Chai Jiaxin, Leng Dongni, Guo Shuwei, Zhang Rusong, Wang Jiandong, Gu Yun, Rao Qiu
Department of Pathology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210002, China.
Department of Pathology, Nanjing JunXie Hospital, Nanjing, 210002, China.
J Ovarian Res. 2025 Jul 2;18(1):140. doi: 10.1186/s13048-025-01729-9.
Ovarian cancer ranks as the eighth most common malignancy in women globally. Early detection remains a critical challenge for improving ovarian cancer diagnosis and treatment outcomes. Our prior study demonstrated that ARHGAP40 downregulation in basal cell carcinoma is attributed to CpG island hypermethylation. However, the expression and methylation status of ARHGAP40 in ovarian cancer remain unexplored. Here, we investigated ARHGAP40 protein expression in normal fallopian tubes, ovarian benign tumors, borderline tumors, low-grade serous carcinoma (LGSC) and high-grade serous carcinomas (HGSC). Methylation analysis of the ARHGAP40 was performed using bisulfite sequencing PCR (BSP). MethyLight assays were developed to detect methylated circulating tumor DNA (ctDNA) fragments of ARHGAP40. IHC results revealed absent or weak ARHGAP40 protein expression in 93.8% (30/32) of HGSC, 11.1% (2/18) of borderline tumors, and in 14.3% (1/7) of LGSC cases. ARHGAP40 protein expression was robust expressed in all normal fallopian tubes (15/15) and benign ovarian tumors (8/8). CpG island hypermethylation in the ARHGAP40 promoter showed a strong inverse correlation with protein expression (P < 0.001). Furthermore, methylated ctDNA for ARHGAP40 was detected in 80.0% (4/5) of HGSC patients' plasma, but not in benign tumor (0/3) and healthy controls (0/15). Our findings suggest that promoter hypermethylation may be a mechanism underlying ARHGAP40 silencing in HGSC. Detection of methylated ARHGAP40 ctDNA may serve as a noninvasive biomarker for early diagnosis and monitoring of HGSC. While our findings suggest the potential of methylated ARHGAP40 as an early diagnostic biomarker, the small sample size warrants validation in larger cohorts.
卵巢癌是全球女性中第八大常见恶性肿瘤。早期检测仍然是改善卵巢癌诊断和治疗结果的关键挑战。我们之前的研究表明，基底细胞癌中ARHGAP40的下调归因于CpG岛高甲基化。然而，ARHGAP40在卵巢癌中的表达和甲基化状态仍未得到探索。在此，我们研究了ARHGAP40蛋白在正常输卵管、卵巢良性肿瘤、交界性肿瘤、低级别浆液性癌（LGSC）和高级别浆液性癌（HGSC）中的表达情况。使用亚硫酸氢盐测序PCR（BSP）对ARHGAP40进行甲基化分析。开发了甲基化荧光定量分析方法来检测ARHGAP40的甲基化循环肿瘤DNA（ctDNA）片段。免疫组化结果显示，93.8%（30/32）的HGSC、11.1%（2/18）的交界性肿瘤以及14.3%（1/7）的LGSC病例中ARHGAP40蛋白表达缺失或微弱。ARHGAP40蛋白在所有正常输卵管（15/15）和卵巢良性肿瘤（8/8）中均有强烈表达。ARHGAP40启动子中的CpG岛高甲基化与蛋白表达呈强烈负相关（P < 0.001）。此外，在80.0%（4/5）的HGSC患者血浆中检测到了ARHGAP40的甲基化ctDNA，但在良性肿瘤（0/3）和健康对照（0/15）中未检测到。我们的研究结果表明，启动子高甲基化可能是HGSC中ARHGAP40沉默的潜在机制。检测甲基化的ARHGAP40 ctDNA可作为HGSC早期诊断和监测的非侵入性生物标志物。虽然我们的研究结果表明甲基化的ARHGAP40作为早期诊断生物标志物具有潜力，但样本量较小，需要在更大的队列中进行验证。
