The results of this study showed that patients with early-stage cervical cancer, for whom operation is considered a treatment option, can be classified using MRI into two groups based on the clarity of the tumor border. Moreover, it was shown that this classification may have prognostic importance. Tumor shape has been reported as a prognostic factor in other malignancies, such as breast cancer, bladder cancer, and meningioma8,9,10. To the best of our knowledge, this study is the first to examine the relationship between tumor border and prognosis in cervical cancer. MRI showed a significantly better diagnostic performance than clinical assessment for both overall staging and evaluation of prognostic factors11. As demonstrated in earlier reports, prognostic factors for cervical cancer are tumor size, patient age, stage, lymph node involvement and location, LVSI, histological type, and tumor grade12,13,14. However, some of these factors cannot be assessed unless the patient undergoes surgery. The current study revealed that the tumor border correlates with incidence of LVSI, postoperative upgrade in staging, lymph node metastasis, and distant metastasis. Therefore, these findings could be used to identify cases that would be benefited from radiotherapy and chemotherapy without surgery. Additionally, this evidence may facilitate the process of treatment planning for the preservation of fertility or ovarian function. In patients in whom lymph node metastasis is detected after radical trachelectomy or ovarian-sparing hysterectomy, concurrent chemoradiotherapy is mandatory, and efforts for the preservation of fertility or ovarian function must be abandoned. Hence, radical surgery instead of conservative surgery would be recommended for patients with an unclear tumor border.
Vimentin is a major constituent of the intermediate filament family. It is mainly expressed in mesenchymal cells, and play critical roles in cell adhesion, migration, and signaling15. In cancer, vimentin is used as a marker of EMT. EMT is a critical process for cancer metastasis16. It has been reported that vimentin is involved in various types of cancer. In prostate cancer, vimentin expression was mainly detected in poorly differentiated tumors and metastatic lesions17. In hepatocellular carcinoma, expression of vimentin was mainly associated with metastasis18. In non-small-cell lung cancer, vimentin overexpression was identified as an independent prognostic indicator19. In cervical cancer, Gilles et al. reported a clear association between vimentin expression and metastatic progression. This conclusion was based on the detection of vimentin in all invasive carcinomas and lymph node metastases, but not in cervical intraepithelial neoplasia 3 (CIN3) lesions20. Moreover, Lin et al. reported that vimentin expression is considered as an independent prognostic factor in cervical cancer7. Collectively, the currently available data suggests that cervical cancers with unclear tumor borders are associated with higher vimentin expression, lymph node metastasis rate, incidence of LVSI, and recurrence rate versus tumors with clear borders. The potential implication of this study is that cervical cancer with unclear tumor border have a high expression of vimentin and enhanced EMT characteristics such as metastatic potential and invasiveness, and therefore have a high risk of upstaging and lymph node metastasis, and of recurrence and poor prognosis.
There are several limitations in the present study. Firstly, the number of patients with identifiable lesions by MRI who underwent operation was small; therefore, further investigation is warranted to validate the present data. Secondly, due to differences in the prognoses of squamous cell carcinoma and adenocarcinoma, this study focused only on the former type of cancer21. Hence, the present findings may not be generalizable to all cervical cancers. Finally, further investigation is warranted to elucidate the mechanism underlying the relationship between vimentin expression and unclear tumor borders.