Molecular diagnostics of a single multifocal non-small cell lung cancer case using targeted next generation sequencing.

Histological and molecular subtyping of non-small cell lung cancer (NSCLC) is important for predicting survival and drug response in these patients. Up to 8 % of NSCLC are multifocal and these tumor foci are often clonally related. Multiple foci can however also represent different primary tumors, with prognostic and therapeutic consequences. We describe a patient with multifocal NSCLC from which we obtained tissue from two separate lesions. With routine conventional molecular determinations, the clonal relationship between the two lesions was determined. In addition, targeted next generation sequencing with the Ion Torrent Personal Genome Machine (PGM) was performed to explore the accuracy and additional value of this relatively new technique. The two tumors of this patient showed different activating epidermal growth factor receptor (EGFR) mutations, EGFR amplification status, TP53 mutation status, and loss of heterozygosity patterns. With the PGM, all conventional detected mutations were confirmed, and an additional variant of unknown significance in ATM was detected in one of the tumors. The multifocal NSCLC of this patient represents two unrelated primary tumors. Our results suggest that multifocal NSCLC should be considered as potentially multiple primary tumors. As the presence of activating EGFR mutations has important therapeutic consequences, EGFR testing should be performed on all tumor foci present. In the present case, targeted next generation sequencing using the PGM appeared to be accurate and comparable with conventional molecular determinations. However, the application of the PGM in routine pathology molecular diagnostics needs validation in larger series of cases.

Mistaken identity of widely used esophageal adenocarcinoma cell line TE-7.

Cancer of the esophagus is the seventh leading cause of cancer death worldwide. Esophageal carcinoma cell lines are useful models to study the biological and genetic alterations in these tumors. An important prerequisite of cell line research is the authenticity of the used cell lines because the mistaken identity of a cell line may lead to invalid conclusions. Estimates indicate that up to 36% of the cell lines are of a different origin or species than supposed. The TE series, established in late 1970s and early 1980s by Nishihira et al. in Japan, is one of the first esophageal cancer cell line series that was used throughout the world. Fourteen TE cell lines were derived from human esophageal squamous cell carcinomas and one, TE-7, was derived from a primary esophageal adenocarcinoma. In numerous studies, this TE-7 cell line was used as a model for esophageal adenocarcinoma because it is one of the few esophageal adenocarcinoma cell lines existing. We investigated the authenticity of the esophageal adenocarcinoma cell line TE-7 by xenografting, short tandem repeat profiling, mutation analyses, and array-comparative genomic hybridization and showed that cell line TE-7 shared the same genotype as the esophageal squamous cell carcinoma cell lines TE-2, TE-3, TE-12, and TE-13. In addition, for more than a decade, independent TE-7 cultures from Japan, United States, United Kingdom, France, and the Netherlands had the same genotype. Examination of the TE-7 cell line xenograft revealed the histology of a squamous cell carcinoma. We conclude that the TE-7 cell line, used in several laboratories throughout the world, is not an adenocarcinoma, but a squamous cell carcinoma cell line. Furthermore, the cell lines TE-2, TE-3, TE-7, TE-12, and TE-13 should be regarded as one single squamous cell carcinoma cell line.