Tissue microarrays are paraffin blocks containing multiple cyclindrical tissue biopsy cores taken from individual donor paraffin-embedded tissue blocks and placed into a recipient block with defined array coordinates. Tissue microarray technology facilitates rapid assessment of the clinical relevance of molecular markers by enabling the simultaneous analysis of hundreds of tissue specimens. One of the applications of this technology is to significantly accelerate advances in cancer research through more efficient assessment of novel markers of outcome and response and, as a result, a more rapid application of this knowledge to clinical practice.