Fig. 1: Subtypes of gastric cancer tumors and resulting PDX.

Patient tumors and PDX were investigated for histology and both ACRG (MSI, MSS/EMT, MSS/TP53⁺ and MSS/TP53⁻) and TCGA (MSI and EBV, the remaining MSS tumors were considered as GS or CIN) molecular subtypes. MSI status was determined using the pentaplex PCR (patient tumors) or by MLH1 loss as surrogate marker for the PDX (see Supplementary Fig. 1). MSS/EMT signature was determined by assessing the CDH1 mRNA expression, and the TOP2A, MKI67 mRNA expression as markers of proliferation by quantitative real-time PCR. The remaining MSS tumors were classified as MSS/TP53⁺ and MSS/TP53⁻ using a two-gene TP53 activation signature (MDM2 and CDKN1A expressions). EBV-positive tumors were detected by using quantitative PCR.