DNA quality assessment for array CGH by isothermal whole genome amplification

Area of Science:

• Genomics
• Molecular Biology
• Biotechnology

Background:

• Formalin-fixed paraffin-embedded (FFPE) tissues are a valuable source for DNA analysis, but DNA quality can be variable.
• Array Comparative Genomic Hybridization (array CGH) is a powerful technique for detecting genomic imbalances, but its success depends on high-quality DNA input.
• Current methods for assessing FFPE DNA quality for array CGH are often unreliable, leading to experimental failures and increased costs.

Purpose of the Study:

• To develop and validate a reliable method for predicting array CGH outcome using FFPE DNA.
• To evaluate the efficacy of isothermal DNA amplification as a predictor of array CGH quality.
• To determine if amplified FFPE DNA can be directly used for array CGH analysis.

Main Methods:

• DNA quality was assessed using isothermal amplification across various FFPE and fresh frozen tissue samples, including gastric cancer, colorectal cancer, uvula, and head and neck squamous cell carcinoma (HNSCC).
• Beta-globin PCR was used as a comparative method for DNA quality testing in gastric cancer samples.
• Array CGH was performed on both amplified and non-amplified DNA to compare results and assess the impact of amplification on copy number variation detection.

Main Results:

• Isothermal amplification accurately predicted DNA quality for array CGH in colorectal carcinoma, HNSCC, and uvula samples.
• Compared to PCR product lengths, isothermal amplification was more effective in selecting high-quality DNA for array CGH in gastric cancer samples.
• Array CGH performed on amplified FFPE DNA yielded identical chromosomal copy number change patterns as those obtained from non-amplified DNA, including fresh samples.

Conclusions:

• Isothermal DNA amplification serves as a dependable predictor of array CGH quality when using FFPE-derived DNA.
• The amplification product generated through isothermal amplification is suitable for direct use in array CGH analysis.
• This method enhances the reliability of array CGH on FFPE samples, overcoming limitations associated with DNA quality assessment.