Introduction
Cervical intraepithelial neoplasia (CIN) is one of the precancerous lesions of cervical cancer, with a high malignant transformation rate, posing a potential threat to women's health [
1]. Despite cervical cytological screening and cervical biopsy being commonly used diagnostic methods clinically, the accurate diagnosis of early CIN and assessment of disease severity still present challenges [
2]. Netrin-1, as an important molecular signaling regulator, plays a crucial role in nervous system development [
3]. Recent studies [
4] have found that Netrin-1 expression levels are abnormal in various tumors and participate in tumorigenesis, development, and angiogenesis processes. However, the expression of Netrin-1 in cervical diseases and its relationship with disease severity have not been fully elucidated. Additionally, ultrasound blood flow parameters have important value in assessing tumor blood supply [
5]. Through Doppler ultrasound examination and related software analysis, blood flow parameters such as flow index (FI), vascularization index (VI), and vascularization flow index (VFI) can be obtained to objectively evaluate tumor blood supply [
6]. This study aims to explore the expression of Netrin-1 in CIN patients and analyze its correlation with ultrasonic blood flow parameters in disease severity assessment. Through retrospective analysis of clinical data of CIN patients and patients with chronic cervicitis, we attempt to validate whether Netrin-1 and ultrasonic blood flow parameters can serve as potential biomarkers and auxiliary diagnostic methods for early screening, diagnosis, and prevention of cervical cancer transformation. The results of this study are expected to provide new diagnostic and therapeutic insights for clinical practice, and offer more accurate evidence for early prevention and intervention of cervical cancer.
4. Discussion
Currently, the methods for clinical treatment of CIN mainly include cervical conization or physical therapy, although these methods can partially inhibit the development of CIN, the overall efficacy of treatment is not high [
9]. The condition of CIN often continues to deteriorate, and the risk of CIN grade III lesions developing into cervical cancer remains quite high [
10]. Research [
11] indicates that in endometrial diseases, endometrial invasion, neovascularization, and neural fiber proliferation all play important roles. Netrin-1 is a secreted protein with a molecular weight of 80 kD, its main function is to guide the growth and development of neuronal axons in specific directions through regulation by its receptors [
12]. However, due to the diversity of its receptors, the action of Netrin-1 can be either attractive or repulsive [
13]. Vascular and neural structures have anatomical similarities, and research [
14] suggests that fluoxetine can upregulate the expression of HIF-1α-Netrin/VEGF cascade proteins, thereby promoting angiogenesis and improving long-term functional recovery after ischemic stroke. Furthermore, research [
15] indicates that Netrin-1 can induce angiogenesis of endometrial lesions by interacting with CD146 in vascular endothelial cells, playing an important role in neurovascularization of endometriosis. Therefore, Netrin-1 not only promotes the proliferation of vascular endothelial cells but also promotes their migration and adhesion. In this study, we found that the expression of Netrin-1 was significantly increased in the cell membrane, cytoplasm, and cell-cell junctions of fibrous proliferative tissues. Compared with the control group, the positive expression rate of Netrin-1 protein in CIN patients in the observation group was significantly decreased, and with the worsening of the lesion, its expression rate showed a decreasing trend. This suggests that Netrin-1 may play an important protective role in the development of CIN, but its specific mechanism of action is unclear and requires further research for clarification. In addition, neurovascularization is crucial for the survival of metastatic tissues and metastatic tumors. Research [
16] indicates that interleukin-1 (IL-1), a pro-inflammatory cytokine secreted by macrophages, may regulate the generation of neural cells by stimulating ectopic endometrial stromal cells. Recent studies [
17] have also found that Netrin-1 can inhibit cell apoptosis by increasing the proportion of regulatory T cells and reducing the infiltration of T cells and macrophages, thereby reducing lung ischemia-reperfusion injury in mice. Therefore, we speculate that Netrin-1 may be involved in the physiological and pathological processes of vascular genesis and inflammatory response in CIN patients through different pathways. In conclusion, the treatment of CIN still faces challenges, and Netrin-1, as an important regulatory factor, may play a crucial protective role in the development of CIN. However, its specific mechanism is unclear and further research is needed for in-depth exploration.
In recent years, with the widespread application and development of Doppler ultrasound technology, its importance in the diagnosis and treatment of cervical lesions has gradually become prominent [
18]. Compared to traditional two-dimensional imaging, Doppler ultrasound detection can visually display abnormal blood flow signals within lesion or cancerous tissues, aiding in accurately distinguishing the blood flow situation of lesions, cancerous tissues, and surrounding tissues [
19]. Through computer software combined analysis, hemodynamic parameters such as FI, VI, and VFI can be directly obtained, which helps to better guide clinical treatment and analysis work. FI represents the total number of blood cells detected at the moment of three-dimensional scanning, VI represents the number of vessels detected at the lesion site, and VFI indicates the sum of all vascular information and blood cell counts detected at the lesion site [
20]. In the early diagnosis of cervical dysplasia and carcinoma, vaginal ultrasound, as an intracavitary ultrasound technique, has a high image resolution and can accurately detect abnormal blood flow signals within lesion foci, possessing high clinical utility. Multiple studies [
21,
22] have shown that in early cervical dysplasia and carcinoma, vaginal ultrasound can clearly display cervical layer structures, accurately analyze the infiltration of lesions or carcinomas and surrounding tissue conditions, and has high sensitivity. The results of this study showed that the Doppler ultrasound blood flow parameters FI, VI, and VFI values in the observation group were significantly higher than those in the control group. With the deepening of the lesion degree, FI, VI, and VFI values increased successively, indicating that compared with the control group, there is neoangiogenesis at the lesion site of CIN patients, and with the aggravation of the lesion degree, the number of neoangiogenesis increases, and blood flow perfusion enhances, which is consistent with previous related research results [
23]. Pearson correlation analysis results showed that Netrin-1 was negatively correlated with FI, VI, and VFI values. Further Logistic multivariate analysis showed that Netrin-1 positivity was a protective factor for CIN grade III lesions, while FI, VI, and VFI were risk factors for CIN grade III lesions. In addition, this study also preliminarily explored the predictive value of Netrin-1 expression and Doppler ultrasound blood flow parameters for the severity of cervical intraepithelial neoplasia. According to clinical ROC curve research results, when the AUC area is greater than 0.7, it indicates certain predictive value, and when the AUC area is greater than 0.85, it suggests higher predictive value. The results of this study showed that the AUC areas of Netrin-1 were 0.732, with a sensitivity of 76.4% and a specificity of 79.5%, higher than other indicators, indicating that Netrin-1 expression has a certain predictive value for predicting the severity of cervical intraepithelial neoplasia. Therefore, closely monitoring the dynamic changes of this indicator is of great significance for predicting and guiding timely clinical interventions.
In summary, CIN patients exhibit low expression of Netrin-1 and high expression of Doppler ultrasound blood flow parameters FI, VI, and VFI, which are closely related to the severity of the patient's condition. Netrin-1 is negatively correlated with Doppler ultrasound blood flow parameters FI, VI, and VFI. Netrin-1 positivity is a protective factor for CIN grade III lesions, while FI, VI, and VFI are risk factors for CIN grade III lesions. The expression levels of both have a certain predictive and guiding role in early screening, diagnosis, treatment, and prevention of cervical cancer. It is worth noting that although this study has achieved some positive results in analyzing the relationship and predictive value of Netrin-1 expression and Doppler ultrasound blood flow parameters with the severity of CIN, the study itself still has some limitations, such as: ① Small sample size: The relatively small sample size included in this study may limit the reliability and generalizability of the results; ② Retrospective study design: This study used a retrospective analysis method, which may have information bias and incomplete data issues, and cannot rule out the influence of other potential factors; ③ Failure to consider other relevant factors: In addition to Netrin-1 and Doppler ultrasound blood flow parameters, there may be other factors affecting cervical intraepithelial neoplasia, such as viral infections, genetic factors, lifestyles, etc., but this study did not fully consider these factors, which may affect the interpretation and inference of the results to some extent. Therefore, although this study has made some progress, further research and validation are still needed to refine and confirm its results, and promote its application in clinical practice.