Spiral TMA, a Novel Technique To Make TMAs without Coring Tissue
J Fukuoka, T Uemura, T Tanaka, MD Hofer, S Kageyama, T Hori. Toyama University Hospital, Toyama, Japan; Brigham and Women's Hospital, Boston, MA
Background: Tissue microarrays (TMAs) are an established technique to bridge basic science research and clinical use allowing to determine the clinical significance of molecules. Yet, at the same time, conventional TMAs have several limitations such as tissue heterogeneity and frequent core loss due to uneven thickness of the donor block. To solve these problems, we developed a method, Spiral TMA (s-TMA). Here, we describe construction of spiral TMAs and demonstrate the concurrence of immunohistochemical staining results between s-TMA and conventional pathology specimens using the same blocks.
Design: For s-TMA, tissue is not cored from the donor block but thick slices of donor tissues reeled and arrayed as tissue cylinders. Major advantages are that tissue heterogeneity is represented, that TMAs from blocks with thin tissues layers can be constructed, the tissue loss from TMA slides due to the difference of tissue thickness is minimized and that the morphology of the array slide is visible before staining. Six cases were selected from case archives of Toyama University Hospital and 50 um thick specimens were cut from each case. Specimens were reeled and sectioned into cylinders 4 mm tall and arrayed in a recipient block with 3mm holes to form a s-TMA block. Five um thick specimens were cut from both TMA and original blocks and stained for Ki-67 which was evaluated by counting maximum and minimum percentage of positive cells at 40x.
Results: As listed in the table, Ki-67 staining was concurrent between s-TMA and conventional sections with agreement in maximum staining percentage between 100 35.5 % (median rate concurrence: 91.7%).
Table: Ki-67 in s-TMA and conventional slides.
|Table 1||Spiral TMA||Conventional tissue|
Conclusions: We introduce a newly developed technique, spiral TMA, that resolves some of the limitations encountered with convential TMAs. We validated its quality and accuracy of tissue representation. Our results further indicate that spiral TMA covers increased tissue heterogeneity, one of the major criticisms of conventional TMAs.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 210, Wednesday Afternoon