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Published on: January 22, 2013
Tissue microarrays from renal cell tumors: exclusion criteria and rate of exclusion
Martina Hager1, Christian Kolbitsch, Werner Tiefenthaler
1Department of Pathology, Paracelsus Medical University, Salzburg, Austria. hager.martina@gmx.at
Objectives:
Exclusion of tissue microarray (TMA) cores can cause the total loss of a tumor case, and this can have a potentially negative effect on the results of TMA-based studies. The main aim of this study was to evaluate the loss of informative cores having cut a given number of slices from a TMA block. A further objective was to investigate the effect in various subtypes of renal cell tumors and the detailed reasons for the loss of informative cores.
Material And Methods:
A TMA was constructed from renal tumor specimens (n=461). The cause and rate of exclusion were evaluated in the first slice (FS) and last slice (LS) (i.e. the 40th) cut from the TMA blocks. Furthermore, the overall case loss under the assumptions that only one, two or three cores per case were punched was extrapolated.
Results:
Sarcomatoid and papillary renal cell carcinomas showed the highest overall exclusion rate. Irrespective of the type of tumor, however, the case loss was approximately tripled from FS to LS. Furthermore, extrapolation showed that a reduction in the number of cores punched per case, for example by one, would further double the number of cases lost. Reasons for exclusion were mainly as follows: core loss; <25% tumorous tissue per core; core folding; and core with necrotic area.
Conclusion:
This study shows that punching at least three to four cores per case is advisable when constructing TMAs from oncocytoma and renal cell carcinoma specimens, and that the type of tumor has an effect on the cause and rate of core exclusion.
Insights
To minimize data loss in tissue microarray (TMA) studies, researchers should use at least three to four cores per case, especially for renal cell tumors. Punching fewer cores significantly increases the risk of losing entire tumor cases from analysis.
Area of Science:
- Oncology
- Pathology
- Biomedical Research
Background:
- Tissue microarrays (TMAs) are crucial for large-scale studies, but core exclusion can lead to the loss of entire tumor cases.
- This loss can negatively impact the reliability and statistical power of TMA-based research findings.
- Understanding core exclusion rates and reasons is vital for optimizing TMA construction.
Purpose of the Study:
- To evaluate the loss of informative cores when a specific number of slices are cut from a TMA block.
- To investigate how core exclusion rates vary across different subtypes of renal cell tumors.
- To identify the detailed reasons contributing to the loss of informative cores.
Main Methods:
- A tissue microarray (TMA) was constructed using 461 renal tumor specimens.
- The exclusion rate and causes were assessed in the first slice (FS) and the 40th slice (LS) of TMA blocks.
- Overall case loss was extrapolated based on punching one, two, or three cores per case.
Main Results:
- Sarcomatoid and papillary renal cell carcinomas exhibited the highest exclusion rates.
- Case loss approximately tripled from the first slice to the last slice, irrespective of tumor type.
- Reducing the number of cores per case, e.g., by one, could double the number of lost cases. Common exclusion reasons included core loss, insufficient tumor tissue (<25%), core folding, and necrotic tissue.
Conclusions:
- Punching a minimum of three to four cores per case is recommended for constructing TMAs from oncocytoma and renal cell carcinoma specimens.
- The specific tumor type influences the causes and rates of core exclusion.
- Optimizing core selection is essential to prevent case loss and ensure robust TMA study outcomes.
