Abstract 7288: Evaluation of silica spin-column and bead formats for rapid promoter DNA methylation analysis by qMSP in clinical and point-of-care settings
Authors: Fernando Zamuner, Ashley Ramos-Lopez, Amanda Garcia-Negron, Ana Purcell-Wiltz, Andrea Cortes-Ortiz, Aniris Roman, Keerthana Gosala, Eli Winkler, David Sidransky, Mariana Brait, Rafael E. Guerrero-Preston
Journal: Cancer Research (2024)

Abstract Late-stage cancers often lack effective management and treatment options, emphasizing the importance of early diagnosis for better prognosis and lower mortality rates. Molecular markers, such as DNA methylation tests, have shown promise in predicting and detecting cancer at its earliest stages. The COVID-19 post-pandemic scenario is providing a one in one-hundred-year opportunity of utilizing the excess installed PCR capacity world-wide to develop novel Quantitative Methylation Specific PCR (qMSP) screening strategies for cervical cancer screening in low-resource settings. This study aimed to compare the use of commercial bisulfite conversion kits in cervical epithelium liquid cytology samples (liquid cytology) from cancer screening clinics in the United States. Commercially available rapid bisulfite conversion protocols using silica spin column and magnetic beads were compared with conventional DNA extraction followed by bisulfite conversion protocols to profile DNA methylation by qMSP in a panel of methylated genes we previously developed to distinguish normal and cervical cancer patient samples. The results revealed that small sample volumes are suitable for methylation studies. Comparisons among four spin-column kits showed no significant differences in β-actin Cycle Threshold (Cts) values between Abcam, Epigentek, QIAGEN and Zymo D5021 kits. Zymo The best performing spin-column kit was compared with manual and automated versions of magnetic bead kits using a 96-well plate format for higher throughput. Methylation profiling of three genes (β-actin ZNF516, and FKBP6) with manual and automated magnetic bead kits revealed that automation increases throughput without a reduction in amplification efficiency in open PCR systems. Cost analysis showed that the direct kits 96-well plate format were more affordable compared to the Gold Standard manual protocol that uses spin-columns. An optimized version of Zymo D5046 magnetic bead kit provides the fastest turnaround time with similar amplification efficiency, when compared to spin-column or other magnetic bead kits. The test cost per sample is $5.41 dollars to process 83 samples in a 96 well-plate format in less than 2 hours. Another significant finding was showing the feasibility of using as low as 12µL of liquid cytology samples for DNA methylation testing, proving that bodily fluids are a liquid biopsy alternative to plasma. Overall, this comprehensive comparison is useful in determining optimal options for efficient and cost-effective cancer DNA methylation diagnostic tests, particularly in low-resource settings. Citation Format: Fernando Zamuner, Ashley Ramos-Lopez, Amanda Garcia-Negron, Ana Purcell-Wiltz, Andrea Cortes-Ortiz, Aniris Roman, Keerthana Gosala, Eli Winkler, David Sidransky, Mariana Brait, Rafael E. Guerrero-Preston. Evaluation of silica spin-column and bead formats for rapid promoter DNA methylation analysis by qMSP in clinical and point-of-care settings [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7288.