Micrometastases detected by cytokeratin 19 expression in sentinel lymph nodes of patients with early-stage cervical cancer

The purpose of this study was to detect micrometastases in sentinel lymph nodes (SLNs) by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) analyses for cytokeratin 19 (CK19) expression in early-stage cervical cancer. One hundred twenty-five SLNs were collected from 46 patients with early-stage cervical cancer. Conventional histopathologic techniques revealed 14 metastatic SLNs from 11 out of 46 patients. CK19 expression was detected by RT-PCR and IHC in all the 125 SLNs. Cervical cancer tissues from nine patients and five pelvic lymph nodes from the patients without tumor were utilized as positive and negative controls, respectively. All the metastastic SLNs on conventional histopathologic techniques were positive by either RT-PCR or IHC analyses, while all the positive controls were positive and all the negative controls were negative as expected. Of 35 patients without metastatic SLNs on conventional histopathologic techniques, the detection rate of micrometastases was 42.85% by RT-PCR and 20% by IHC analyses. RT-PCR and IHC were more sensitive to identify micrometastases in SLNs of patients with early-stage cervical cancer than routine pathology. These findings demonstrated that micrometastasis could be identified by molecular technique such as RT-PCR and IHC analyses for CK19 expression. RT-PCR was more sensitive to detect micrometastases in SLNs than IHC in patients with early-stage cervical cancer. Therefore, molecular assessment of the SLNs may be a valuable tool to complement routine histologic examination of cervical cancer. The importance of micrometastases in SLNs is under close clinical observation to determine whether it can be used as a predicting factor to help us make decision whether to proceed with whole-pelvic lymph node dissection or as a prognostic factor for clinical outcome.