Comparison of four tumor markers at the RNA and protein level for the detection of micrometastases and disseminated tumor cells in lymph nodes of patients with cervical carcinoma
Lymph node status is the key prognostic factor for disease recurrence and patient mortality among cervical cancer patients. Patients with positive lymph nodes (pN1) have a high risk for recurrence. However, 15% of treated patients suffer recurrent disease although their lymph nodes have no evident metastases or micrometastases (pN0). The presence of occult tumor cells or tumor cell clusters smaller than micrometastases (<0.2mm) in lymph nodes could be the reason for poor prognosis of these patients. The goal of this dissertation is the detection of occult tumor cells and clusters in lymph nodes by using different molecular tumor markers and the measurement of the reliability on each marker by comparing them to each other. A highly sensitive, and at the same time, specific detection of these tumor cells is a prerequisite for further research confirming the clinical importance of occult tumor cells in lymph nodes. In this study, immunohistochemical staining (IHC) and reverse transcription nested PCR (RT-PCR) were used to detect metastatic tumor cells or clusters in sentinel lymph nodes (SLN) of 48 patients with primary cervical cancer. 120 lymph nodes were evaluated. IHC was performed with a pan-reactive antibody against cytokeratins (AE1/3), an antibody against CK19 and an antibody against p16INK4a. The latter protein, which is a surrogate marker of viral oncogene activity, is invariably upregulated in cervical cancers. Moreover, the viral oncogene (HPV-mRNA) activity was directly detected by RT-PCR.