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and unremarkable glands could be found. However, in
TMAs, despite the small tissue size, they have the most
representative tissue by obtaining two or three samples
from different regions of each “donor.” This point has also
been proved in previous studies by comparing immunohis-
tochemical findings on TMAs and their corresponding
“large” sections from solid cancer specimens [ 14 – 20 ].
●● TMA is a powerful tool for rapid screening of different
tumor types at the same type in research [ 21 ].
●● Standardization of experimental condition: (1) all the
slides of one TMA study are usually incubated within one
jar; (2) all TMAs have same concentrations and tempera-
tures of all reagents; (3) all the tissues of one study are
located on the same TMA slide. Thus, the ages of the tis-
sue section (time between sectioning and use) and section
thickness, and the exposure times for all steps are identical.
Despite extreme standardization within each experiment,
surprising intra-laboratory variations can sometimes occur
if experiments are repeated under slightly different condi-
tions. In TMA, however, all groups within one TMA (low
and high stage, good and poor prognosis) are evenly
affected by experimental changes and meaningful differ-
ences will still become detectable if different experimental
circumstances alter the threshold for the detection of
positivity.
Disadvantages
●● A sufficiently large amount of tissues on a TMA are impor-
tant to find significant associations in the case of subopti-
mal immunostaining at the time that they were removed
and fixed in buffered.
●● A cancer is big and is heterogeneous. TMA faces the chal-
lenges of not able to capture the expressions of protein/
gene by selecting a small portion of the cancer.
●● Furthermore, it needs expertise in setting up the TMA.
●● Technical difficulties in handling the small tissue in TMA
during transfer of the tissue using the small needle (in
automated methods).
●● The small tissue in TMA is more easy to be detached or
loss during cut-up and staining.
●● It is difficult and time consuming to interpret the features
of different tissues in the TMA. The slides need to be
scanned by scanning machine to make whole slide digital
image for proper assessment.Nassim Saremi and Alfred K. Lam