Miniature tissue microarrays for HercepTest standardisation and analysis.

AIMS To assess the practicality of using a miniature tissue microarray (TMA) with several examples of each HercepTest score from 0 to 3+ as a control for routine HercepTest immunohistochemistry. METHODS A TMA was constructed from in house cases of breast cancer where HercepTest on the whole sections showed scores 0, 1+, 2+, or 3+. The TMA, which measured 5 x 5 mm, was designed with four rows (each representing scores 0, 1+, 2+, and 3+), with five 0.6 mm cores from separate cases. In all, 20 individual cases were represented and the TMA took less than one hour to construct. Fifty sequential 4 microm sections were cut from the TMA to maximise the number of available sections. They were stored at 4 degrees C for 1-270 days and when a case needed HercepTest staining the section was added to the TMA tissue control slide. RESULTS All slides contained tissue spots and immunohistochemical staining was consistent throughout the time period. CONCLUSIONS The miniature TMA with examples of all HercepTest scores described here is an ideal tissue control and can be used as a visual reference for scoring a case. Slides stored at 4 degrees C could be used for up to 270 days.