Published online Nov 15, 2019. doi: 10.4251/wjgo.v11.i11.933
Peer-review started: June 19, 2019
First decision: July 31, 2019
Revised: August 1, 2019
Accepted: August 20, 2019
Article in press: August 21, 2019
Published online: November 15, 2019
Processing time: 154 Days and 22.2 Hours
With recent advances in molecular pathology and the development of new chemotherapy regimens, the knowledge of the molecular alterations of pancreatic ductal adenocarcinoma (PDAC) is becoming appealing for stratifying patients for prognosis and response to a defined treatment. Archival formalin-fixed, paraffin-embedded samples are a useful source of genomic deoxyribonucleic acid; nevertheless, most studies employed formalin-fixed, paraffin-embedded samples deriving from surgical specimens, which are therefore representative of <20% of PDAC patients. Indeed, the development of a reliable methodology for endoscopic ultrasound-guided tissue acquisition, stabilization, and analysis is crucial for the development of molecular markers for clinical use in order to achieve “personalized medicine”. With the development of new needles, this technique is able to retrieve a high quantity and quality of PDAC tissue that can be used not only for diagnosis but also for mutational and transcriptome evaluations and for the development of primary cell or tissue cultures. In the present editorial, we discuss the current knowledge regarding the use of endoscopic ultrasound as a tool to obtain samples for molecular analyses, its possible pitfalls, and its use for the development of disease models such as xenografts or organoids.
Core tip: Surgical formalin-fixed, paraffin-embedded samples are not representative of all pancreatic ductal adenocarcinoma patients and it has been proven that “pre-resection” fine-needle aspiration smears are a better DNA source. Therefore, endoscopic ultrasound (EUS) is the recommended method for obtaining a tumor’s molecular signature. However, important limitations of EUS-acquired samples are: Intratumoral heterogeneity, total amount of tumoral cells, and lesional-to-non-lesional cell ratio. Furthermore, sample handling and storage conditions might affect the efficiency of DNA and even more RNA extraction. The possibility to obtain sufficient material from EUS to generate patient-derived xenografts or organoids is also a “hot topic”. Thus, optimization and standardization of procedures for EUS-guided biopsy and molecular analyses are essential to allow “precision medicine” for pancreatic ductal adenocarcinoma.