The prognostic relevance of disseminated nodal tumor cells has been demonstrated by several groups. However, their biological behaviour still remains unclear.
<bold>The aim of the study.</bold> Analyse the phenotypic characteristics of disseminated tumor cells in lymph nodes.
<bold>Material and methods.</bold> We established an immuno-enzymatic immuno-gold double-staining technique to simultaneously identify an epithelial antigen as well as the co-expression of plakoglobin, HLA class-I, ICAM-I and Ki-67 on isolated tumor cells. Epithelial cells were marked by the monoclonal antibody Ber-EP4. These results were compared with the corresponding primary tumors.
<bold>Results.</bold> Loss of HLA class-I expression on Ber-EP4+ cells was observed in 33.3% of the patients. ICAM-I neo-expression was detected in 46%, whereas 54% of the cases were ICAM-1 negative. Plakoglobin was expressed in 16% while Ki-67 was detectable only in 5% of the patients. Comparison with the corresponding primary tumors revealed phenotypic alterations of the disseminated cells. In 20% of the cases HLA class-I down-regulation was found, while in 38% plakoglobin was not detectable. In contrast to the primary tumors with a proliferation index of 39%, the nodal Ber-EP4+ cells appeared to be Ki-67 negative in 95% of the patients.
<bold>Conclusions.</bold> Our phenotypic analysis demonstrates that Ber-EP4+ cells in lymph nodes not only display characteristics typical of malignant cells but also phenotypic alterations, in comparison with primary tumors. This is indicative of a selective process which might result in adapted metastatic phenotypes.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.