Clinical application of targeted next-generation sequencing for colorectal cancer patients: a multicentric Belgian experience

International guidelines made RAS (KRAS and NRAS) status a prerequisite for the use of anti-EGFR agents for metastatic colorectal cancer (CRC) patients. Daily, new data emerges on the theranostic and prognostic role of molecular biomarkers; this is a strong incentive for a validated, sensitive, and broadly available molecular screening test. Next-generation sequencing (NGS) has begun to supplant other technologies for genomic profiling. We report here our 2 years of clinical practice using NGS results to guide therapeutic decisions.

The Ion Torrent AmpliSeq colon/lung cancer panel, which allows mutation detection in 22 cancer-related genes, was prospectively used in clinical practice (BELAC ISO 15189 accredited method). The DNA of 741 formalin-fixed paraffin-embedded CRC tissues, including primary tumors and metastasis, was obtained from 14 different Belgian institutions and subjected to targeted NGS.

Of the tumors tested, 98% (727) were successfully sequenced and 89% (650) harbored at least one mutation. KRAS, BRAF and NRAS mutations were found in 335 (46%), 78 (11%) and 32 (4%) samples, respectively. These mutation frequencies were consistent with those reported in public databases. Moreover, mutations and amplifications in potentially actionable genes were identified in 464 samples (64%), including mutations in PIK3CA (14%), ERBB2 (0.4%), AKT1 (0.6%), and MAP2K1 (0.1%), as well as amplifications of ERBB2 (0.3%) and EGFR (0.3%). The median turnaround time between reception of the sample in the laboratory and report release was 8 calendar days.

Overall, the AmpliSeq colon/lung cancer panel was successfully applied in daily practice and provided reliable clinically relevant information for CRC patients.

Esophagitis dissecans superficialis : a case series of 7 patients and review of the literature

INTRODUCTION

Esophagitis dissecans superficialis (EDS) is a rare desquamative disorder of the eso-phagus, characterized by sloughing of the superficial mucosa. It is a benign entity of uncertain etiology. Most cases of EDS are idiopathic but can be caused by medications, hot beverages, chemical irritants, celiac disease and many skin conditions.

AIM

Knowing that few case series have described this entity, we decided to review all the cases diagnosed in our center to characterize them.

METHODS

The pathological institutional database of Erasme University Hospital (Brussels, Belgium) was searched for the diagnosis of EDS. We reviewed retrospectively the clinical and endoscopic findings as well as histological features of all cases of EDS (Table 1). During this period of time, 21497 upper gastrointestinal endoscopies have been performed in our institution.

RESULTS

From January 2010 to September 2016, we identified 7 cases of EDS diagnosed in our institution in this time period. During the same period, 21497 upper gastrointestinal endoscopies were performed (incidence 0.03%). Endoscopic findings evoked in 2 patients a suspicion of an esophageal tumor; the first one was described as a raised detached lesion of the distal third of the esophagus with suspicion of squamous cell carcinoma (Fig. 1) and the second as a suspected tumor of the proximal third of the esophagus (Fig. 2). For other patients, EDS was misdiagnosed as unspecific esophagitis in 2, reflux or mycotic esophagitis in 2. Only one patient was suspected to have sloughing esophagitis.Histologic features present in all of those cases were characterized by the presence of a sloughing and necrosis of the superficial layer of the esophageal squamous epithelium with negative anti HSV and anti CMV antibodies, negative periodic acid Schiff stain for fungal infections as well as absence of signs of dysplasia or signs of malignancy. In 2 patients, there was a presence of multiple bacterial colonies on the superficial epithelium. Acute inflammation was reported in 4 of the patients with the presence of eosinophils in the superficial epithelium described in 2 of these patients and of polymorphonuclear leukocytes in 2 other patients (Fig. 3).An endoscopic follow up 2 months after PPI treatment performed in 3 patients, 2 of them had an atypical endoscopic presentation with suspicion of a tumor on endoscopic examination showed a complete resolution of the esophageal lesions was observed in these patients.

CONCLUSION

EDS is a rare benign entity that endoscopists must be aware of in order not to mistake it for other entities such as esophagitis or squamous cell carcinoma. The diagnosis is based on biopsies. The prognosis is good after stopping the causative agent.

Clinical Application of Targeted Next Generation Sequencing for Colorectal Cancers

Promising targeted therapy and personalized medicine are making molecular profiling of tumours a priority. For colorectal cancer (CRC) patients, international guidelines made RAS (KRAS and NRAS) status a prerequisite for the use of anti-epidermal growth factor receptor agents (anti-EGFR). Daily, new data emerge on the theranostic and prognostic role of molecular biomarkers, which is a strong incentive for a validated, sensitive and broadly available molecular screening test in order to implement and improve multi-modal therapy strategy and clinical trials. Next generation sequencing (NGS) has begun to supplant other technologies for genomic profiling. Targeted NGS is a method that allows parallel sequencing of thousands of short DNA sequences in a single test offering a cost-effective approach for detecting multiple genetic alterations with a minimum amount of DNA. In the present review, we collected data concerning the clinical application of NGS technology in the setting of colorectal cancer.