Making and using inexpensive manually constructed tissue micro-array: experience of a tertiary care hospital in India

Tissue micro-array enables the analysis of a large number of tissues simultaneously. Widespread use of this technology is hampered by the high cost of commercial array instruments. We describe our experience of constructing tissue micro-array in a simple method using easily available and inexpensive instruments.

We used an 11-19 gauge (G) bone marrow trephine biopsy needle/ small sized slotted screwdriver to punch holes in the wax blocks. Cores were taken from donor tissue blocks using a bone marrow trephine biopsy needle and arrayed into host paraffin wax blocks. A detailed database was constructed for each array constructed.

The array blocks were used over a period of one year as internal control for immunohistochemistry (IHC), quality control and research. It took about 10 minutes to construct a nine-dot array and about one hour for a 56-dot array. During IHC, the average loss of control dots was less than one per cent. We did not see any loss of antigenicity in the control sections even after four weeks storage.

Tissue array construction by the technique described here is inexpensive and reliable alternative to automated instruments. Because it is easy to modify the arrays by varying the core size, it is easy to adapt this to individual labs and requirements. We recommend using blocks with cores in 3 x 3 to 5 x 4 grids as controls in IHC and for standardizing antibodies and array blocks with a larger number of cores for research.