1. ¹Department of Pathology, Ohio State University, Columbus, Ohio
2. ²Department of Pathology, LDS Hospital, Salt Lake City, Utah
3. ³Radiation Therapy Oncology Group, Statistical Unit, Philadelphia, Pennsylvania
4. ⁴Department of Radiation Oncology, New York University Medical Center, New York, New York
5. ⁵Department of Radiation Oncology, Columbia Presbyterian Medical Center, New York, New York
6. ⁶Griffin Corporation, Seattle, Washington
7. ⁷Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
8. ⁸Department of Radiation Oncology, University of Washington Medical Center, Seattle, Washington
9. ⁹Department of Radiation Oncology, St. Joseph Mercy Hospital, Ann Arbor, Michigan

Correspondence: M. Elizabeth H. Hammond, M.D., Department of Pathology, LDS Hospital. 8th Avenue and "C" Street, Salt Lake City, UT 84143; e-mail: ldehammo@ihc.com; fax: 801-408-5020.

Accepted 21 August 2002.

Abstract

Tissue micro-arrays have been used for molecular and immunohistochemical studies. We sought to evaluate whether such arrays could substitute for whole sections in correlative studies performed by the Radiation Therapy Oncology Group. Four multitumor 150-sample arrays were built using formalin-fixed, paraffin-embedded, archival prostate, brain, and head/neck tumor blocks from RTOG tissue bank. p53 immunostaining of arrays and whole sections was done. Blind evaluation of each slide was made, and agreement rates between the two techniques were determined in various scenarios. Cost was also evaluated. Results demonstrate excellent agreement for p53 between slides and arrays. Agreement improved when three or four replicate arrays were used. Findings based on one to four arrays agree well with those obtained from analysis of the whole tissue samples. Minimal tissue damage, improved tissue salvage, cost reduction, ease of interpretation, and significant time savings were realized by using the arrays. Tissue micro array technique is a valuable tool for evaluation of patient materials associated with clinical trials.