Validation of tissue microarray technology using cervical adenocarcinoma and its precursors as a model system

The tissue microarray (TMA) technology has potentiated large-scale retrospective cohort studies using archival formalin-fixed, paraffin-embedded tissues. We used a large series of cervical adenocarcinomas to investigate TMA technology in assessment of immunohistochemical staining. A TMA was constructed using 273 archival paraffin blocks from 139 patients with 119 invasive and 20 adenocarcinoma in situ and 16 normal controls. Two paired cores were obtained from specific regions of donor blocks selected at histologic review and were arrayed into a recipient blocks. The novel array blocks and some whole donor blocks were sectioned and used for immunohistochemical analysis for carcinoembryonic antigen, cytokeratin 7, and cytokeratin 20 antibodies as potential diagnostic markers. We compared staining in the microarray disks with the whole tissue sections. Two paired TM cores were found to yield good immunohistochemical staining that was concordant with that of the whole section from which it originated in about 97% of cases, and the cores accurately represented the morphology of the tumor with respect to tumor typing and differentiation in all cases. Our results suggest that TMAs can be successfully used for immunohistochemical studies of cervical adenocarcinomas. The areas sampled from donor blocks must be selected by careful review of sections from the original blocks.