Next-generation sequencing mutation analysis on biliary brush cytology for differentiation of benign and malignant strictures in primary sclerosing cholangitis.

BACKGROUND AND AIMS: Differentiation of benign and malignant biliary tract strictures on brush material remains highly challenging but is essential for adequate clinical management of patients with primary sclerosing cholangitis (PSC). In this case-control study, biliary brush cytology samples from PSC patients with cholangiocarcinoma (PSC-CCA) were compared with samples from PSC patients without CCA (PSC-control subjects) using next-generation sequencing (NGS). METHODS: Cells on archived slides were dissected for DNA extraction. NGS was performed using a gene panel containing 242 hotspots in 14 genes. Repeated brush samples from the same patient were analyzed to study the consistency of NGS results. In PSC-CCA cases that underwent surgical resection, molecular aberrations in brush samples were compared with NGS data from subsequent resection specimens. RESULTS: Forty patients (20 PSC-CCA and 20 PSC-control subjects) were included. The gene panel detected 22 mutations in 15 of 20 PSC-CCA brush samples, including mutations in TP53 (8 brush samples), K-ras (5), G-nas (3), ERBB2 (1), APC (1), PIK3CA (1), and SMAD4 (1). One G-nas and 3 K-ras mutations were found in 3 of 20 PSC-control brush samples. The sensitivity of the NGS panel was 75% (95% confidence interval, 62%-80%) and specificity 85% (95% confidence interval, 64%-95%). Repeated brush samples showed identical mutations in 6 of 9 cases. Three repeated brush samples demonstrated additional mutations as compared with the first brush sample. In 6 of 7 patients, mutations in brush samples were identical to mutations in subsequent resection specimens. CONCLUSIONS: NGS mutation analysis of PSC brush cytology detects oncogenic mutations with high sensitivity and specificity and seems to constitute a valuable adjunct to cytologic assessment of brush samples.

Cholangiocarcinoma cell proliferation is enhanced in primary sclerosing cholangitis: A role for IL-17A.

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease of the biliary tree and a risk factor for development of cholangiocarcinoma (CCA). The pathogenesis of PSC-related CCA is largely unclear, although it is assumed that chronic inflammatory environment plays a pivotal role. We aimed to investigate the effect of inflammation-related cytokines in PSC on the proliferation rate of cancer cells. For this, the proliferation index in PSC-CCA and sporadic CCA was determined by Ki-67 immunohistochemistry. The percentage of Ki-67 positivity in cancer cells was significantly higher in PSC-CCA than in sporadic CCA (41.3% ± 5.7% vs 25.8% ± 4.1%; P = .038). To assess which cytokines in the inflammatory environment have the potential to stimulate cancer cell proliferation, patient-derived CCA organoids (CCAOs) were exposed to five cytokines related to PSC (Interleukin (IL)-1ß, IL-6, IL-17A, interferon gamma and tumor necrosis factor alpha). Only IL-17A showed a significant stimulatory effect on cell proliferation in CCAOs, increasing organoid size by 45.9% ± 16.4% (P < .01) and proliferation rate by 38% ± 16% (P < .05). IL-17A immunohistochemistry demonstrated that PSC-CCA might express more IL-17A than sporadic CCA. Moreover, correlation analysis in sporadic CCA and PSC-CCA found a significant correlation between IL-17A expression and proliferation. In conclusion, tumor cell proliferation is increased in PSC-CCA cells compared with sporadic CCA cells. IL-17A increases CCA cell proliferation in vitro and may contribute to the high proliferation rate in PSC-CCA in situ. Therefore, IL-17A represents a new potential therapeutic target in (PSC-)CCA, to be tested in future trials.

Primary Sclerosing Cholangitis-Associated Cholangiocarcinoma Demonstrates High Intertumor and Intratumor Heterogeneity.

INTRODUCTION: Intertumor and intratumor heterogeneity may explain the diagnostic challenge and limited efficacy of chemotherapy for primary sclerosing cholangitis-associated cholangiocarcinoma (PSC-CCA). In this study, tumor heterogeneity was assessed through p53 and p16 protein expression analysis and next-generation sequencing (NGS) of TP53 and CDKN2A genetic alterations in PSC-associated CCA. METHODS: Formalin-fixed paraffin-embedded tissue samples from resection material of patients with PSC-CCA or patients with PSC diagnosed with biliary dysplasia were selected. Sections with CCA and foci with dysplastic epithelium were identified by 2 independent gastrointestinal pathologists. Immunohistochemical evaluation of p53 and p16 protein expression and NGS of TP53 and CDKN2A genetic alterations were performed. RESULTS: A total of 49 CCA and 21 dysplasia samples were identified in the resection specimens of 26 patients. P53 protein expression showed loss of expression, wild type, and overexpression in 14%, 63%, and 23% CCA and in 19%, 62%, and 19% dysplasia samples, respectively. P16 protein expression showed negative, heterogeneous, and positive results in 31%, 57%, and 12% CCA and in 33%, 53%, and 14% dysplasia samples, respectively. NGS showed high intertumor and intratumor heterogeneity of TP53 mutations and CDKN2A loss. Nearly 70% of the samples with a TP53 missense mutation demonstrated p53 overexpression, whereas all samples with a TP53 nonsense mutation demonstrated loss of p53 protein expression. DISCUSSION: PSC-associated CCA is characterized by high intertumor and intratumor heterogeneity of both p53/p16 protein expression and genetic alterations in TP53/CDKN2A, indicating that these tumors consist of multiple subclones with substantially different genetic makeup. The high intertumor and intratumor heterogeneity in PSC-CCA should be acknowledged during the development of diagnostic and therapeutic strategies.

Optimal tissue sampling during ERCP and emerging molecular techniques for the differentiation of benign and malignant biliary strictures.

Patients with cholangiocarcinoma have poor survival since the majority of patients are diagnosed at a stage precluding surgical resection, due to locally irresectable tumors and/or metastases. Optimization of diagnostic strategies, with a principal role for tissue diagnosis, is essential to detect cancers at an earlier stage amenable to curative treatment. Current barriers for a tissue diagnosis include both insufficient tissue sampling and a difficult cyto- or histopathological assessment. During endoscopic retrograde cholangiopancreatography, optimal brush sampling includes obtaining more than one brush within an individual patient to increase its diagnostic value. Currently, no significant increase of the diagnostic accuracy for the new cytology brush devices aiming to enhance the cellularity of brushings versus standard biliary brush devices has been demonstrated. Peroral cholangioscopy with bile duct biopsies appears to be a valuable tool in the diagnostic work-up of indeterminate biliary strictures, and may overcome current technical difficulties of fluoroscopic-guided biopsies. Over the past years, molecular techniques to detect chromosomal instability, mutations and methylation profiling of tumors have revolutionized, and implementation of these techniques on biliary tissue during diagnostic work-up of biliary strictures may be awaited in the near future. Fluorescence in situ hybridization has already been implemented in routine diagnostic evaluation of biliary strictures in several centers. Next-generation sequencing is promising for standard diagnostic care in biliary strictures, and recent studies have shown adequate detection of prevalent genomic alterations in KRAS, TP53, CDKN2A, SMAD4, PIK3CA, and GNAS on biliary brush material. Detection of DNA methylation of tumor suppressor genes and microRNAs may evolve over the coming years to a valuable diagnostic tool for cholangiocarcinoma. This review summarizes optimal strategies for biliary tissue sampling during endoscopic retrograde cholangiopancreatography and focuses on the evolving molecular techniques on biliary tissue to improve the differentiation of benign and malignant biliary strictures.

Irritable Bowel Syndrome and Microscopic Colitis: A Systematic Review and Meta-analysis.

BACKGROUND & AIMS: Patients with microscopic colitis and patients with irritable bowel syndrome (IBS) present with similar symptoms. We examined the association between IBS and microscopic colitis in a systematic review and meta-analysis. METHODS: We searched the medical literature to identify cross-sectional surveys or case-control studies reporting the association between microscopic colitis and IBS in 50 or more unselected adult patients. We recorded the prevalence of IBS symptoms in patients with histologically confirmed microscopic colitis, or the prevalence of histologically confirmed microscopic colitis in patients with IBS. Data were pooled using a random-effects model; the association between microscopic colitis and IBS was summarized using an odds ratio (OR) with a 95% confidence interval (CI). RESULTS: The search strategy identified 3926 citations, of which 10 were eligible for our analysis. The pooled prevalence of IBS in patients with microscopic colitis was 33.4% (95% CI, 31.5%-40.6%), but was not significantly higher in patients with microscopic colitis than in patients with diarrhea (OR, 1.39; 95% CI, 0.43-4.47). In 3 cross-sectional surveys, the pooled OR for microscopic colitis in participants with IBS, compared with other patients with diarrhea, was 0.68 (95% CI, 0.44-1.04). In 4 case-control studies the prevalence of IBS in patients with microscopic colitis was significantly higher than in asymptomatic controls (OR, 5.16; 95% CI, 1.32-20.2). CONCLUSIONS: Based on a meta-analysis, one third of patients with microscopic colitis reported symptoms compatible with IBS, but the prevalence of IBS was no higher than in other patients with diarrhea. The odds of microscopic colitis were no higher in patients with IBS compared with other patients with diarrhea. The value of routine colonoscopy and biopsy to exclude microscopic colitis in patients with typical IBS symptoms, unless other risk factors or alarm symptoms are present, remains uncertain.