Identification of Malignancy in PAP Smear Samples Using the CGB3 and NOP56 Genes as Methylation Markers

Although various improvements have been made in the reporting of the Papanicolaou (PAP) test in recent years, there remain several challenges that have yet to be addressed in terms of determining a standardized methodology for categorizing atypical squamous cells of undetermined significance (ASC US).

The present study focuses on evaluating the performance of the methylation status of two genes (CGB3 and NOP56) using a total of 200 PAP samples, which were divided into the "determined" group, with 78 samples based on cytology, and the "undetermined" group (ASC US), with 122 samples. The promoter methylation status of the CGB3 and NOP56 genes was detected for the 200 PAP samples using methylation specific PCR (MSP). The diagnostic abilities of the CGB3 and NOP56 genes in PAP samples were measured, and receiver operating characteristic (ROC) curves were generated using Python programming language.

Based on the validation of CGB3 and NOP56 methylation in the 200 PAP samples, both genes exhibited higher methylation percentages in abnormal samples compared with normal samples. In addition, on the basis of diagnostic performance analysis, the CGB3 gene exhibited the highest sensitivity and specificity in both histology based ASC US and cytology based 'determined' PAP samples, with significant diagnostic abilities [area under the curve (AUC) values of 0.83 and 0.74, respectively, where AUC ≥0.5 was determined to be significant] to distinguish between the "normal" and "abnormal" samples.

The findings of the present study will contribute toward identifying a DNA methylation marker for the early detection of abnormal samples before they reach the initial stages of cervical cancer, and should prove to be helpful for clinicians in terms of diagnosing patients whose cells are ASC US.
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