In ovarian cancer the prognostic influence of HER2/neu is not dependent on the CXCR4/SDF-1 signalling pathway

HER2/neu overexpression is a driving force in the carcinogenesis of several human cancers. In breast cancer the prognostic influence of HER2/neu was shown to be at least partly based on increased metastatic potential mediated by the chemokine–chemokine receptor pair SDF-1(CXCL12)/CXCR4. We wanted to evaluate the influence of HER2/neu on ovarian cancer prognosis and to investigate whether compromised survival would correlate with CXCR4 expression and/or SDF-1 abundance. Therefore, we analysed HER2/neu, CXCR4, and SDF-1 in 148 ovarian tumour samples by means of immunohistochemistry on tissue microarrays. Overexpression of HER2/neu was found in 27.6% of ovarian cancer tissues and in 15% of ovarian borderline tumours. In ovarian cancer patients, overexpression of HER2/neu correlated closely with overall survival (univariate hazard ratio (HR) 2.59, P=0.005; multiple corrected HR 1.92, P=0.074). In contrast, CXCR4 expression and SDF-1 abundance had no impact on overall survival, and both parameters were not correlated with HER2/neu expression. As expected, cytoplasmic CXCR4 expression and SDF-1 abundance correlated closely (P<0.0001). Our results confirm a univariate influence of HER2/neu expression on overall survival, which was completely independent of the expression of CXCR4 and the abundance of SDF-1, implying significant differences between the HER2/neu downstream pathways in ovarian cancer compared with breast cancer.

Novel MUC1 splice variants are expressed in cervical carcinoma

OBJECTIVES

The MUC1 antigen can be used to identify epithelial cells from the background of hemopoietic cells. The present investigation describes patterns of overexpression of two novel MUC1 splice variants in human cervical carcinoma cell lines.

METHODS

RT-PCR was carried out to determine MUC1 splice variants in the cervical cancer cell lines C-4 II, C-33A, DoTc 2 4510, C-4 I, SiHa, HT3, Hs 636 T (C4-I), and HeLa.

RESULTS

The novel MUC1 splice variant D was expressed in all cell lines and the novel MUC1 splice variant C was expressed in all cell lines but C-33A. Variants A and B were expressed in all (variant A) and all but one (variant B) cell line. MUC1/REP was expressed in all cell lines and MUC1/SEC was positive in all but two cell lines (C-33 A, DoTc 2 4510). All but one cell line (C-33A) expressed MUC1/X and MUC1/Y, and two cell lines (C-33 A, DoTc 2 4510) did not express MUC1/Z, respectively. MUC1 variants A, D, and REP could be demonstrated consistently among all eight cervical carcinoma cell lines we have examined.

CONCLUSIONS

The present study describes the feasibility of detecting a large number of MUC1 variants, including MUC1 variants C and D which are described for cervical carcinoma cells for the first time. Further studies will examine the presence of MUC1 splice variants' expression in human cervical carcinoma tissue.

Comparison of flow cytometry and RT-PCR for the detection of ovarian cancer cells in peripheral blood

Recently, there has been significant effort in developing techniques designed to detect disseminated tumor cells in the peripheral blood (PB). These techniques include immunocytochemical staining of cytocentrifuge slides, flow cytometry, and RT-PCR. Several authors reported various results concerning the sensitivity of the detection limit when applying these methods. The aim of this study was to assess the value of two methods in the detection of ovarian carcinoma cells in the PB. For tumor cell detection we compared RT-PCR to immunomagnetic enrichment followed by flow cytometric analysis. In a model system, single cell suspensions of ovarian cancer cell lines were mixed with full blood samples from healthy donors in order to determine the sensitivity limit of the two methods and to analyze the reproducibility of each. In a multiparameter flow cytometric analysis, tumor cells were defined as cytokeratin 7/8 positive and CD45 negative. RNA was screened for MUC1 mRNA by RT-PCR. MUC1 mRNA expression turned out not to be a specific marker of disseminated ovarian cancer cells, because a weak expression was also found in samples of healthy persons. Using immunomagnetic enrichment followed by flow cytometry, one carcinoma cell per 1 x 10(6) leukocytes was detectable. However, a minimum of 10 ml blood had to be analyzed in order to clearly distinguish real positive tumor cells from false-positive signals.

Expression of mucins and cytokeratins in ovarian cancer cell lines

The expression pattern of the epithelial cell markers MUC1 (CA15-3, EMA), CA125 (OC125), human epithelial antigen HEA (Ber-EP4) and cytokeratins (Ck7, Ck8, Ck7/8, Ck8/18/19) was studied in seven human ovarian cancer cell lines. We analyzed the cell lines by immunofluorescence to determine the surface as well as cytoplasmic expression. Furthermore, we evaluated the mRNA expression of MUC1, Ck18 and Ck19 by reverse transcriptase-polymerase chain reaction (RT-PCR). All cell lines were positive for MUC1. However, expression patterns and staining intensity depended on the different epitope-specific antibodies. CA125, a typical serum marker for ovarian carcinomas, was positive only in two cell lines. HEA was strongly positive in three cell lines, whereas the others expressed the antigen only weakly in the cytoplasm. Ck7 was not expressed in three of the seven cell lines. Ck7/8 was detectable in all cell lines and was strongly expressed in four of them. MUC1 mRNA was expressed by all cell lines as detected by RT-PCR. These findings permit selection of a suitable marker for the detection of disseminated ovarian cancer cells.