Fig. 4.

Fluorescence imaging of high-grade serous ovarian cancer patient-derived xenograft (PDX) models using CD24-AF680. (a) Fluorescence imaging enables the detection of tumour progression in subcutaneous PDX models. Linear regression analysis showed correlation (r² = 0•96) of tumour size to fluorescence intensity. (b) Orthotopic implanted PDX models (n = 4) were imaged 24 h after CD24-AF680 injection (2 μg/g). Primary tumour lesions and metastases were detected by fluorescence optical imaging in vivo and (c) ex vivo. (d) Immunohistochemical (IHC) and H&E staining of the primary tumour and metastases confirmed CD24 expression and human tumour origin. Scale bars: original magnification of x400 mm (e) Monthly longitudinally fluorescence imaging illustrates linear increase in mean fluorescence intensity in orthotopic PDX models. IHC CD24 staining (scale bars: original magnification of x400 mm) and ex vivo imaging (scale bar 1 cm) confirmed high CD24 expression and tumour growth in the ovary and liver (staining index 9 and 6, respectively; scale: negative 0 – 9 high). Images are presented with the minimum to maximum fluorescence intensity for each mouse (p/s/cm²/sr). GI = gastrointestinal tract.