Direct bisulphite conversion of cervical samples for DNA methylation analysis.

Area of Science:

• Epigenetics
• Molecular Biology
• Gynecologic Oncology

Background:

• Sodium bisulphite conversion is a standard technique for DNA methylation analysis, differentiating methylated from unmethylated cytosines.
• Current methods often require DNA isolation prior to bisulphite conversion, adding steps to the workflow.

Purpose of the Study:

• To evaluate a direct cell conversion protocol for cervical samples as an alternative to using isolated genomic DNA.
• To assess the technical and analytical performance of direct cell conversion in methylation analysis.

Main Methods:

• Clinician-collected cervical samples (n=120) underwent either direct cell conversion or DNA isolation followed by bisulphite conversion.
• Quantitative methylation-specific PCR (QIAsure Methylation Test) was used to analyze methylation levels of FAM19A4 and miR124-2 genes and the ACTB control gene.

Main Results:

• The direct conversion protocol achieved a high success rate, with 119/120 (99.2%) samples yielding valid test results.
• Significant correlations were observed in ΔΔCq values for FAM19A4 and miR124-2 between the direct and isolated DNA protocols (Spearman Rho 0.708 and 0.763, respectively, p<0.001).
• Bland-Altman plots confirmed agreement between the two bisulphite conversion protocols.

Conclusions:

• The direct cell conversion protocol demonstrates good technical and analytical performance for cervical sample methylation analysis.
• This streamlined workflow offers a simplified and efficient alternative to conventional methods requiring DNA isolation.
• The protocol is suitable for routine epigenetic analysis in clinical settings.