Beecher tissue arrayer

The tissue microarray (TMA) was constructed from paraffin-embedded blocks of 30 paired invasive ducal carcinoma cases using a Beecher tissue arrayer (Beecher Instruments Inc., Sun Prairie, WI, USA). In brief, donor blocks were prepared after a thorough evaluation of hematoxylin and eosin-stained slides. One representative section of tumor or normal tissue for each cancer case was selected after the identification of representative tumor areas in each whole-mount slide. A single core (0.6 mm in diameter) was punched from the selected part of each donor block, using a specific orientation and placed into a pre-molded recipient paraffin wax block. Consecutive 4-μm-thick sections were cut from the recipient blocks and placed onto adhesive-coated slides for IHC analysis.

Tissue paraffin blocks were sectioned and stained with hematoxylin and eosin (HE). To prepare the tissue arrays (10×8 mm), eight holes (2 mm in diameter) were created using Beecher Tissue Arrayer (Beecher Instruments, Inc., Sun Prairie, WI, USA) on a control block, and filled up with tissues obtained from the donor blocks according to positions precisely mapped on HE film. The identification number of the tissue was recorded for each hole. For each sample, tumor and paracancerous normal (3–5 cm away from the tumor tissue) tissues were used. The arrays were sectioned to a thickness of 3–4 μm, melted, stained with HE and examined by pathologists prior to subsequent analysis.