Prevalence of Germline Sequence Variations Among Patients With Pancreatic Cancer in China

Pancreatic mucinous adenocarcinoma has different clinical characteristics and better prognosis compared to non-specific PDAC: A retrospective observational study

Background

Pancreatic mucinous adenocarcinoma (PMAC) is a rare malignant tumour, and there is limited understanding of its epidemiology and prognosis. Initially, PMAC was considered a metastatic manifestation of other cancers; however, instances of non-metastatic PMAC have been documented through monitoring, epidemiological studies, and data from the Surveillance, Epidemiology, and End Results (SEER) database. Therefore, it is crucial to investigate the epidemiological characteristics of PMAC and discern the prognostic differences between PMAC and the more prevalent pancreatic ductal adenocarcinoma (PDAC).

Methods

The study used data from the SEER database from 2000 to 2018 to identify patients diagnosed with PMAC or PDAC. To ensure comparable demographic characteristics between PDAC and PMAC, propensity score matching was employed. Kaplan-Meier analysis was used to analyse overall survival (OS) and cancer-specific survival (CSS). Univariate and multivariate Cox regression analyses were used to determine independent risk factors influencing OS and CSS. Additionally, the construction and validation of risk-scoring models for OS and CSS were achieved through the least absolute shrinkage and selection operator-Cox regression technique.

Results

The SEER database included 84,857 patients with PDAC and 3345 patients with PMAC. Notably, significant distinctions were observed in the distribution of tumour sites, diagnosis time, use of radiotherapy and chemotherapy, tumour size, grading, and staging between the two groups. The prognosis exhibited notable improvement among married individuals, those receiving acceptable chemotherapy, and those with focal PMAC (p < 0.05). Conversely, patients with elevated log odds of positive lymph node scores or higher pathological grades in the pancreatic tail exhibited a more unfavourable prognosis (p < 0.05). The risk-scoring models for OS or CSS based on prognostic factors indicated a significantly lower prognosis for high-risk patients compared to their low-risk counterparts (area under the curve OS: 0.81-0.82, CSS: 0.80-0.82).

Conclusion

PMAC exhibits distinct clinical characteristics compared to non-specific PDAC. Leveraging these features and pathological classifications allows for accurate prognostication of PMAC or PDAC.

Genetic and other risk factors for pancreatic ductal adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at an advanced stage, resulting in poor prognosis and low 5-year survival rates. While early evidence suggests increased long-term survival in those with screen-detected resectable cancers, surveillance imaging is currently only recommended for individuals with a lifetime risk of PDAC ≥ 5%. Identification of risk factors for PDAC provides opportunities for early detection, risk reducing interventions, and targeted therapies, thus potentially improving patient outcomes. Here, we summarize modifiable and non-modifiable risk factors for PDAC. We review hereditary cancer syndromes associated with risk for PDAC and their implications for patients and their relatives. In addition, other biologically relevant pathways and environmental and lifestyle risk factors are discussed. Future work may focus on elucidating additional genetic, environmental, and lifestyle risk factors that may modify PDAC risk to continue to identify individuals at increased risk for PDAC who may benefit from surveillance and risk reducing interventions.

Population-based BRCA germline mutation screening in the Han Chinese identifies individuals at risk of BRCA mutation-related cancer: experience from a clinical diagnostic center from greater Shanghai area

BACKGROUND

Deleterious BRCA1/2 (BRCA) mutation raises the risk for BRCA mutation-related malignancies, including breast, ovarian, prostate, and pancreatic cancer. Germline variation of BRCA exhibits substantial ethnical diversity. However, there is limited research on the Chinese Han population, constraining the development of strategies for BRCA mutation screening in this large ethnic group.

METHODS

We profile the BRCA mutational spectrum, including single nucleotide variation, insertion/deletion, and large genomic rearrangements in 2,080 apparently healthy Chinese Han individuals and 522 patients with BRCA mutation-related cancer, to determine the BRCA genetic background of the Chinese Han population, especially of the East Han. Incident cancer events were monitored in 1,005 participants from the healthy group, comprising 11 BRCA pathogenic/likely pathogenic (PLP) variant carriers and 994 PLP-free individuals, including 3 LGR carriers.

RESULTS

Healthy Chinese Han individuals demonstrated a distinct BRCA mutational spectrum compared to cancer patients, with a 0.53% (1 in 189) prevalence of pathogenic/likely pathogenic (PLP) variant, alongside a 3 in 2,080 occurrence of LGR. BRCA1 c. 5470_5477del demonstrated high prevalence (0.44%) in the North Han Chinese and penetrance for breast cancer. None of the 3 LGR carriers developed cancer during the follow-up. We calculated a relative risk of 135.55 (95% CI 25.07 to 732.88) for the development of BRCA mutation-related cancers in the BRCA PLP variant carriers (mean age 42.91 years, median follow-up 10 months) compared to PLP-free individuals (mean age 48.47 years, median follow-up 16 months).

CONCLUSION

The unique BRCA mutational profile in the Chinese Han highlights the potential for standardized population-based BRCA variant screening to enhance BRCA mutation-related cancer prevention and treatment.

Use of multi-gene panels in patients at high risk of hereditary digestive cancer: position statement of AEG, SEOM, AEGH and IMPaCT-GENÓMICA consortium

This position statement, sponsored by the Asociación Española de Gastroenterología, the Sociedad Española de Oncología Médica, the Asociación Española de Genética Humana and the IMPaCT-Genómica Consortium aims to establish recommendations for use of multi-gene panel testing in patients at high risk of hereditary gastrointestinal and pancreatic cancer. To rate the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We reached a consensus among experts using a Delphi method. The document includes recommendations on clinical scenarios where multi-gene panel testing is recommended in colorectal cancer, polyposis syndromes, gastric and pancreatic cancer, as well as the genes to be considered in each clinical scenario. Recommendations on the evaluation of mosaicisms, counseling strategies in the absence of an index subject and, finally, constitutional analysis after identification of pathogenic tumor variants are also made.

ITGB6 promotes pancreatic fibrosis and aggravates the malignant process of pancreatic cancer via JAK2/STAT3 signaling pathway

Integrin β6 (ITGB6) is upregulated in multiple tumor types and elevated ITGB6 levels have been detected in patients with chronic pancreatitis. However, the role of ITGB6 in pancreatic fibrosis and cancer remains to be elucidated. In the present study, ITGB6 expression was assessed using western blotting and qRT-PCR. Besides, cell proliferation, cycling, migration, and invasion were evaluated using CCK-8, flow cytometry, wound healing, and transwell assays, respectively. The expression of fibrosis and JAK2/STAT3 signaling markers was detected by western blotting and immunofluorescence analysis. Moreover, nude mice were subcutaneously injected with co-cultured cell suspensions to establish an in vivo model. The results showed that ITGB6 was highly expressed in pancreatic cancer tissues and TGF-β-induced pancreatic stellate cells (PSCs). Inhibition of ITGB6 expression in PSCs resulted in clear inhibition of activated PSC proliferation, migration, and fibrogenesis. Additionally, reduced ITGB6 expression inhibits the JAK2/STAT3 signaling pathway. Interestingly, activators of the JAK2/STAT3 signaling pathway reversed the effects of ITGB6 disruption on PSCs. Activated PSCs notably promoted the proliferation, invasion, and migration of pancreatic cancer cells in a co-culture assay. In contrast, activated PSCs with low ITGB6 expression failed to significantly affect the malignancy of pancreatic cancer cells. Moreover, in vivo results showed that interference with ITGB6 inhibited the activation of PSCs and promoted the development of pancreatic cancer. Silencing ITGB6 inhibited the proliferation, migration, and fibrosis-like effects of activated PSCs and indirectly inhibited the metastasis and malignant process of pancreatic cancer by inhibiting the JAK2/STAT3 signaling pathway. Therefore, ITGB6 is a potential candidate target for pancreatic cancer prevention and treatment.

Case report: Targeted sequencing facilitates the diagnosis and management of rare multifocal pure ground-glass opacities with intrapulmonary metastasis

Introduction

Treatments for multiple ground-glass opacities (GGOs) for which the detection rate is increasing are still controversial. Next-generation sequencing (NGS) may provide additional key evidence for differential diagnosis or optimal therapeutic schedules.

Case presentation

We first reported a rare case in which more than 100 bilateral pulmonary GGOs (91.7% of the GGOs were pure GGOs) were diagnosed as both multiple primary lung cancer and intrapulmonary metastasis. We performed NGS with an 808-gene panel to assess both somatic and germline alterations in tissues and plasma. The patient (male) underwent three successive surgeries and received osimertinib adjuvant therapy due to signs of metastasis and multiple EGFR-mutated tumors. The patient had multiple pure GGOs, and eight tumors of four pathological subtypes were evaluated for the clonal relationship. Metastasis, including pure GGOs and atypical adenomatous hyperplasia, was found between two pairs of tumors. Circulating tumor DNA (ctDNA) monitoring of disease status may impact clinical decision-making.

Conclusions

Surgery combined with targeted therapies remains a reasonable alternative strategy for treating patients with multifocal GGOs, and NGS is valuable for facilitating diagnostic workup and adjuvant therapy with targeted drugs through tissue and disease monitoring via ctDNA.

Detection of G-Quadruplex DNA Structures in Macrophages

In addition to the canonical B-DNA conformation, DNA can fold into different secondary structures. Among them are G-quadruplex structures (G4s). G4 structures are very stable and can fold in specific guanine-rich regions in DNA and RNA. Different in silico, in vitro, and in cellulo experiments have shown that G4 structures form so far in all tested organisms. There are over 700,000 predicted G4s in higher eukaryotes, but it is so far assumed that not all will form at the same time. Their formation is dynamically regulated by proteins and is cell type-specific and even changes during the cell cycle or during different exogenous or endogenous stimuli (e.g., infection or developmental stages) can alter the G4 level. G4s have been shown to accumulate in cancer cells where they contribute to gene expression changes and the mutagenic burden of the tumor. Specific targeting of G4 structures to impact the expression of oncogenes is currently discussed as an anti-cancer treatment. In a tumor microenvironment, not only the tumor cells will be targeted by G4 stabilization but also immune cells such as macrophages. Although G4s were detected in multiple organisms and different cell types, only little is known about their role in immune cells. Here, we provide a detailed protocol to detect G4 formation in the nucleus of macrophages of vertebrates and invertebrates by microscopic imaging.

Understanding the Genetic Landscape of Pancreatic Ductal Adenocarcinoma to Support Personalized Medicine: A Systematic Review

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies worldwide. While population-wide screening recommendations for PDAC in asymptomatic individuals are not achievable due to its relatively low incidence, pancreatic cancer surveillance programs are recommended for patients with germline causative variants in PDAC susceptibility genes or a strong family history. In this study, we sought to determine the prevalence and significance of germline alterations in major genes (ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, TP53) involved in PDAC susceptibility. We performed a systematic review of PubMed publications reporting germline variants identified in these genes in PDAC patients. Overall, the retrieved articles included 1493 PDAC patients. A high proportion of these patients (n = 1225/1493, 82%) were found to harbor alterations in genes (ATM, BRCA1, BRCA2, PALB2) involved in the homologous recombination repair (HRR) pathway. Specifically, the remaining PDAC patients were reported to carry alterations in genes playing a role in other cancer pathways (CDKN2A, STK11, TP53; n = 181/1493, 12.1%) or in the mismatch repair (MMR) pathway (MLH1, MSH2, MSH6, PMS2; n = 87/1493, 5.8%). Our findings highlight the importance of germline genetic characterization in PDAC patients for better personalized targeted therapies, clinical management, and surveillance.

Prevalence of BRCA1 and BRCA2 germline variants in an unselected pancreatic cancer patient cohort in Pakistan

BACKGROUND

BRCA1 and BRCA2 (BRCA1/2) are the most frequently investigated genes among Caucasian pancreatic cancer patients, whereas limited reports are available among Asians. We aimed to investigate the prevalence of BRCA1/2 germline variants in Pakistani pancreatic cancer patients.

METHODS

One hundred and fifty unselected and prospectively enrolled pancreatic cancer patients were comprehensively screened for BRCA1/2 germline variants using denaturing high-performance liquid chromatography and high-resolution melting analyses, followed by DNA sequencing of the variant fragments. The novel variants were analyzed for their pathogenic effect using in-silico tools. Potentially functional variants were further screened in 200 cancer-free controls.

RESULTS

Protein truncating variant was detected in BRCA2 only, with a prevalence of 0.7% (1/150). A frameshift BRCA2 variant (p.Asp946Ilefs*14) was identified in a 71-year-old male patient of Pathan ethnicity, with a family history of abdominal cancer. Additionally, we found a novel variant in BRCA2 (p.Glu2650Gln), two previously reported variants in BRCA1 (p.Thr293Ser) and BRCA2 (p.Ile2296Leu) and a recurrent nonsense variant in BRCA2 (p.Lys3326Ter). These variants were classified as variants of uncertain significance (VUS). It is noteworthy that none of these VUS carriers had a family history of pancreatic or other cancers.

CONCLUSIONS

In this first study, BRCA1/2 pathogenic variant is identified with a low frequency in pancreatic cancer patients from Pakistan. Comprehensive multigene panel testing is recommended in the Pakistani pancreatic cancer patients to enhance genetic understanding in this population.

DNA damage repair mutations in pancreatic cancer- prognostic or predictive?

Objective

The efficacy of platinum-based chemotherapy (PtCh) for pancreatic cancer (PC) patients with DNA damage repair gene mutations (DDRm) compared to those without DDRm remains uncertain.

Methods

After a thorough database searching in PubMed, Embase, and Web of Science, a total of 19 studies that met all the inclusion criteria were identified. The primary outcomes were overall survival (OS) and progression-free survival (PFS) for PC patients with DDRm versus those without DDRm after PtCh.

Results

Patients with advanced-stage PC who have DDRm tend to have longer OS compared to patients without DDRm, regardless of their exposure to PtCh (HR=0.63; I2 = 66%). Further analyses indicated that the effectiveness of PtCh for OS was modified by DDRm (HR=0.48; I2 = 59%). After the first- line PtCh (1L-PtCh), the PFS of advanced-stage PC with DDRm was also significantly improved (HR=0.41; I2 = 0%). For patients with resected PC, regardless of their exposure to PtCh, the OS for patients with DDRm was comparable to those without DDRm (HR=0.82; I2 = 71%). Specifically, for patients with resected PC harboring DDRm who received PtCh (HR=0.85; I2 = 65%) and for those after non-PtCh (HR=0.87; I2 = 0%), the presence of DDRm did not show a significant association with longer OS.

Conclusion

1L-PtCh treatment is correlated with favorable survival for advanced-stage PC patients with DDRm. For resected-stage PC harboring DDRm, adjuvant PtCh had limited effectiveness. The prognostic value of DDRm needs to be further verified by prospective randomized controlled trials.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022302275.

Clinical and genetic characteristics in pancreatic cancer from Chinese patients revealed by whole exome sequencing

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies worldwide, mostly as a result of the absence of early detection and specific treatment solutions. Consequently, identifying mutational profiles and molecular biomarkers is essential for increasing the viability of precision therapy for pancreatic cancer.

Methods

We collected blood and tumor tissue samples from 47 Chinese pancreatic cancer patients and used whole-exome sequencing (WES) to evaluate the genetic landscape.

Results

Our results showed the most frequently somatic alteration genes were KRAS (74.5%), TP53(51.1%), SMAD4 (17%), ARID1A (12.8%), CDKN2A (12.8%), TENM4 (10.6%), TTN (8.5%), RNF43(8.5%), FLG (8.5%) and GAS6 (6.4%) in Chinese PDAC patients. We also found that three deleterious germline mutations (ATM c.4852C>T/p. R1618*, WRN c.1105C>T/p. R369*, PALB2 c.2760dupA/p. Q921Tfs*7) and two novel fusions (BRCA1-RPRML, MIR943 (intergenic)-FGFR3). When compared to the Cancer Genome Atlas (TCGA) database, there is a greater mutation frequency of TENM4 (10.6% vs. 1.6%, p = 0.01), GAS6(6.4% vs. 0.5%, p = 0.035), MMP17(6.4% vs. 0.5%, p = 0.035), ITM2B (6.4% vs. 0.5%, p = 0.035) and USP7 (6.4% vs. 0.5%, p= 0.035) as well as a reduced mutation frequency of SMAD4 (17.0% vs. 31.5%, p = 0.075) and CDKN2A (12.8% vs. 47.3%, p < 0.001) were observed in the Chinese cohort. Among the 41 individuals examined for programmed cell death ligand 1(PD-L1) expression, 15 (36.6%) had positive PD-L1 expression. The median tumor mutational burden (TMB) was found to be 12muts (range, 0124). The TMB index was higher in patients with mutant-type KRAS MUT/TP53 MUT (p < 0.001), CDKN2A (p = 0.547), or SMAD4 (p = 0.064) compared to patients with wild-type KRAS/TP53, CDKN2A, or SMAD4.

Conclusions

We exhibited real-world genetic traits and new alterations in Chinese individuals with cancer of the pancreas, which might have interesting implications for future individualized therapy and medication development.

Diagnostic rate of germline pathogenic variants in pancreatic ductal adenocarcinoma patients using whole genome sequencing

Identification of germline pathogenic variants in cancer patients is critical for treatment planning, genetic counseling, and health policymaking. However, previous estimates of the prevalence of germline etiology of pancreatic ductal adenocarcinoma (PDAC) were biased because they were based only on sequencing data of protein-coding regions of known PDAC candidate genes. To determine the percentage of patients with PDAC carrying germline pathogenic variants, we enrolled the inpatients from the digestive health clinics, hematology and oncology clinics, and surgical clinics of a single tertiary medical center in Taiwan for whole genome sequencing (WGS) analysis of genomic DNA. The virtual gene panel of 750 genes comprised PDAC candidate genes and those listed in the COSMIC Cancer Gene Census. The genetic variant types under investigation included single nucleotide substitutions, small indels, structural variants, and mobile element insertions (MEIs). In 8 of 24 (33.3%) patients with PDAC, we identified pathogenic/likely pathogenic variants, including single nucleotide substitutions and small indels in ATM, BRCA1, BRCA2, POLQ, SPINK1 and CASP8, as well as structural variants in CDC25C and USP44. We identified additional patients carrying variants that could potentially affect splicing. This cohort study demonstrates that an extensive analysis of the abundant information yielded by the WGS approach can uncover many pathogenic variants that could be missed by traditional panel-based or whole exome sequencing-based approaches. The percentage of patients with PDAC carrying germline variants might be much higher than previously expected.

A systematic review and meta-analysis of germline BRCA mutations in pancreatic cancer patients identifies global and racial disparities in access to genetic testing

BACKGROUND

Germline BRCA1 and BRCA2 mutations (gBRCAm) can inform pancreatic cancer (PC) risk and treatment but most of the available information is derived from white patients. The ethnic and geographic variability of gBRCAm prevalence and of germline BRCA (gBRCA) testing uptake in PC globally is largely unknown.

MATERIALS AND METHODS

We carried out a systematic review and prevalence meta-analysis of gBRCA testing and gBRCAm prevalence in PC patients stratified by ethnicity. The main outcome was the distribution of gBRCA testing uptake across diverse populations worldwide. Secondary outcomes included: geographic distribution of gBRCA testing uptake, temporal analysis of gBRCA testing uptake in ethnic groups, and pooled proportion of gBRCAm stratified by ethnicity. The study is listed under PROSPERO registration number #CRD42022311769.

RESULTS

A total of 51 studies with 16 621 patients were included. Twelve of the studies (23.5%) enrolled white patients only, 10 Asians only (19.6%), and 29 (56.9%) included mixed populations. The pooled prevalence of white, Asian, African American, and Hispanic patients tested per study was 88.7%, 34.8%, 3.6%, and 5.2%, respectively. The majority of included studies were from high-income countries (HICs) (64; 91.2%). Temporal analysis showed a significant increase only in white and Asians patients tested from 2000 to present (P < 0.001). The pooled prevalence of gBRCAm was: 3.3% in white, 1.7% in Asian, and negligible (<0.3%) in African American and Hispanic patients.

CONCLUSIONS

Data on gBRCA testing and gBRCAm in PC derive mostly from white patients and from HICs. This limits the interpretation of gBRCAm for treating PC across diverse populations and implies substantial global and racial disparities in access to BRCA testing in PC.

Contribution of germline PALB2 variants to an unselected and prospectively registered pancreatic cancer patient cohort in Pakistan

BACKGROUND

Partner and localizer of BRCA2 (PALB2) is a pancreatic cancer (PC) susceptibility gene reported in Caucasians. However, limited data are available among Asians. We investigated the contribution of PALB2 germline variants to Pakistani PC patients.

METHODS

150 unselected and prospectively enrolled PC patients were comprehensively screened for PALB2 variants, using denaturing high-performance liquid chromatography and DNA sequencing. Novel variants were investigated for their pathogenic effect using in-silico tools. Potentially functional variants were screened in 200 controls.

RESULTS

Twenty-two different PALB2 variants were identified. A missense variant (p.Arg37His) was identified in a 48-years-old male patient with a family history of breast cancer. Another missense variant (p.Trp898Arg) was identified in a 48-years-old male patient with a family history of esophageal cancer. A novel 3' downstream variant (c.∗480A>G) was detected in a 34-years-old female patient with family history of lung cancer. Another novel 3' downstream variant (c.∗417A>C) was identified in a 41-years-old male patient. All these variants were absent in 200 controls. p.Arg37His and p.Trp898Arg were predicted as likely pathogenic. c.∗417A>C and c.∗480A>G were classified as variants of uncertain significance.

CONCLUSION

This is the first study that suggests a minimal contribution of PALB2 variants to PC risk in Pakistani population.

Construction of a Prognostic Model Based on Cuproptosis-Related lncRNA Signatures in Pancreatic Cancer

Aim

The aim of this study is to identify cuproptosis-related lncRNAs and construct a prognostic model for pancreatic cancer patients for clinical use.

Methods

The expression profile of lncRNAs was downloaded from The Cancer Genome Atlas database, and cuproptosis-related lncRNAs were identified. The prognostic cuproptosis-related lncRNAs were obtained and used to establish and validate a prognostic risk score model in pancreatic cancer.

Results

In total, 181 cuproptosis-related lncRNAs were obtained. The prognostic risk score model was constructed based on five lncRNAs (AC025257.1, TRAM2-AS1, AC091057.1, LINC01963, and MALAT1). Patients were assigned to two groups according to the median risk score. Kaplan-Meier survival curves showed that the difference in the prognosis between the high- and low-risk groups was statistically significant. Multivariate Cox analysis showed that our risk score was an independent risk factor for pancreatic cancer patients. Receiver operator characteristic curves revealed that the cuproptosis-related lncRNA model can effectively predict the prognosis of pancreatic cancer. The principal component analysis showed a difference between the high- and low-risk groups intuitively. Functional enrichment analysis showed that different genes were involved in cancer-related pathways in patients in the high- and low-risk groups.

Conclusion

The risk model based on five prognostic cuproptosis-related lncRNAs can well predict the prognosis of pancreatic cancer patients. Cuproptosis-related lncRNAs could be potential biomarkers for pancreatic cancer diagnosis and treatment.