Tissue microarrays are reliable tools for the clinicopathological characterization of lung cancer tissue.

BACKGROUND The advantage of tissue microarray (TMA) is its ability to efficiently analyze large numbers of tissue specimens in a methodologically uniform way. The reliability of TMAs, especially with regard to clinicopathological characterizations, when compared to conventional immunohistochemistry (IHC) was evaluated. MATERIALS AND METHODS Seventy-two embedded tissue sections from lung cancer specimens were stained with monoclonal antibodies against the tumor-associated markers TA-MUC1 and Lewis Y. Three representative cores of every tumor were embedded in a paraffin array multiblock. The IHC was evaluated by the immunoreactive score (IRS). RESULTS The data for the TMA IHC and the conventional IHC were concordant (kappa > or = 80%) for both markers. Likewise, discordance (McNemar's test) was low, and sensitivity and specificity were above 80% for both markers. In the samples with high positive expression, the concordance increased (kappa > or = 90%), discordance disappeared (McNemar p = 1.0), and sensitivity and specificity increased above 90% for both markers. Using Cox regression models, all the clinicopathological dependencies were equivalent for both techniques and both markers. CONCLUSION Immunohistochemistry with tissue microarrays is valid and provides results equivalent to conventional immunohistochemistry with respect to expression patterns and clinicopathological characterizations.