Methylation of PAX1 gene promoter in the prediction of concurrent chemo-radiotherapy efficacy in cervical cancer

Reactivation of methylation-silenced PAX1 inhibits cervical cancer proliferation and migration via the WNT/TIMELESS pathway

Although aberrant methylation of PAX1 is closely associated with cervical cancer (CC), PAX1 methylation (PAX1m) and its role in CC remain to be elucidated. Here, we clarified the biological function of PAX1 in CC. First, PAX1m in ThinPrep cytologic test samples was measured via quantitative methylation-specific PCR. The results showed that PAX1 promoter methylation levels were significantly increased in CC patients (p < 0.001). We also found that PAX1 promoter methylation levels were positively correlated with tumor purity but negatively correlated with immune-infiltration via public databases. Then, CRISPR-based methylation perturbation tools (dCas9-Tet1) were constructed to further demonstrate that DNA methylation participates in the regulation of PAX1 expression directly. Gain- and loss-of-function experiments were used to show that PAX1 overexpression restrained proliferation, migration and improved cisplatin sensitivity by interfering with the WNT/TIMELESS axis in CC cells. Additionally, Co-immunoprecipitation assays further confirmed the interaction between PAX1 and TCF7L2. Taken together, our results suggested that a tumor suppressor role of PAX1 in CC and that CRISPR-based PAX1 demethylation editing might be a promising therapeutic strategy for CC.

Promising predictive molecular biomarkers for cervical cancer (Review)

Cervical cancer (CC) constitutes a serious public health problem. Vaccination and screening programs have notably reduced the incidence of CC worldwide by >80%; however, the mortality rate in low‑income countries remains high. The staging of CC is a determining factor in therapeutic strategies: The clinical management of early stages of CC includes surgery and/or radiotherapy, whereas radiotherapy and/or concurrent chemotherapy are the recommended therapeutic strategies for locally advanced CC. The histopathological characteristics of tumors can effectively serve as prognostic markers of radiotherapy response; however, the efficacy rate of radiotherapy may significantly differ among cancer patients. Failure of radiotherapy is commonly associated with a higher risk of recurrence, persistence and metastasis; therefore, radioresistance remains the most important and unresolved clinical problem. This condition highlights the importance of precision medicine in searching for possible predictive biomarkers to timely identify patients at risk of treatment response failure and provide tailored therapeutic strategies according to genetic and epigenetic characteristics. The present review aimed to summarize the evidence that supports the role of several proteins, methylation markers and non‑coding RNAs as potential predictive biomarkers for CC.

PAX1/JAM3 Methylation and HPV Viral Load in Women with Persistent HPV Infection

The relationship of PAX1/JAM3 methylation as well as HPV viral load (VL) with cervical lesions has been reported, but their role in persistent HPV infection without cervical high-grade lesions has not been fully elucidated. A total of 231 females diagnosed with persistent HPV infection and pathologically confirmed absence of high-grade cervical lesions were selected from the Colposcopy Outpatient Clinic of Peking University People's Hospital, from March 2023 to December 2023. They were categorized into two groups based on the duration of HPV infection: the HPV persistent less than 3 years group and the more than 3 years group. PAX1/JAM3 methylation and HPV VL were determined by real-time PCR and BioPerfectus Multiplex Real-Time (BMRT)-HPV reports type-specific VL/10,000 cells, respectively. The average age of individuals with HPV infection lasting more than 3 years was higher compared to those with less than 3 years (48.9 vs. 45.1 years), with a statistically significant difference. Among the participants, 81.8% (189/231) had no previous screening. The methylation levels of JAM3 and PAX1 were significantly higher in individuals with HPV infection persisting for more than 3 years compared to those with less than 3 years, with a statistically significant difference (p < 0.05). There was a significant correlation between PAX1 and JAM3 methylation (p < 0.001), which could be used as cumulative evidence of HPV infection duration before the occurrence of precancerous lesions. The incidence of vaginal intraepithelial lesions was higher in individuals with HPV infection persisting for more than 3 years compared to those with less than 3 years, and HPV VL can be used as an indicative biomarker for concurrent cervical-vaginal lesions, especially for HPV other than 16/18 genotypes.

Utilization of PAX1 methylation test for cervical cancer screening of non-HPV16/18 high-risk HPV infection in women

Aim: To evaluate the clinical performance of PAX1 methylation (PAX1m) and cytology for patients with non-HPV16/18 high-risk HPV (hrHPV) infection. Methods: Cervical exfoliated cells from 387 outpatients with non-HPV16/18 hrHPV - positive were collected for cytology and PAX1m assays. Results: The PAX1m level increased with the severity of cytology and histopathology. For cervical intraepithelial neoplasia (CIN)CIN2+/CIN3+, the areas under the curve were both 0.87. The specificity and positive predictive value (PPV) of PAX1m were greater than abnormal cytology (CIN2+ specificity: 75.5 vs 24.8%; PPV: 38.8 vs 18.7%; CIN3+ specificity: 69.3 vs 22.7%; PPV: 14.0 vs 6.7%). Conclusion: PAX1m increased specificity and PPV for CIN2+/CIN3+ compared with cytology for women with non-HPV16/18 hrHPV (+).

The role of PAX1 methylation in predicting the pathological upgrade of cervical intraepithelial neoplasia before cold knife conization

Objective

To explore the ability of PAX1 methylation (PAX1^m) to predict the pathological upgrade of cervical intraepithelial neoplasia (CIN) before cold knife conization (CKC).

Methods

A total of 218 women that underwent colposcopy-directed biopsy (CDB) pathology for the confirmation of CIN2 and CIN3 between December 2020 to September 2021 were enrolled in this study. The methylation levels of PAX1 (ΔCp_PAX1) were determined by quantitative methylation-specific polymerase chain reaction (qMSP). Receiver operating characteristic curve was used to identify the optimal cut-off value of ΔCp_PAX1 for predicting the pathological upgrade of disease.

Results

In the CDB-confirmed CIN2 group, 36% of CIN2 was found to have pathologically upgraded to CIN3 and 30% regressed to low-grade squamous intraepithelial lesion (LSIL) and below, and none of CIN2 upgraded to early-stage cervical cancer (ESCC) after CKC. In the CDB-confirmed CIN3 group, 19.5% (23/118) of CDB-confirmed CIN3 were pathologically upgraded to ESCC after CKC. Regardless of CIN2 or CIN3, the ΔCp_PAX1 level of women with upgraded pathology after CKC was significantly lower than that of women with degraded pathology. The optimal △Cp_PAX1 cut-off value in predicting CIN3 to be upgraded to ESCC after CKC was 6.360 and the area under the curve (AUC) was 0.814, with similar sensitivity (78.3%) and higher specificity (84.2%) than cytology≥LSIL (Se:78.3%;Sp:58.9%) and HPV16/18 positive (Se:73.9%;Sp:46.3%) patients.

Conclusions

PAX1^m could be a promising auxiliary marker in predicting the pathological upgrade of CIN before CKC. We found that if the △Cp _PAX1 cut-off value is lower than 6.360, it is highly suggestive of invasive cervical cancer.

Association and Effectiveness of PAX1 Methylation and HPV Viral Load for the Detection of Cervical High-Grade Squamous Intraepithelial Lesion

Background: PAX1 methylation (PAX1m) and HPV viral load (VL) have been reported to detect cervical high-grade squamous intraepithelial lesions (HSIL), but the relationship between them is unclear. This study aimed to evaluate the correlation between HPV VL and PAX1m and its effectiveness in predicting cervical lesions. (2) Methods: A total of 476 women referred to colposcopy for abnormal cervical screening at the Peking University People’s Hospital between November 2020 and November 2021 were enrolled. PAX1m and HPV VL were determined by QMSP and BMRT-HPV reports type-specific VL/10,000 cells, respectively. (3) Results: PAX1m was significantly increased in HSIL, especially in cervical cancer, but there was no significant difference between cervical intraepithelial neoplasms 1(CIN1) and CIN2. However, HPV VL significantly differed between CIN1 and CIN2 but not between CIN3 and cervical cancer. In general, PAX1m positively correlated with all hrHPV VL, mainly in the HPV16/18 VL (p < 0.001), but had no relationship with the other 12 types of hrHPV VL. PAX1m had the highest specificity in diagnosing CIN2+, followed by HPV16/18 VL, which are higher than cytology ≥ASCUS. (4) Conclusions: Hypermethylation of PAX1 is associated with high HPV VL, especially HPV16/18, and both present advantageous specificity in detecting CIN2+.

An overview of PAX1: Expression, function and regulation in development and diseases

Transcription factors play multifaceted roles in embryonic development and diseases. PAX1, a paired-box transcription factor, has been elucidated to play key roles in multiple tissues during embryonic development by extensive studies. Recently, an emerging role of PAX1 in cancers was clarified. Herein, we summarize the expression and functions of PAX1 in skeletal system and thymus development, as well as cancer biology and outline its cellular and molecular modes of action and the association of PAX1 mutation or dysregulation with human diseases, thus providing insights for the molecular basis of congenital diseases and cancers.