No evidence for germline mutations of the LKB1/STK11 gene in familial pancreatic carcinoma

Identification of high-risk germline variants for the development of pancreatic cancer: Common characteristics and potential guidance to screening guidelines

Pancreatic cancer (PC) is a product of a variety of environmental and genetic factors. Recent work has highlighted the influence of hereditary syndromes on pancreatic cancer incidence. The purpose of this review is to identify the high-risk syndromes, common variants, and risks associated with PC. The study also elucidates common characteristics of patients with these mutations, which is used to recommend potential changes to current screening protocols for greater screening efficacy. We analyzed 8 syndromes and their respective variants: Hereditary Breast and Ovarian Cancer (BRCA1/2), Familial Atypical Multiple Mole Melanoma Syndrome (CDKN2A), Peutz-Jeghers Syndrome (STK11), Lynch Syndrome (PMS2, MLH1, MSH2, MSH6, EPCAM), Ataxia Telangiectasia (ATM), Li-Fraumeni Syndrome (TP53), Fanconi Anemia (PALB2), and Hereditary Pancreatitis (PRSS1, SPINK1, CFTR). Of 587 studies evaluated, 79 studies fit into our inclusion criteria. Information from each study was analyzed to draw conclusions on these variants as well as their association with pancreatic cancer. Information from this review is intended to improve precision medicine and improve criteria for screening.

Current Controversies in Neoadjuvant Therapy for Pancreatic Cancer

Over the last two decades, there have been significant changes in the management of patients with localized pancreatic cancer. The rationale for an evolution toward a neoadjuvant approach and summary of relevant clinical trials is reviewed. Controversies in identifying optimal neoadjuvant therapeutic approaches are discussed.

Early detection of pancreatic cancer

Pancreatic ductal adenocarcinoma is most frequently detected at an advanced stage. Such late detection restricts treatment options and contributes to a dismal 5-year survival rate of 3-15%. Pancreatic ductal adenocarcinoma is relatively uncommon and screening of the asymptomatic adult population is not feasible or recommended with current modalities. However, screening of individuals in high-risk groups is recommended. Here, we review groups at high risk for pancreatic ductal adenocarcinoma, including individuals with inherited predisposition and patients with pancreatic cystic lesions. We discuss studies aimed at finding ways of identifying pancreatic ductal adenocarcinoma in high-risk groups, such as among individuals with new-onset diabetes mellitus and people attending primary and secondary care practices with symptoms that suggest this cancer. We review early detection biomarkers, explore the potential of using social media for detection, appraise prediction models developed using electronic health records and research data, and examine the application of artificial intelligence to medical imaging for the purposes of early detection.

Familial pancreatic cancer: current status

The term 'familial pancreatic cancer (FPC) defines families with at least two first-degree relatives with confirmed pancreatic cancer that do not fulfill the criteria of other inherited cancer syndromes with an increased risk for the development of PC, such as Peutz-Jeghers syndrome, hereditary pancreatitis and hereditary breast and ovarian cancer. FPC is a mostly autosomal dominant inherited tumor syndrome with a heterogeneous phenotype. The major genetic defect has not been identified yet, although mutations, for example in the BRCA2 gene, could be identified in some FPC families. Nevertheless, most experts recommend participation in screening and surveillance programs to high-risk individuals. Most board-approved screening programs are based on endoscopic ultrasound. The first data on the prospective screening of high-risk individuals have demonstrated that precursor lesions of PC can be identified, but false-positive findings do occur.

Genetic testing by cancer site: pancreas

It is estimated that 5% to 10% of pancreatic cancer is familial. Although there is evidence of a major pancreatic cancer susceptibility gene, the majority of families with multiple cases of pancreatic cancer do not have an identifiable causative gene or syndrome. However, a subset of pancreatic cancer is attributable to known inherited cancer predisposition syndromes, including several hereditary breast cancer genes (BRCA1, BRCA2, and PALB2), CDKN2A, hereditary pancreatitis, hereditary nonpolyposis colorectal cancer, and Peutz-Jeghers syndrome. In addition to explaining a proportion of familial pancreatic cancer, individuals with these conditions are at increased risk for pancreatic cancer. Relatives from familial pancreatic cancer kindreds without one of these identifiable syndromes may have as high as a 32-fold risk of pancreatic cancer, depending on the number of affected first-degree relatives. Such high-risk individuals may benefit from increased surveillance, and strategies for early detection of pancreatic cancer are under evaluation.

German national case collection for familial pancreatic cancer (FaPaCa): ten years experience

Familial pancreatic cancer (FPC) is a rare hereditary tumor syndrome. The 10-years experience of the national case collection for familial pancreatic cancer of Germany (FaPaCa) is reported. Since 1999 FaPaCa has collected families with at least two first-degree relatives with confirmed pancreatic cancer (PC), who did not fulfill the criteria of other hereditary tumor syndromes. Histopathological verification of tumor diagnoses, and genetic counseling were prerequisites for enrollment of families in FaPaCa. 94 of 452 evaluated families fulfilled the criteria for partaking in FaPaCa. PC represented the sole tumor entity in 38 (40%) families. In 56 families additional tumor types occurred, including breast cancer (n = 28), colon cancer (n = 20) and lung cancer (n = 11). In 70 (74%) families the pattern of inheritance was consistent with an autosomal dominant trait. Compared to the preceding generation, a younger age of onset was observed in the offspring of PC patients (median: 57 vs. 69 years), indicating anticipation. Mutation analyses of BRCA2, PALB2, CDKN2a, RNASEL, STK11, NOD2, CHEK2 and PALLD, revealed deleterious causative germline mutations of BRCA2 and PALB2 in 2 of 70 (3%) and 2 of 41 (4.9%) German FPC families, respectively. Prospective PC screening with EUS, MRI and MRCP detected precancerous lesions (IPMN, multifocal PanIN2/3) or carcinoma in 5.5% (4 of 72) to 12.5% (9 of 72) of individuals at risk, depending on histological verification. Appropriate inclusion of families at high risk for PC in registries, such as FaPaCa, provides a unique and excellent tool to gain clinical and genetic knowledge of FPC. Focused research projects can be conducted most efficiently, when data of different FPC registries are combined.

German national case collection for familial pancreatic cancer (FaPaCa): ten years experience

Familial pancreatic cancer (FPC) is a rare hereditary tumor syndrome. The 10-years experience of the national case collection for familial pancreatic cancer of Germany (FaPaCa) is reported. Since 1999 FaPaCa has collected families with at least two first-degree relatives with confirmed pancreatic cancer (PC), who did not fulfill the criteria of other hereditary tumor syndromes. Histopathological verification of tumor diagnoses, and genetic counseling were prerequisites for enrollment of families in FaPaCa. 94 of 452 evaluated families fulfilled the criteria for partaking in FaPaCa. PC represented the sole tumor entity in 38 (40%) families. In 56 families additional tumor types occurred, including breast cancer (n = 28), colon cancer (n = 20) and lung cancer (n = 11). In 70 (74%) families the pattern of inheritance was consistent with an autosomal dominant trait. Compared to the preceding generation, a younger age of onset was observed in the offspring of PC patients (median: 57 vs. 69 years), indicating anticipation. Mutation analyses of BRCA2, PALB2, CDKN2a, RNASEL, STK11, NOD2, CHEK2 and PALLD, revealed deleterious causative germline mutations of BRCA2 and PALB2 in 2 of 70 (3%) and 2 of 41 (4.9%) German FPC families, respectively. Prospective PC screening with EUS, MRI and MRCP detected precancerous lesions (IPMN, multifocal PanIN2/3) or carcinoma in 5.5% (4 of 72) to 12.5% (9 of 72) of individuals at risk, depending on histological verification. Appropriate inclusion of families at high risk for PC in registries, such as FaPaCa, provides a unique and excellent tool to gain clinical and genetic knowledge of FPC. Focused research projects can be conducted most efficiently, when data of different FPC registries are combined.

Prevalence of BRCA2 and CDKN2a mutations in German familial pancreatic cancer families

Previous small scale studies reported that deleterious BRCA2 and CDKN2a germline mutations contribute to a subset of families with inherited pancreatic cancer. As the prevalence of those mutations in the setting of familial pancreatic cancer is still not well defined for the German population, we evaluated the presence of BRCA2 and CDKN2a germline mutations in a large cohort of familial pancreatic cancer (FPC) families from the German National Case Collection for Familial Pancreatic Cancer (FaPaCa). Fifty-six FPC families with at least two-first-degree relatives with confirmed pancreatic cancer that did not fulfill the criteria of other tumor predisposition syndromes, were analyzed for BRCA2 and CDKN2a germline mutations by DHPLC and/or direct sequencing. No deleterious CDKN2a mutations were identified in our families suggesting that CDKN2a mutations are unlikely to predispose PC in FPC families without melanoma. No deleterious BRCA2 mutations, but 6 unclassified variants, were detected in our FPC collection. Combining the prevalence of deleterious BRCA2 germline mutations from our previous separate study with the data from this study we were able to much more accurately estimate the BRCA2 carrier frequency for FPC families in the German population. A total of two mutations and 6 unclassified variants (mutation range: 2.8-11.4%) were thus identified in 70 German FPC families, indicating that the prevalence of BRCA2 mutations in the German FPC population is less frequent than previously reported.

Screening of high-risk families for pancreatic cancer

PURPOSE OF REVIEW

To discuss how to recognise and manage high-risk individuals.

RECENT FINDINGS

Publication of initial results of screening for pancreatic cancer from US centres. Several masses and premalignant lesions have been detected, but the detection of the first pancreatic cancer through an organised study of screening has yet to be published. There has been progress in risk stratification; the role of diabetes in predisposing for cancer has been characterised and molecular modalities have been published which could be used in conjunction with imaging in a screening programme. A mutation in the palladin gene was found to segregate with the disease in a family with a clear predisposition for pancreatic cancer, though this has yet to be found in other such kindreds.

SUMMARY

Significant challenges remain to be solved in screening for early pancreatic cancer. Risk stratification needs to be improved and high-risk patients included in research-based screening programmes. It will be impossible to confirm that screening can detect cancers early enough for curative treatment until the results of these prospective studies become available.

The role of mTOR in the management of solid tumors: an overview

Mammalian target of rapamycin (mTOR) is a key protein kinase controlling signal transduction from various growth factors and upstream proteins to the level of mRNA and ribosome with a regulatory effect on cell cycle progression, cellular proliferation and growth. TOR genes were discovered rather serendipitously while investigating the cause of resistance to immunosuppressant rapamycin in yeast. In normal cells, mTOR controls brilliantly the load of signals from its effectors resulting in a normal cell function. On the contrary, in various diseases and mainly in cancer this balance is lost due to mutations or overactivation of upstream pathways leading to a persistent proliferation and tumor growth. What makes mTOR attractive to researchers seems to be its key position which is on the crossroad of various signal pathways (Ras, PI3K/Akt, TSC, NF-kappaB) towards mRNA, ribosome, protein synthesis and translation of significant molecules, the uncontrolled production of which may lead to tumor proliferation and growth. Inhibition of mTOR by rapamycin (a natural product) or its analogs aims to prevent the deleterious effects of the abnormal signaling, regardless at which point of the signal pathway has the abnormality launched. Here, we will review the physiological functions of mTOR, its association to carcinogenesis and the latest evidence regarding the use of mTOR inhibitors in cancer treatment as well as future trends and aims of research.

Caffeic acid phenethyl ester induces apoptosis of human pancreatic cancer cells involving caspase and mitochondrial dysfunction

AIMS

This study aimed to investigate the effect of caffeic acid phenethyl ester (CAPE), an active component isolated from honeybee propolis, in inducing apoptosis in human pancreatic cancer cells.

METHODS

Inhibition of viability of BxPC-3 and PANC-1 cell lines induced by CAPE was estimated by a trypan blue dye exclusion test. The type of cell death in BxPC-3 after CAPE treatment was characterized by observation of morphology, sub-G1 DNA content, annexin-V/PI staining, caspase-3 and caspase-7 assay, and DNA agarose gel electrophoresis.

RESULTS

CAPE (10 microg/ml) resulted in marked inhibition of viability of BxPC-3 (80.4 +/- 4.1%) and PANC-1 (74.3 +/- 2.9%) cells. CAPE induced a time-dependent increase in hypodiploid percentage and a significant decrease in mitochondrial transmembrane potential in BxPC-3 cells. It induced morphological changes of typical apoptosis, but no DNA fragmentation was noted by DNA electrophoresis. The inhibition of growth and increased in the proportion of sub-G(1) cells was partially blocked by pretreatment with the pan-caspase inhibitor Z-VAD-fmk (50 microM) in BxPC-3 cells indicating a caspase-related mechanism in CAPE-induced apoptosis. Caspase-3/caspase-7 activity was approximately 2 times greater in CAPE-treated BxPC-3 cells compared with control cells.

CONCLUSIONS

These results suggest that CAPE is a potent apoptosis-inducing agent. Its action is accompanied by mitochondrial dysfunction and activation of caspase-3/caspase-7.

[Hereditary pancreatic cancer]

An inherited predisposition to pancreatic cancer (PC) is prevalent in about 3% of PC cases and is currently believed to occur in three distinct clinical settings, (1) hereditary tumour predisposition syndromes with an increased risk of PC such as Peutz-Jeghers syndrome and familial atypical multiple mole melanoma, (2) hereditary pancreatitis and cystic fibrosis, in which genetically determined early-age changes of the pancreas can predispose to the development of PC, and (3) familial pancreatic cancer syndrome (FPC). According to a recent consensus conference, high-risk individuals from PC-prone families should be enrolled in board-approved, prospective, controlled screening programs at expert centres. Based on the available data, prophylactic pancreatectomy is not indicated, since the underlying causative gene defect of the FPC syndrome is still unknown and the penetrance of PC in other tumour predisposition syndromes is either low or yet undetermined. In case of the diagnosis of a PC or high-grade precursor lesions, a prophylactic extension of the resection can be considered, since patients with hereditary PC often develop multifocal pancreatic lesions.

Evaluation of the 4q32-34 locus in European familial pancreatic cancer

BACKGROUND

Familial pancreatic cancer (FPC) describes a group of families where the inheritance of pancreatic cancer is consistent with an autosomal-dominant mode of inheritance. The 4q32-34 region has been previously identified as a potential locus for FPC in a large American family.

METHODS

The region was allelotyped in 231 individuals from 77 European families using nine microsatellite markers, and haplotyping was possible in 191 individuals from 41 families. Families were selected based on at least two affected first-degree relatives with no other cancer syndromes.

RESULTS

Linkage to most of the locus was excluded based on LOD scores less than -2.0. Eight families were excluded from linkage to 4q32-34 based on haplotypes not segregating with the disease compared with a predicted six to seven families. Two groups of families were identified, which seem to share common alleles within the minimal disease-associated region of 4q32-34, one group with an apparently earlier age of cancer death than the other pancreatic cancer families. Four genes were identified with potential tumor suppressor roles within the locus in regions that could not be excluded based on the LOD score. These were HMGB2, PPID, MORF4, and SPOCK3. DNA sequence analysis of exons of these genes in affected individuals and in pancreatic cancer cell lines did not reveal any mutations.

CONCLUSION

This locus is unlikely to harbor a FPC gene in the majority of our European families.

Familial pancreatic cancer syndromes

Hereditary pancreatic cancer (PC) is rare and extremely heterogeneous, and it accounts for approximately 2% of all PC cases. The major component of hereditary PC is the familial pancreatic cancer syndrome. Although up to 20% of hereditary PC cases are associated with germline mutations in the BRCA2, CDKN2A, PRSS1,STKI1, or MMR genes, the major underlying gene defect(s) is still unknown. Although hereditary PC is rare, the data on PC families that have been collected by various study groups worldwide provide a unique opportunity to evaluate the natural history, causative gene alterations, new diagnosis and chemoprevention strategies as well as treatment modalities.

Prophylaktische Chirurgie des Pankreas

The goal of prophylactic surgery is to prevent malignant growth in patients with hereditary tumor predisposition. The pancreas presents as particularly challenging, due to the difficulty of operation and comparatively high risk of morbidity and even mortality. In addition, partial operative procedures and, more significantly, total resection lead to exocrine pancreas insufficiency and secondary diabetes, with grave consequences for the patient. Hereditary tumor predisposition syndromes that can result in pancreaticoduodenal endocrine tumors (PET) include multiple endocrine neoplasia type 1 syndrome and von Hippel-Lindau syndrome. As penetrance is maximally 70-80% and the 10-year survival rate over 80%, prophylactic pancreatic resection without evidence of a tumor is not indicated. However, prophylactic extension of a resection would be advised, should a PET be diagnosed. Patients predisposed to developing ductal pancreatic carcinoma (PC) are at risk of familial pancreatic cancer syndrome (FPC), hereditary pancreatitis, and other hereditary tumor predisposition syndromes such as Peutz-Jeghers syndrome and familial atypical multiple mole-melanoma syndrome. As the gene defect responsible for FPC has yet to be identified and the penetrance of PC in the other tumor predisposition syndromes is low or unknown, a prophylactic pancreatectomy based on today's knowledge is not indicated. Prophylactic extension of the resection is advisable should PC or high-grade PanIN lesions be diagnosed, as these patients often present with multifocal dysplasia and even carcinoma.