Abstract Background Microsatellite instability (MSI) occurs in several cancer types and is commonly used for prognosis and as a predictive biomarker for immune checkpoint therapy. Methods We analyzed n = 263 formalin‐fixed paraffin‐embedded (FFPE) tumor specimens (127 colorectal cancer (CRC), 55 endometrial cancer (EC), 33 stomach adenocarcinoma (STAD), and 48 solid tumor specimens of other tumor types) with a capillary electrophoresis based multiplex monomorphic marker MSI‐PCR panel and an amplicon‐based NGS assay for microsatellite instability (MSI+). In total, n = 103 (39.2%) cases with a known defect of the DNA mismatch repair system (dMMR), determined by a loss in protein expression of MSH2/MSH6 ( n = 48, 46.6%) or MLH1/PMS2 ( n = 55, 53.4%), were selected. Cases with an isolated loss of MSH6 or PMS2 were excluded. Results The overall sensitivity and specificity of the NGS assay in comparison with the MSI‐PCR were 92.2% and 98.8%. With CRC cases a nearly optimal concordance was reached (sensitivity 98.1% and specificity 100.0%). Whereas EC cases only show a sensitivity of 88.6% and a specificity of 95.2%, caused by several cases with instability in less than five monomorphic markers, which could be difficult to analyze by NGS (subtle MSI+ phenotype). Conclusions MSI analysis of FFPE DNA by NGS is feasible and the results show a high concordance in comparison with the monomorphic marker MSI‐PCR. However, cases with a subtle MSI+ phenotype, most frequently manifest in EC, have a risk of a false‐negative result by NGS and should be preferentially analyzed by capillary electrophoresis.
Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers. Several local and systemic therapies are available for patients with HCC depending on the stage of the disease. In clinical practice, treatment decision-making, and sequencing may be very heterogeneous.In this study, we retrospectively analyzed treatment algorithms in 2101 patients with HCC treated from 2000 to 2015 at Hannover Medical School, Germany.Transarterial chemoembolization was the most common initial treatment (n = 545; 25.9%), followed by resection (n = 435, 20.7%), local-ablative procedures (n = 283, 13.5%), systemic therapies (n = 275, 13.1%), and liver transplantation (n = 52; 2.5%). Most patients were treated only once (n = 960; 59.6%). A total of 433 (26.9%) and 160 (9.9%) patients received a second line and third line treatment after recurrent or progressive disease. Patients with more than one treatment line were diagnosed at significantly earlier disease stages (P < 0.001). Using binary logistic regression, AFP ≤ 200 μg/L, albumin > 36 g/L, and small tumor size (≤50 mm) were identified as predictors of achieving more than one treatment line. Subsequent treatment stage migration to a therapy suggested for the next advanced stage occurred only in 56.9%, whereas 43.1% received treatments suggested for earlier disease stages. Only 16% of all treated patients received systemic therapy in the salvage setting.Most patients were treated only once, and only a minority of patients received systemic treatment. The high dropout rate for subsequent therapies needs to be considered within therapy decision-making. There is an urgent need for prospective studies to define the best time point when to switch patients from local to systemic therapies.
Abstract Invasive lobular carcinoma (ILC) is a special breast cancer type characterized by noncohesive growth and E‐cadherin loss. Focal activation of P‐cadherin expression in tumor cells that are deficient for E‐cadherin occurs in a subset of ILCs. Switching from an E‐cadherin deficient to P‐cadherin proficient status (EPS) partially restores cell–cell adhesion leading to the formation of cohesive tubular elements. It is unknown what conditions control EPS. Here, we report on EPS in ILC metastases in the large bowel. We reviewed endoscopic colon biopsies and colectomy specimens from a 52‐year‐old female (index patient) and of 18 additional patients (reference series) diagnosed with metastatic ILC in the colon. EPS was assessed by immunohistochemistry for E‐cadherin and P‐cadherin. CDH1 /E‐cadherin mutations were determined by next‐generation sequencing. The index patient's colectomy showed transmural metastatic ILC harboring a CDH1 /E‐cadherin p.Q610* mutation. ILC cells displayed different growth patterns in different anatomic layers of the colon wall. In the tunica muscularis propria and the tela submucosa, ILC cells featured noncohesive growth and were E‐cadherin‐negative and P‐cadherin‐negative. However, ILC cells invading the mucosa formed cohesive tubular elements in the intercryptal stroma of the lamina propria mucosae. Inter‐cryptal ILC cells switched to a P‐cadherin‐positive phenotype in this microenvironmental niche. In the reference series, colon mucosa infiltration was evident in 13 of 18 patients, one of which showed intercryptal EPS and conversion to cohesive growth as described in the index patient. The large bowel is a common metastatic site in ILC. In endoscopic colon biopsies, the typical noncohesive growth of ILC may be concealed by microenvironment‐induced EPS and conversion to cohesive growth.
Abstract Background & Aims Biliary tract cancer is a rare tumour entity characterized by a poor prognosis. We aimed to identify prognostic factors and create a prognostic score to estimate survival. Methods Clinical data of the training set, consisting of 569 patients treated from 2000 to 2010 at Hannover Medical School, were analysed. A prognostic model defining three prognostic risk groups was derived from Cox regression analyses. The score was applied and validated in an independent cohort of 557 patients from four different German centres. Results Median overall survival ( OS ) was 14.5 months. If complete resection was performed, the patients had a significantly improved OS (23.9 months; n=242) as compared to patients with non‐resectable tumours (9.1 months; n=329, P <.0001). Based on univariable and multivariable analyses of clinical data, a prognostic model was created using variables available before treatment. Those were age, metastasis, C‐reactive protein ( CRP ), international normalized ratio ( INR ) and bilirubin. The prognostic score distinguished three groups with a median OS of 21.8, 8.6 and 2.6 months respectively. The validation cohort had a median OS of 20.2, 14.0 and 6.5 months respectively. The prognostic impact of the score was independent of the tumour site and of treatment procedures. Conclusions Here, we identified prognostic factors and propose a prognostic score to estimate survival, which can be applied to all patients independent of tumour site and before initial treatment. Further validation in prospective trials is required.
Background and Aims Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer and a highly lethal malignancy. Chemotherapeutic options are limited, but a considerable subset of patients harbors genetic lesions for which targeted agents exist. Fibroblast growth factor receptor 2 (FGFR2) fusions belong to the most frequent and therapeutically relevant alterations in ICC, and the first FGFR inhibitor was recently approved for the treatment of patients with progressed, fusion‐positive ICC. Response rates of up to 35% indicate that FGFR‐targeted therapies are beneficial in many but not all patients. Thus far, no established biomarkers exist that predict resistance or response to FGFR‐targeted therapies in patients with ICC. Approach and Results In this study, we use an autochthonous murine model of ICC to demonstrate that FGFR2 fusions are potent drivers of malignant transformation. Furthermore, we provide preclinical evidence that the co‐mutational spectrum acts not only as an accelerator of tumor development, but also modifies the response to targeted FGFR inhibitors. Using pharmacologic approaches and RNA‐interference technology, we delineate that Kirsten rat sarcoma oncogene (KRAS)–activated mitogen‐activated protein kinase signaling causes primary resistance to FGFR inhibitors in FGFR2 fusion–positive ICC. The translational relevance is supported by the observation that a subset of human FGFR2 fusion patients exhibits transcriptome profiles reminiscent of KRAS mutant ICC. Moreover, we demonstrate that combination therapy has the potential to overcome primary resistance and to sensitize tumors to FGFR inhibition. Conclusions Our work highlights the importance of the co‐mutational spectrum as a significant modifier of response in tumors that harbor potent oncogenic drivers. A better understanding of the genetic underpinnings of resistance will be pivotal to improve biomarker‐guided patient selection and to design clinically relevant combination strategies.
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