Spatially resolved and multiplexed MicroRNA quantification from tissue using nanoliter well arrays

Spatially resolved gene expression patterns are emerging as a key component of medical studies,including companion diagnostics,but technologies for quantification and multiplexing are limited.We present a method to perform spatially resolved and multiplexed microRNA(miRNA)measurements from formalin-fixed,paraffin-embedded(FFPE)tissue.Using nanoliter well arrays to pixelate the tissue section and photopatterned hydrogels to quantify miRNA,we identified differentially expressed miRNAs in tumors from a genetically engineered mouse model for non-small cell lung cancer(K-ras&(LSL-G12D/+);p53^(fl/fl)).This technology could be used to quantify heterogeneities in tissue samples and lead to informed,biomarker-based diagnostics.

Multi-layered control of PD-L1 expression in Epstein-Barr virus-associated gastric cancer

Gastric cancer(GC)is the fifth most common cancer worldwide.In approximately 10%of GC cases,cancer cells show ubiquitous and monoclonal Epstein-Barr virus(EBV)infection.A significant feature of EBV-associated GC(EBVaGC)is high lymphocytic infiltration and high expression of immune checkpoint proteins,including programmed death-ligand 1(PD-L1).This highlights EBVaGC as a strong candidate for immune checkpoint blockade therapy.Indeed,several recent studies have shown that EBV positivity in GC correlates with positive response to programmed cell death protein 1(PD-1)/PD-L1 blockade therapy.Understanding the mechanisms that control PD-L1 expression in EBVaGC can indicate new predictive biomarkers for immunotherapy,as well as therapeutic targets for combination therapy.Various mechanisms have been implicated in PD-L1 expression regulation,including structural variations,post-transcriptional control,oncogenic activation of intrinsic signaling pathways,and increased sensitivity to extrinsic signals.This review provides the most recent updates on the multilayered control of PD-L1 expression in EBVaGC.