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Using 2-step PCR and restriction endonuclease digestion to detect K-ras mutation in paraffin-embedded tissues: is it
1Department of Internal Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.
Abstract:
In this study, we detected the existence of both wild type and mutant K-ras DNA on the cutting board and in the solutions for tissue processing in our pathology laboratory. The detection rate of K-ras mutant DNA inversely correlated with the frequency of the solution changed, implying that DNA contaminant including K-ras mutant may be accumulated while increasing specimens were processed. The exact routes of contamination during tissue processing remain to be determined. Nevertheless, this study unveils the possibility of DNA contamination in the laboratory that can be amplified by PCR analysis, and precaution should be taken while we interpret our PCR data from paraffin-embedded specimens. The work also highlights the necessity of contamination control procedures, including specific laboratory construction, environmental control, and strict hygiene standards for laboratory equipment and personnel. Moreover, fresh specimens seem more reliable than archival materials for PCR diagnosis.
Insights
Wild type and mutant K-ras DNA contamination was found in pathology lab tissue processing solutions. Increased specimen processing led to higher K-ras mutant DNA detection, highlighting the need for strict contamination control.
Area of Science:
- Molecular Biology
- Pathology
- Laboratory Science
Background:
- Polymerase chain reaction (PCR) is a powerful tool for DNA analysis.
- K-ras mutations are significant in various cancers.
- Accurate PCR results depend on preventing DNA contamination.
Purpose of the Study:
- To investigate the presence and potential sources of K-ras DNA contamination during routine tissue processing in a pathology laboratory.
- To assess the impact of tissue processing procedures on DNA contamination levels.
- To emphasize the importance of contamination control in molecular diagnostics.
Main Methods:
- Detection of wild type and mutant K-ras DNA using PCR.
- Analysis of DNA contamination in cutting boards and tissue processing solutions.
- Correlation of contamination rates with the frequency of solution changes and specimen processing volume.
Main Results:
- Both wild type and mutant K-ras DNA were detected in laboratory equipment and processing solutions.
- K-ras mutant DNA detection rates increased with higher specimen processing volumes and less frequent solution changes.
- The findings suggest accumulation of DNA contaminants during tissue processing.
Conclusions:
- DNA contamination, including K-ras mutants, is a significant concern in pathology laboratories performing PCR.
- Strict contamination control measures, including laboratory design, environmental controls, and hygiene, are essential.
- Fresh specimens are recommended over archival materials for reliable PCR-based diagnostics to mitigate contamination risks.