Tissue-print and print-phoresis as platform technologies for the molecular analysis of human surgical specimens: mapping tumor invasion of the prostate capsule.

Molecular profiling of human biopsies and surgical specimens is frequently complicated by their inherent biological heterogeneity and by the need to conserve tissue for clinical diagnosis. We have developed a set of novel 'tissue print' and 'print-phoresis' technologies to facilitate tissue and tumor-marker profiling under these circumstances. Tissue printing transfers cells and extracellular matrix components from a tissue surface onto nitrocellulose membranes, generating a two-dimensional anatomical image on which molecular markers can be visualized by specific protein and RNA- and DNA-detection techniques. Print-phoresis is a complementary new electrophoresis method in which thin strips from the print are subjected to polyacrylamide gel electrophoresis, providing a straightforward interface between the tissue-print image and gel-based proteomic techniques. Here we have utilized these technologies to identify and characterize markers of tumor invasion of the prostate capsule, an event generally not apparent to the naked eye that may result in tumor at the surgical margins ('positive margins'). We have also shown that tissue-print technologies can provide a general platform for the generation of marker maps that can be superimposed directly onto histopathological and radiological images, permitting molecular identification and classification of individual malignant lesions.