Fig 1: Intraoperative CD24-targeted fluorescence imaging of four heterogeneous PDX of advanced stage HGSOC. (a) Intraoperative white light (colour), near infrared (NIR 800) fluorescent and pseudo-coloured fluorescence intensity merge images show positive identification of primary tumour and small metastatic lesions in four separate, orthotopically implanted PDX models of HGSOC, after injection with 3 µg/g CD24-AF750 48 h prior to intraoperative fluorescence imaging. Ex vivo optical imaging confirmed fluorescence specificity. Positive lesions are represented by dashed lines in the colour view image. The arrow points to the strongest fluorescent signal in the near infrared (NIR) 800 images. (Scale bar, 1 cm). (b) CD24 expression was confirmed by IHC in fluorescence positive PDX lesions. CD24 staining was evaluated in all five resected lesions with an immunoreactivity score (4•4 ± 1•1, scale: low 1 – 7 high). CK8 staining was used to confirm human tumour origin. Magnification 200×. (c) CD24 and folate receptor alpha IHC immunoreactivity score comparison on PDX tissue sections, demonstrating no significance (p > 0•05, Mann–Whitney U test)) difference (n = 21). Images were captured at 100× and 200× magnification (scale bar = 25 µm).