Hypodermic Needle Without Recipient Paraffin Block Technique

Abstract

This technique allows building TMA blocks with more than 300 tissue cores without using a recipient paraffin block for the tissue cores and without using a commercial TMA builder instrument. It is based on the construction of TMA needles modifying conventional hypodermic needles to punch tissue cores from donor blocks. Tissue cores are punctured from donor blocks and attached by double-sided adhesive tape on a computer-generated paper grid used to align the cores on the block mold, which is filled with liquid paraffin. TMA blocks constructed using this method can be utilized as positive and negative controls for immunohistochemistry, histochemistry and other techniques, interlaboratory quality control and also in research, but never for diagnosis purposes. This technique has the following advantages: it is easy to reproduce, affordable, quick, and creates uniform blocks with more than 300 cores aligned, at the same plane, adherent, and easy to cut, with negligible losses during conventional cutting and technical procedures.

Microarrays in Diagnostics and Biomarker Development

“…Likewise, the hypodermic needle technology does not require specific equipment (Pires et al 2006;Pires and de Souza 2010). Hollow needles of standard diameters are made from customized commercial 16-21-gauge needles with inner diameters between 0.5 and 1.2 mm, where the original bevel is removed and the inner surface is sharpened.…”