KRAS mutations in cell-free DNA from preoperative and postoperative sera as a pancreatic cancer marker: a retrospective study

Comprehensive genomic profile of cholangiocarcinomas in China

Cholangiocarcinoma (CCA) is a primary malignancy, which is often diagnosed as locally advanced or metastatic. Previous studies have revealed genomic characteristics of CCA in Western patients, however comprehensive genomic features of CCA in Chinese patients have not been well understood. To explore the specific genomic characteristics of Chinese patients with CCA, a total of 66 patients with CCA, including 44 intrahepatic CCA (iCCA) and 22 extrahepatic CCA (exCCA) cases, were studied. The most commonly altered genes in CCAs were TP53 (62.12%, 41/66), KRAS (36.36%, 24/66), SMAD4 (24.24%, 16/66), TERT (21.21%, 14/66), ARID1A (19.70%, 13/66), CDKN2A (19.70%, 13/66), KMT2C (9.09%, 6/66) and RBM10 (9.09%, 6/66), ERBB2 (7.58%, 5/66) and BRAF (7.58%, 5/66). Many gene mutations, including STK11, CCND1 and FGF19, were only found in iCCA. RBM10 mutations were found to be significantly higher in exCCA. The gene mutations of neurofibromin 1, STK11, CCND1 and FBXW7 specifically occurred in males, whereas gene mutations of ERBB2, AXIN2 and CREBBP specifically occurred in females. ERBB2 mutations were significantly associated with the sex of patients with CCA. Mutations in PIK3CA, FGFR2 and ZNF750 were significantly associated with the age of patients with CCA and TERT mutations were significantly associated with tumor differentiation. Alterations in KMT2C, PBRM1, AXIN2, MAGI2, BRCA2 and SPTA1 were associated with tumor mutational burden. The findings of the present study suggest that targeted sequencing, using next-generation sequencing technology, provides comprehensive and accurate information on genomic alterations, which will provide novel potential biomarkers for the diagnosis of CCA and may guide precise therapeutic strategies for Chinese patients with CCA.

Moving the Target on the Optimal Adjuvant Strategy for Resected Pancreatic Cancers: A Systematic Review with Meta-Analysis

Combination regimens have shown superiority over single agents in the adjuvant treatment of resected pancreatic cancer (PC), but there are no data supporting definition of the best regimen. This work aimed to compare the efficacy and safety of mFOLFIRINOX, gemcitabine+capecitabine, and gemcitabine+nab/paclitaxel in PC patients. A meta-analysis was performed for direct comparison between trials comparing combination regimens and gemcitabine monotherapy. Subsequently, an indirect comparison was made between trials investigating the efficacy and safety of mFOLFIRINOX, gemcitabine+capecitabine, and gemcitabine+nab/paclitaxel because of the same control arm (gemcitabine). A total of three studies met the selection criteria and were included in our indirect comparison. Indirect comparisons for efficacy outcomes showed a benefit in terms of DFS (disease-free survival)/EFS (event-free survival)/RFS (relapse-free survival) for both mFOLFIRINOX versus gemcitabine+capecitabine (HR 0.69, 95% CI 0.52–0.91) and versus gemcitabine+nab/paclitaxel (HR 0.67, 95% CI 0.50–0.90). No significant advantage was registered for OS (overall survival). Indirect comparisons for safety showed an increase in terms of G3-5 AEs (with the exception of neutropenia) for mFOLFIRINOX versus gemcitabine+capecitabine (RR 1.24, 95% CI 1.03–1.50), while no significant differences were observed versus gemcitabine+nab/paclitaxel. According to our results, mFOLFIRINOX is feasible and manageable and could represent a first option for fit PC resected patients.

Kras mutation correlating with circulating regulatory T cells predicts the prognosis of advanced pancreatic cancer patients

Purpose

Kras mutation and abnormal immune status are associated with pancreatic cancer development and progression. In this study, we evaluated the Kras mutation status in circulating tumor DNA and circulating T cell subsets in a cohort of advanced pancreatic cancer patients.

Methods

Samples were retrospectively obtained from a series of 210 pathological advanced pancreatic cancer patients between 2012 and 2014. The Kras mutation status was detected in cell‐free circulating tumor DNA (ctDNA) by ddPCR and circulating T cell subsets were analyzed by flow cytometry.

Results

Univariate analysis found that tumor node metastasis (TNM) stage, chemotherapy, circulating regulatory T cells, CA19‐9 levels, CA125 levels, and Kras^G12D and Kras^G12V mutations were significantly related to overall survival in advanced pancreatic cancer patients. Multivariate analysis identified that TNM stage (P = .03, HR:1.422), Tregs (P = .004, HR:1.522), CA19‐9 levels (P = .009, HR:1.488), Kras^G12D mutation (P = .044, HR:1.353), and Kras^G12V mutation (P = .001, HR:1.667) were independent prognostic markers. Furthermore, we found that Kras^G12V mutation in ctDNA was correlated with high circulating proportion of Tregs, and patients with both Kras^G12V mutation and high levels of Tregs were associated with extremely poor survival in advanced pancreatic cancer.

Conclusion

Kras^G12V mutation was associated with high circulating regulatory T cell levels, and both of them predicted worse prognosis in advanced pancreatic cancer patients.

Pathogenesis of multiple pancreatic cancers involves multicentric carcinogenesis and intrapancreatic metastasis

There are increased opportunities in oncology clinics to identify multiple pancreatic ductal adenocarcinomas (PDAC) that co-occur simultaneously or arise metachronously in the pancreatic parenchyma, yet their pathogenesis remains elusive. We hypothesized that two potential pathways, multicentric carcinogenesis and intrapancreatic metastasis, might contribute to forming multiple PDAC. Among 241 resected cases, we identified 20 cancer nodules from nine patients with multiple PDAC (six with synchronous PDAC, one with metachronous PDAC, and two with both synchronous and metachronous PDAC). Integrated clinical, pathological, and mutational analyses, using TP53 and SMAD4 immunostaining and targeted next-generation sequencing of 50 cancer-related genes, were conducted to examine the intertumor relationships. Four of the nine patients were assessed as having undergone multicentric carcinogenesis because of heterogeneity of immunohistochemical and/or mutation characteristics. In contrast, tumors in the other five patients showed intertumor molecular relatedness. Two of these five patients, available for matched sequencing data, showed two or more shared mutations. Moreover, all the smaller nodules in these five patients showed identical TP53 and SMAD4 expression patterns to the corresponding main tumors. Consequently, these five patients were considered to have undergone intrapancreatic metastasis. None of the five smaller nodules arising from intrapancreatic metastasis was accompanied by pancreatic intraepithelial neoplasia, and three of them were tiny (≤1mm). Patients whose tumors resulted from intrapancreatic metastasis appeared to have higher disease stages and worse outcome than those with tumors from multicentric carcinogenesis. Our results provide insight into pancreatic carcinogenesis, showing that the development of multiple PDAC involves distinct evolutionary paths that potentially affect patient prognosis.

Sequential molecular and cytologic analyses provides a complementary approach to the diagnosis of pancreatic cystic lesions: a decade of clinical practice

INTRODUCTION

Many pancreatic cystic lesions (PCL) are of neoplastic nature with potential to progress to pancreatic adenocarcinoma. Early stratification of patients to either clinical observation or surgical intervention can considerably increase the survival rate. Recent studies have shown the value of molecular analysis to current diagnostic modalities.The aim of this study is to evaluate the diagnostic improvement by utilizing multiple sequential cytologic and molecular cyst fluid analyses.

MATERIALS AND METHODS

We prospectively evaluated 58 patients for whom multiple endoscopic ultrasound-guided fine-needle aspiration of cyst fluid specimens were available. Specimens were subjected to next generation sequencing to identify any recurrent gene mutations commonly found in PCL. The molecular findings were compared with cytologic and final diagnoses.

RESULTS

Cytologic diagnoses were classified into 3 groups: non-diagnostic (first visit: 33.9%, cumulative: 15.8%, P = 0.03), negative (1st visit: 53.6%, cumulative: 56.1%, P = 0.85) and atypical/suspicious/positive (first visit: 12.5%, cumulative: 28.1%, P = 0.06). The mutational analyses were clustered into indeterminate/failure (first visit: 1.7%, cumulative: 0%), KRAS/GNAS/VHL group (first visit: 50.0%, cumulative: 53.4%) and any mutation (first visit: 50.0%, cumulative: 53.4%). Mutational analysis identifies up to 72% and 71% whereas cytologic analysis classified up to 46% and 63% of lesions correctly in first and multiple visits, respectively.

CONCLUSIONS

The cytology and molecular analyses provide a complementary approach to patients with PCL. Power of molecular analysis in detection of a neoplastic lesion is significantly higher in one visit (P = 0.01) with comparable detection rates (P = 0.43) for both cytologic and molecular analyses after multiple visits.

KRAS Mutant Allele Fraction in Circulating Cell-Free DNA Correlates With Clinical Stage in Pancreatic Cancer Patients

Background: The research on circulating tumor DNA (ctDNA) in pancreatic cancer (PC) has emerged recently. Although the detection rate of the KRAS mutation in ctDNA was relatively consistent with that in tumor tissue, whether the KRAS mutant allele fraction (MAF) differed was still not reported. So far, the clinical application of ctDNA detection in PC remains inconclusive. Methods: Plasma samples were collected from 110 PC and 52 pancreatic benign (PB) disease patients. The detection of KRAS mutation in ctDNA was performed using droplet digital PCR and compared with that in matched tumor tissue. We assessed the utility of KRAS MAFs in ctDNA and tissue for pancreatic malignancy assessment. Results: We found that KRAS MAF in ctDNA of PC patients was higher than that of PB patients, and was obviously associated with tumor staging and distant metastasis. However, KRAS MAF in ctDNA was significantly different from that in matched tissue. KRAS MAF in tumor tissue had no significant correlation with the clinical status. In addition, a ROC curve analysis revealed that mutant KRAS ctDNA combined with CA19-9 could increase the sensitivity rate of early-stage PC prediction, compared with CA19-9 test alone. Conclusion: The MAF of KRAS in ctDNA was related to the clinical stage of PC (p = 0.001). Mutant KRAS ctDNA could improve the sensitivity in early diagnosis of PC as a complement to CA19-9. Our study suggested that KRAS mutation in ctDNA could be a valuable circulating biomarker for the malignancy assessment in PC.

Circulating tumor DNA as a prognostic indicator in resectable pancreatic ductal adenocarcinoma: A systematic review and meta-analysis

Circulating tumor DNA (ctDNA) is a promising prognostic biomarker in various cancers. Due to the high recurrence rate of resectable pancreatic ductal adenocarcinoma (PDAC), effective strategies for prognostic stratification are necessary. Yet, for resectable PDAC, prognostic impact of ctDNA lacks systemic evidence. We sought to investigate the prognostic significance of baseline ctDNA and postoperative ctDNA in patients with resectable PDAC. PubMed, EMBASE, and the Cochrane library were searched up to March 2019. Five studies met the inclusion criteria, and 375 patients were pooled for the meta-analysis. Positive ctDNA significantly indicated poor overall survival (at baseline, hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.13-4.56; postoperative, HR 3.66, 95% CI 1.45-9.28). Patients with detectable ctDNA showed the trend to have higher risk for disease recurrence than those without detectable ctDNA (at baseline, HR 1.96, 95% CI 0.65-5.87; postoperative, HR 2.20, 95% CI 0.99-4.87). The results were consistent regardless of pre- or post-operative ctDNA. There was no significant heterogeneity among the included studies. In conclusion, our meta-analysis revealed that ctDNA, either at baseline or postoperative, might be a useful prognostic biomarker for stratifying risk of death and recurrence in resectable PDAC.

Prognostic significance of the postoperative level and recovery rate of serum albumin in patients with curatively resected pancreatic ductal adenocarcinoma

The aim of the present study was to investigate the clinicopathological features and prognostic factors associated with pre- and postoperative serum albumin levels in patients with curatively resected pancreatic ductal adenocarcinoma (PDAC). To achieve this, the data of patients who underwent pancreatectomy for PDAC between January 1995 and March 2016 were retrospectively reviewed, and the pre- and postoperative serum albumin levels at postoperative months (POMs) 3, 6, and 12 were evaluated. The serum albumin recovery rate was also investigated. A total of 196 patients were enrolled in the present study. In the multivariate Cox regression analysis, lymph node metastasis [hazard ratio (HR): 1.65; P=0.022], serum albumin level at POM 12 (≥3.9 g/dl; HR: 0.60; P=0.017), and serum albumin recovery rate at POM 12 (≥1.00; HR: 0.60; P=0.017) were independent prognostic factors for disease-free survival. Lymph node metastasis (HR: 1.79; P=0.013) and serum albumin level at POM 12 (≥3.9 g/dl) (HR: 0.60; P=0.033) were independent prognostic factors for overall survival. These results indicated that the postoperative level and recovery rate of serum albumin are potential biomarkers for predicting the prognosis of patients with curatively resected PDAC. However, further studies are required in order to investigate the survival benefit of increasing postoperative serum albumin levels in these patients.

Liquid Biopsy Approach for Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is a public health problem because of its increasing incidence, the absence of early diagnostic tools, and its aggressiveness. Despite recent progress in chemotherapy, the 5-year survival rate remains below 5%. Liquid biopsies are of particular interest from a clinical point of view because they are non-invasive biomarkers released by primary tumours and metastases, remotely reflecting disease burden. Pilot studies have been conducted in pancreatic cancer patients evaluating the detection of circulating tumour cells, cell-free circulating tumour DNA, exosomes, and tumour-educated platelets. There is heterogeneity between the methods used to isolate circulating tumour elements as well as the targets used for their identification. Performances for the diagnosis of pancreatic cancer vary depending of the technique but also the stage of the disease: 30–50% of resectable tumours are positive and 50–100% are positive in locally advanced and/or metastatic cases. A significant prognostic value is demonstrated in 50–70% of clinical studies, irrespective of the type of liquid biopsy. Large prospective studies of homogeneous cohorts of patients are lacking. One way to improve diagnostic and prognostic performances would be to use a combined technological approach for the detection of circulating tumour cells, exosomes, and DNA.

The diagnostic accuracy of circulating free DNA for the detection of KRAS mutation status in colorectal cancer: A meta-analysis

KRAS mutations have been reported as a reliable biomarker for epidermal growth factor receptor (EGFR) targeted therapy and are also associated with poor prognosis in colorectal cancer (CRC) patients. However, limitations of detecting KRAS mutations in tissues are obvious. KRAS mutations in the peripheral blood can be detected as an alternative to tissue analysis. The objective of this meta‐analysis was to evaluate the diagnostic value of cfDNA (circulating free DNA) compared with tissues and to investigate the prognostic potential of cfDNA KRAS mutations in CRC patients. Searches were performed in PubMed, Embase, and Cochrane Library for published studies. We extracted true‐positive (TP), false‐positive (FP), false‐negative (FN), true‐negative (TN) values, survival rate of CRC patients with mutant and wild‐type KRAS and calculated pooled sensitivity and specificity, positive/negative likelihood ratios [PLRs/NLRs], diagnostic odds ratios [DORs], and corresponding 95% confidence intervals [95% CIs]. We also generated a summary receiver operating characteristic (SROC) curve to evaluate the overall diagnostic potential. Totally, 31 relevant studies were recruited and used for the meta‐analysis on the efficacy of cfDNA testing in detecting KRAS mutations. The pooled sensitivity, specificity, PLR, NLR, and DOR were 0.637 (95% CI: 0.607‐0.666), 0.943 (95% CI: 0.930‐0.954), 10.024 (95% CI: 6.912‐14.535), 0.347 (95% CI: 0.269‐0.447), and 37.882 (95% CI: 22.473‐63.857), respectively. The area under the SROC curve was 0.9392. Together, the results suggest that detecting KRAS mutations in cfDNA has adequate diagnostic efficacy in terms of specificity. There is a promising role for cfDNA in the detection of KRAS mutations in CRC patients. However, prospective studies with larger patient cohorts are still required before definitive conclusions of the prognostic potential of cfDNA KRAS mutations in CRC patients were drawn.

Clinical significance of the mutational landscape and fragmentation of circulating tumor DNA in renal cell carcinoma

Reliable biomarkers for renal cell carcinoma (RCC) have yet to be determined. Circulating tumor DNA (ctDNA) is an emerging resource to detect and monitor molecular characteristics of various tumors. The present study aims to clarify the clinical utility of ctDNA for RCC. Fifty-three patients histologically diagnosed with clear cell RCC were enrolled. Targeted sequencing was carried out using plasma cell-free DNA (cfDNA) and tumor DNA. We applied droplet digital PCR (ddPCR) to validate detected mutations. cfDNA fragment size was also evaluated using a microfluidics-based platform and sequencing. Proportion of cfDNA fragments was defined as the ratio of small (50-166 bp) to large (167-250 bp) cfDNA fragments. Association of mutant allele frequency of ctDNA with clinical course was analyzed. Prognostic potential was evaluated using log-rank test. A total of 38 mutations across 16 (30%) patients were identified from cfDNA, including mutations in TP53 (n = 6) and VHL (n = 5), and median mutant allele frequency of ctDNA was 10%. We designed specific ddPCR probes for 11 mutations and detected the same mutations in both cfDNA and tumor DNA. Positive ctDNA was significantly associated with a higher proportion of cfDNA fragments (P = .033), indicating RCC patients with ctDNA had shorter fragment sizes of cfDNA. Interestingly, the changes of mutant allele frequency in ctDNA concurrently correlated with clinical course. Positive ctDNA and fragmentation of cfDNA were significantly associated with poor cancer-specific survival (P < .001, P = .011). In conclusion, our study shows the clinical utility of ctDNA status and cfDNA fragment size as biomarkers for prognosis and disease monitoring in RCC.

Prognostic value of circulating cell-free DNA in patients with pancreatic cancer: A systemic review and meta-analysis

Because of the deep research about tumorigenesis mechanism, the cognition of cancer has been transferred to molecular level from morphology. Previous articles reported a potential connection between circulating cell-free DNA (cfDNA) and prognosis of pancreatic cancer. A total of 18 related articles including 1243 patients were enrolled to access the relationship between cfDNA and prognosis of pancreatic cancer. The hazard ratio (HR) was used to combine the univariate and multivariate results of included studies. Our result performed that the cfDNA had significant prognostic value in predicting OS (HR = 2.41, 95%CI: 1.93-3.02, I2 = 60%) and PFS (HR = 2.47, 95%CI: 1.80-3.40, I2 = 0%) in univariate analysis. The multivariate analyses about OS (HR = 2.57, 95%CI: 1.95-3.38, I2 = 66%) and PFS (HR = 2.31, 95%CI: 1.47-3.64, I2 = 0%) also showed significance. In conclusion, the cfDNA was a significant prognostic factor for OS and PFS in patients with pancreatic cancer. The mutation (Kras, ERBB2-exon17 and KrasG12V), circulating tumor DNA (ctDNA) presence, hypermethylation and higher concentration of cfDNA were both associated with worse survival results in pancreatic cancer.

The emerging role of liquid biopsy in diagnosis, prognosis and treatment monitoring of pancreatic cancer

Circulating tumor DNA, circulating tumor cells and tumor-related exosomes may offer new opportunities to provide insights into the biological and clinical characteristics of a neoplastic disease. They represent alternative routes for diagnostic and prognostic purposes, and for predicting and longitudinally monitoring response to treatment and disease progression. Hence, circulating biomarkers represent promising noninvasive tools in the scenario of pancreatic cancer, where neither molecular nor clinical predictors of treatment benefit have been identified yet. This review aims to provide an overview of the current status of circulating biomarker research in pancreatic cancer, and discusses their potential clinical utility to facilitate clinical decision-making.

Liquid biopsies for management of pancreatic cancer

Pancreatic cancer is one of the main causes of cancer-related deaths worldwide. It is asymptomatic at an early stage, and most diagnosis occurs when the disease is already at a late stage, by which time the tumor is nonresectable. In order to increase the overall survival of patients with pancreatic cancer, as well as to decrease the cancer burden, it is necessary to perform early diagnosis, prognosis stratifications and cancer monitoring using accurate, minimally invasive, and cost-effective methods. Liquid biopsies seek to detect tumor-associated biomarkers in a variety of extractable body fluids and can help to monitor treatment response and disease progression, and even predict patient outcome. In patients with pancreatic cancer, tumor-derived materials, primarily circulating tumor DNA, circulating tumor cells and exosomes, are being studied for inclusion in the management of the disease. This review focuses on describing the biology of these biomarkers, methods for their enrichment and detection, as well as their potential for clinical application. Moreover, we discuss the future direction of liquid biopsies and introduce how they can be exploited toward point of care personalized medicine for the management of pancreatic cancer.