Tissue array is a well-established technique that connects basic research with clinical applications and allows for the validation of many pathobiologic events from gene expression dysregulation to genomic aberrations. However, conventional tissue array has several limitations such as poor representation of tissue heterogeneity, destruction of donor tissue blocks due to coring, and usage of particular specimens that have limited evaluable material (tissue from thin specimens or needle biopsies). ObjecTIVE: To show the noninferiority and superiority of the new technique named Spiral Array-which allows for improved representation of the donor tissue while keeping the architectural details of the donor block intact-to that of the conventional tissue array. We compared the morphologic features of both methods.
We created both Spiral Array and conventional tissue array for 25 lung adenocarcinomas and 50 multiple tumors of various organs. The degree of coverage of tissue heterogeneity was examined by observing the range of the staining intensity differences in immunohistochemistry, using cytokeratin 7 and epidermal growth factor receptor (EGFR); the degree of morphologic preservation was tested by level of accurate prediction among 3 pathologists of the histopathologic diagnosis and organ type.
The Spiral Array showed better representations of the range of staining intensity for EGFR (P  =  .01). The level of accuracy for predicting organ type was significantly higher in Spiral Array than conventional tissue array (P  =  .047), whereas it was not significantly different between the 2 techniques for the histologic diagnosis.
Our data indicate that Spiral Array has benefits for covering tissue heterogeneity and preserving better morphology.