Fig. 3: Regeneration and growth of EC PDXOs expressing FGFR2c are independent of exogenous growth factors but dependent on endogenous FGF2.

a Representative images of EC PDXO59 (upper panel), PDXO67 (middle panel) and PDXO56 (lower panels) cultured for 14 days in standard organoid media with the indicated withdrawal of growth factors and treatment with neutralising anti-FGF2 antibody alone or in combination with FGFR inhibitor (BGJ398). b Quantitation of relative growth reduction in three PDXOs cultured with the indicated withdrawal of growth factors or treatment with anti-FGF2 neutralising antibody, BGJ398 and both anti-FGF2 neutralising antibody and BGJ398. This experiment was performed in independent biological triplicate using independent PDXOs established from three different mice carrying each PDX. Organoid counting was performed by capturing 3 independent fields at a 10X microscopic objective view of each experiment. The error bar indicates the standard error of the mean (SEM) of the biological triplicates. Significance was assessed using a one-way ANOVA with Dunnett’s multiple comparison test. * P < 0.01, ** P < 0.001, **** P < 0.00001. c Representative IHC images showing expression of FGF2 in primary tumours and corresponding PDX and PDXO. d FGF2 IHC H-Score of primary patient tumour and matched PDXs and PDXOs. The scale bar indicates 200 µm for the PDXOs and 50 µm for the IHC. Ab antibody, PDX Patient-Derived Xenograft.