Both patient and provider factors play a role in adherence to genetic testing recommendations. The purpose of this study was to understand health care provider perspectives of caring for patients with inherited pancreatic cancer risk. The study was a cross-sectional mixed method study utilizing a qualitative interview and a survey. The study sample included health care providers who provide care for patients with pancreatic cancer or inherited risk. Qualitative data were analyzed using content analysis, while quantitative data were summarized using descriptive statistics. Thirty participants had complete interview data and 29 completed a survey. The sample was comprised of physicians (n = 17), genetic counselors (n = 6), nurses (n = 3), and social workers (n = 3). Respondents were less confident in their ability to identify patients with inherited pancreatic cancer risk compared with other hereditary cancer syndromes. Several challenges were identified including the pancreatic cancer illness trajectory; lack of evidence-based practice guidelines; difficulty interpreting genetic test results; and difficulty following up on referrals. Participants perceived a lack of educational resources for patients with inherited pancreatic cancer risk. Health care providers who care for individuals with inherited pancreatic cancer risk face challenges that are distinct from those encountered during the care of individuals for other hereditary cancers. There is a need for additional resources at the patient-, provider-, and system-level.

Genomic Features and Clinical Management of Patients with Hereditary Pancreatic Cancer Syndromes and Familial Pancreatic Cancer

Pancreatic cancer (PC) is one of the most devastating malignancies; it has a 5-year survival rate of only 9%, and novel treatment strategies are urgently needed. While most PC cases occur sporadically, PC associated with hereditary syndromes or familial PC (FPC; defined as an individual having two or more first-degree relatives diagnosed with PC) accounts for about 10% of cases. Hereditary cancer syndromes associated with increased risk for PC include Peutz-Jeghers syndrome, hereditary pancreatitis, familial atypical multiple mole melanoma, familial adenomatous polyposis, Lynch syndrome and hereditary breast and ovarian cancer syndrome. Next-generation sequencing of FPC patients has uncovered new susceptibility genes such as PALB2 and ATM, which participate in homologous recombination repair, and further investigations are in progress. Previous studies have demonstrated that some sporadic cases that do not fulfil FPC criteria also harbor similar mutations, and so genomic testing based on family history might overlook some susceptibility gene carriers. There are no established screening procedures for high-risk unaffected cases, and it is not clear whether surveillance programs would have clinical benefits. In terms of treatment, poly (ADP-ribose) polymerase inhibitors for BRCA-mutated cases or immune checkpoint inhibitors for mismatch repair deficient cases are promising, and clinical trials of these agents are underway.

Familial Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC), although a rare disease, has a poor prognosis. With 5-year overall survival of 8%, there is a critical need to detect PDAC early or at a premalignant stage. Current screening methods are largely imaging based, but a more focused screening approach based on modifiable and nonmodifiable risk factors may improve the efficacy and likely outcomes of screening. In addition, the pathologic mechanisms that lead to the development of PDAC are discussed in an effort to further understand the targets of pancreatic cancer screening. The focus of this article will be inherited pancreatic cancer syndromes and familial pancreatic cancer, which together compose up to 10% of PDAC. Understanding the methods and targets of PDAC screening in high-risk individuals may translate to improved morbidity and mortality.

Incidence of Pathogenic Variants in Those With a Family History of Pancreatic Cancer

Discovery of a hereditary cancer syndrome can be one of the factors that determine whether a healthy individual completes pancreas cancer screening or whether an individual with cancer receives certain chemotherapies. Retrospective review was completed to determine the likelihood of detection of a pathogenic variant causing a hereditary cancer syndrome based on personal and family history. Study was completed through the hereditary cancer clinic at Mayo Clinic Florida over a 6 year period, 1/2012 through 1/2018. All participants were referred based on suspicion for a hereditary cancer syndrome based on personal and/or family history. Patients' personal oncologic history at time of consultation was recorded, as well as, cancer diagnoses in the family history and the number of family members with a history of pancreas cancer. Test result and gene name, if variant was pathogenic or likely pathogenic, were noted as well. A total of 2,019 patients completed genetic testing during study period. Personal history of cancer included a variety of primaries, including breast (N = 986), ovarian (N = 119), colon (N = 106), prostate (N = 65), and pancreas (N = 59). A positive result was discovered in 11% of the total group. Two hundred and eighty five reported a family history of pancreas cancer. The incidence of pathogenic variants was 13% (37/285) in those with any family history and 23% (13/56) in those with two or more relatives with pancreatic cancer. Those with multiple relatives with pancreatic cancer were significantly more likely to carry a pathogenic variant than those with a personal history of breast cancer under the age of 45 (23.2 vs. 11.9%, p = 0.02). Presence of multiple family members with a reported history of pancreatic cancer significantly increased the likelihood that a pathogenic variant would be identified in the patient even over other significant risk factors, like personal history of early onset breast cancer.

Advances in oncolytic adenovirus therapy for pancreatic cancer

Survival rates for pancreatic cancer patients have remained unchanged for the last four decades. The most aggressive, and most common, type of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), which has the lowest 5-year survival rate of all cancers globally. The poor prognosis is typically due to late presentation of often non-specific symptoms and rapid development of resistance to all current therapeutics, including the standard-of-care cytotoxic drug gemcitabine. While early surgical intervention can significantly prolong patient survival, there are few treatment options for late-stage non-resectable metastatic disease, resulting in mostly palliative care. In addition, a defining feature of pancreatic cancer is the immunosuppressive and impenetrable desmoplastic stroma that blocks access to tumour cells by therapeutic drugs. The limited effectiveness of conventional chemotherapeutics reveals an urgent need to develop novel therapies with different mechanisms of action for this malignancy. An emerging alternative to current therapeutics is oncolytic adenoviruses; these engineered biological agents have proven efficacy and tumour-selectivity in preclinical pancreatic cancer models, including models of drug-resistant cancer. Safety of oncolytic adenoviral mutants has been extensively assessed in clinical trials with only limited toxicity to normal healthy tissue being reported. Promising efficacy in combination with gemcitabine was demonstrated in preclinical and clinical studies. A recent surge in novel adenoviral mutants entering clinical trials for pancreatic cancer indicates improved efficacy through activation of the host anti-tumour responses. The potential for adenoviruses to synergise with chemotherapeutics, activate anti-tumour immune responses, and contribute to stromal dissemination render these mutants highly attractive candidates for improved patient outcomes. Currently, momentum is gathering towards the development of systemically-deliverable mutants that are able to overcome anti-viral host immune responses, erythrocyte binding and hepatic uptake, to promote elimination of primary and metastatic lesions. This review will cover the key components of pancreatic cancer oncogenesis; novel oncolytic adenoviruses; clinical trials; and the current progress in overcoming the challenges of systemic delivery.

A Sub-Type of Familial Pancreatic Cancer: Evidence and Implications of Loss-of-Function Polymorphisms in Indoleamine-2,3-Dioxygenase-2

BACKGROUND

Variation in an individual’s genetic status can impact the development of pancreatic ductal adenocarcinoma; however, the m ajority of familial pancreatic cancers (FPC) cannot yet be attributed to a specific inherited mutation. We present data suggesting a correlation between loss-of-function single nucleotide polymorphisms (SNPs) in an immune regulator gene, indoleamine-2,3-dioxygenase-2 (IDO2), and an increased risk of FPC.

STUDY DESIGN

Germline DNA from patients who underwent resection for pancreatic ductal adenocarcinoma (n = 79) was sequenced for the IDO2 SNPs R248W and Y359Stop. Genotypes resulting in inactivation of IDO2 (Y325X homozygous, R248W homozygous) were labeled as homozygous, and the other genotypes were grouped as wild-type or heterozygous. Genotype distributions of each SNP were analyzed for Hardy-Weinberg deviation. A genotype frequency set from the 1000 Genomes Project (n = 99) was used as a genetic control for genotype distribution comparisons.

RESULTS

A significant 2-fold increase in the overall prevalence of the Y359Stop homozygous genotype compared with the expected Hardy-Weinberg equilibrium was noted (p < 0.05). Familial pancreatic cancer was noted in 15 cases (19%) and comparison of the FPC cohort set to the genetic control set showed a 3-fold increase in Y359Stop homozygous rates (p = 0.054). Overall in our cohort, the homozygous genotype group was associated with increased risk of FPC (odds ratio 5.4; 95% CI 1.6 to 17.6; p < 0.01). Sex, age at diagnosis, and history of tobacco use were not found to be significantly associated with FPC.

CONCLUSIONS

Our preliminary data suggest a strong association between the IDO2 inactivating Y359Stop SNP and an increased risk of FPC when compared with the control group. Future studies will evaluate the value of IDO2 genotyping as a prognostic, early detection marker for pancreatic ductal adenocarcinoma and a predictive marker for novel immune checkpoint therapies.