Figure 1

Morphological quality comparison between FFPE, HOPE, and fresh-frozen specimens. a. Representative HE stained sections of FFPE, HOPE, and fresh frozen material. Tissue sections of HOPE fixed prostate cancer specimens show a 'FFPE -like' morphology. As expected, frozen tissue displayed typical indistinct cytomorphology. b. Representative p63 antibody immunohistochemistry staining of FFPE, HOPE, and fresh frozen material. FFPE and frozen sample display benign glands and infiltrating prostate cancer glands. The HOPE sample depicts infiltrating tumor glands and an intraductal spread of the prostate cancer. In the FFPE and frozen samples, the p63 antibody highlights the basal cells of the normal prostatic glands. In the HOPE sample, the p63 antibody highlights the basal cells of the gland with intraductal tumor spread. In all samples, the infiltrative prostate cancer glands are negative for p63 staining. The efficient binding specificity and signal strength of all samples is comparable, while the histomorphologic quality is inferior in the frozen sample. c. Representative Fluorescence in-situ hybridisation of ERG rearrangement on FFPE, fresh frozen and HOPE tissue sections. High power magnification. FISH for ERG on formalin-fixed, paraffin-embedded prostate cancer tissue. As expected for fresh-frozen samples, signals are specific, but the tissue section exhibits a typical freeze-related clumping of cells with a lack of distinct morphology. On the other hand, FISH for ERG on HOPE fixed prostate cancer tissue show a 'FFPE-like' signal specificity and morphology.