Abstract P2-02-15: Elevated serum RAS p21 is an independent prognostic factor in metastatic breast cancer

Background

An important component of the RAS signalling pathway, the RAS p21 oncogene, is frequently hyperactivated in breast cancer. Its expression in tumor tissue has been linked to poor clinical outcome. This study was designed to evaluate the clinical relevance of RAS p21 levels in peripheral blood in a large cohort of metastatic breast cancer patients.

Methods

251 patients with metastatic breast cancer were enrolled in this prospective, multicentre, non-randomized study conducted on behalf of the DETECT Study Group (Current Controlled Trials ISRCTN59722891). Blood samples were collected before start of first-line or later-line treatment. RAS p21 was determined using a sandwich-type ELISA immunoassay. For the determination of the cutoff, blood samples from age-matched healthy controls were analyzed. A value above 452 pg/ml was regarded as elevated (mean + 2 x SD). In the univariate survival analysis, two other cutoffs were considered as well (50th and 75th percentile of patients, i.e. 229 pg/ml and 320 pg/ml). Circulating tumor cells (CTCs) were detected using the CellSearch system.

Results

29 of 251 (12%) patients had RAS p21 levels above the cut-off level of 452 pg/ml. Clinical-pathological parameters, such as hormone receptor and HER2 status, line of therapy and CTC status, did not correlate with RAS p21 levels.

Patients' characteristics. TotalRAS p21 elevated n (%)p-valueOverall25129 (12%) ER status  0.611Negative7610 (13%) Positive17419 (11%) PR status  0.358Negative10114 (14%) Positive14915 (10%) HER2 status  0.873Negative14318 (13%) Positive769 (12%) Metastatic site  0.482Visceral9813 (13%) Bone352 (6%) Both11814 (12%) Extent of metastatic disease  0.768One site849 (11%) Multiple sites16720 (12%) Therapeutic setting  0.2491st-line988 (8%) 2nd-line6611 (17%) 3rd-line or more8610 (12%) Grading  0.604G151 (20%) G212913 (10%) G310314 (14%) Circulating tumor cells  0.101< 5 CTCs / 7.5 ml12217 (14%) ≥ 5 CTCs / 7.5 ml1219 (7%) 

Elevated RAS p21 was significantly associated with shorter progression-free and overall survival in the univariate analysis (median PFS: 3.9 months [95%-CI: 1.8-6.0] for patients with elevated RAS p21 levels versus 8.5 months [95%-CI: 7.4-9.5] with non-elevated levels [p = 0.01]; median OS: 7.1 months [95%-CI: 0.3-14.2] versus not reached [p = 0.002], respectively). When RAS p21 cutoffs other than 452 pg/ml were considered, elevated RAS p21 was significantly associated with OS (p = 0.019 in case of 229 pg/ml; p = 0.003 in case of 320 pg/ml), but not with PFS. Classical clinical-pathological factors were included into a multivariate Cox regression analysis. In addition, factors previously shown to influence survival in a univariate analysis, such as serum HER2, CAIX and TIMP1, were included as well. In the multivariate analysis, RAS p21, presence of ≥ 5 CTCs per 7.5 ml blood, higher grading and higher line of therapy remained independent predictors of shorter OS.

Conclusions

This is the first study to address the clinical relevance of circulating RAS p21 in a large group of metastatic breast cancer patients. Patients with elevated levels of circulating RAS p21 had significantly worse clinical outcome. Hypothetically, these patients might benefit from therapeutic strategies targeting RAS pathway.

Citation Format: Banys-Paluchowski M, Fehm T, Janni W, Aktas B, Fasching PA, Kasimir-Bauer S, Milde-Langosch K, Pantel K, Rack B, Riethdorf S, Solomayer E-F, Witzel I, Müller V. Elevated serum RAS p21 is an independent prognostic factor in metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-15.

Abstract P6-17-06: Relevance of the hyaluronidase-1 (HYAL1) in brain metastasis formation of breast cancer patients

The incidence of brain metastases in breast cancer (BMBC) patients has increased in the last years and represents the major life-limiting problem for metastatic breast cancer (BC) patients. However, the knowledge about tumor cell invasion in the brain is still very limited and new markers for brain metastasis incidence are urgently needed in order to early detect high risk patients.

In a recent study based on cDNA microarray data of primary breast tumors, we could show that mRNA expression of certain glycosylation enzymes significantly correlates with an organ-specific metastatic spread. Interestingly, hyaluronan synthase 2 (HAS2) and hyaluronidase-1 (HYAL1), both genes involved in hyaluronan (HA) metabolism, showed an independent prognostic value and a significant correlation with brain metastasis formation.

In order to corroborate the role of these enzymes at protein level, we examined the expression of HYAL1 and HAS2 on a tissue microarray including 200 primary BC samples. Here, the prognostic impact of HAS2 could not be validated, whereas for HYAL1 shorter disease free survival (DFS) was observed for patients with high HYAL1-expression levels. This trend could be additionally verified in a second cohort of 107 BC samples, using western blot analysis. Moreover, significantly higher HYAL1 expression was detected among primary tumors with subsequent brain metastases compared with those without brain metastases using immunohistochemistry (IHC).

No impact of HYAL1 expression on disease progression of BCBM patients could be observed after analysis of 87 brain metastasis samples. Here, quantification of tumor-associated HA revealed a significant positive correlation with triple negative tumors and a trend towards shorter progression-free survival.

Taken together, our data suggest a role of the enzyme HYAL1 for progression and especially for the development of brain metastases in breast cancer patients.

Citation Format: Oliveira-Ferrer L, Anna M, Wickman H, Matschke J, Schumacher U, Milde-Langosch K, Müller V, Witzel I. Relevance of the hyaluronidase-1 (HYAL1) in brain metastasis formation of breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-17-06.

Prognostic impact of transcription factor Fra-1 in ER-positive breast cancer: contribution to a metastatic phenotype through modulation of tumor cell adhesive properties

PURPOSE

The transcription factor Fos-related antigen-1 (Fra-1) has been described to affect the morphology, motility and invasive potential of breast cancer cells. Since tumor cell adhesion plays an essential role in the metastatic process, especially for extravasation from blood vessels, we investigated the influence of Fra-1 on breast cancer cell interactions with the endothelium.

METHODS

Using Fra-1-overexpressing MCF7 [weakly invasive, estrogen receptor (ER)-positive] and MDA MB231 (strongly invasive, ER-negative) cells, we performed dynamic cell flow adhesion assays on surfaces coated with E-selectin or with human pulmonary microvascular endothelial cells.

RESULTS

We found a significant increased adhesion of Fra-1-overexpressing MCF7 cells to E-selectin but also to activate endothelial cells, whereas the MDA MB231 cell line showed moderate enhanced cell rolling and tethering on both coated surfaces. These different adhesion behaviors corresponded to an up-regulation of various adhesion-related proteins such as CD44 and integrin α5 in Fra-1-overexpressing MCF7 cells measured by microarray analysis and flow cytometry in comparison with no deregulation of key adhesion molecules observed in Fra-1-overexpressing MDA MB231 cells. In line with these results and based on cDNA microarray data of breast cancer patients (n = 197), high Fra-1 expression significantly correlates with shorter overall survival and higher rate of lung metastasis in ER-positive breast cancer patients (n = 130), but has no impact on the prognosis of patients with ER-negative tumors.

CONCLUSION

Thus, in addition to its pro-invasive and pro-migratory effect, Fra-1 might influence the metastatic potential of breast cancer cells by changing the expression of adhesion molecules, resulting in increased adherence to endothelial cells under flow conditions.

c-FOS suppresses ovarian cancer progression by changing adhesion

Background:

C-Fos was initially described as oncogene, but was associated with favourable prognosis in ovarian cancer (OvCa) patients. The molecular and functional aspects underlying this effect are still unknown.

Methods:

Using stable transfectants of SKOV3 and OVCAR8 cells, proliferation, migration, invasion and apoptotic potential of c-FOS-overexpressing clones and controls were compared. Adherence to components of the extracellular matrix was analysed in static assays, and adhesion to E-selectin, endothelial and mesothelial cells in dynamic flow assays. The effect of c-FOS in vivo was studied after intraperitoneal injection of SKOV3 clones into SCID mice, and changes in gene expression were determined by microarray analysis.

Results:

Tumour growth after injection into SCID mice was strongly delayed by c-FOS overexpression, with reduction of lung metastases and circulating tumour cells. In vitro, c-FOS had only weak influence on proliferation and migration, but was strongly pro-apoptotic. Adhesion to components of the extracellular matrix (collagen I, IV) and to E-selectin, endothelial and mesothelial cells was significantly reduced in c-FOS-overexpressing OvCa cells. This corresponds to deregulation of adhesion proteins and glycosylation enzymes in microarray analysis.

Conclusion:

In addition to its known pro-apoptotic effect, c-FOS might influence OvCa progression by changing the adhesion of OvCa cells to peritoneal surfaces.

P2-01-17: L1-CAM Promotes Adhesion of Breast Cancer Cells to the Endothelium

Background: Overexpression of the adhesion molecule L1 -CAM (L1) in breast cancer is correlated with nodal involvement, high grading, and a shorter recurrence-free and overall survival, but the mechanism leading to this effect is poorly understood. L1 is also expressed in endothelial cells promoting the interaction between lymphatic cells and endothelia via homophilic L1-L1 interaction. This mechanism might also mediate adhesion of breast cancer cells to endothelia and thus promote metastasis. To examine this likely role of L1, the impact of L1 expression in breast cancer cells on their adherence to human pulmonary microvascular endothelial cells (HPMEC) was investigated and potential L1 ligands on these cells were identified. Methods: MDA-MB231-Fra2 breast cancer cells expressing high levels of L1 were stably transfected with shRNA vectors to generate two clones with strong L1 downregulation (L1low clones). Adherence of these clones to endothelial cells was studied in dynamic cell-flow adhesion assays in channels seeded with HPMEC simulating in vivo-conditions. Rolling or adherent cells per minute were counted using CapImage software. For the cell-flow assay HPMEC were activated with TNFα. In order to identify the L1 ligand, endothelial cells were partly pre-incubated with blocking antibodies directed to the potential binding partners L1, ALCAM, ICAM-1 and E-selectin before interaction with tumor cells. In additional experiments, flow chambers were coated with recombinant L1-CAM, ICAM1, ALCAM or E-selectin, and the adherence of MDA-MB231 cells with high or low L1 expression to these proteins was investigated.

Results: Adhesion of MDA-MB231 cells to activated HPMEC was significantly higher in L1high cells compared to L1low clones, where the number of adherent cells was only 40–50% of the L1high control (p=0.025; p=0.035). Blocking experiments showed that the adherence of L1high cells could be reduced by antibodies directed to ALCAM (p=0.0007), but not to ICAM1. Anti-L1 antibodies had a significant effect only in passages of endothelial cells which showed L1 expression, whereas E-selectin blocking strongly diminished adherence of breast cancer cells irrespective of their L1 expression. In addition, L1low clones showed significantly lower adhesion to recombinant L1, ALCAM and E-selectin proteins compared to the parental cells.

Conclusion: Our experiments indicate that L1 expression in breast cancer cells leads to an increased adherence to activated endothelial cells via homophilic (L1-L1) or heterophilic (L1-ALCAM) interactions. This mechanism is a possible explanation for the increased metastatic potential and poor prognosis in L1-positive carcinomas observed in vivo. Our results suggest that this adhesion molecule might be a suitable target for therapeutic interventions.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-01-17.

Combination of osteopontin and activated leukocyte cell adhesion molecule as potent prognostic discriminators in HER2- and ER-negative breast cancer

BACKGROUND

To analyse the discriminative impact of osteopontin (OPN) and activated leukocyte cell adhesion molecule (ALCAM), combined with human epidermal growth factor 2 (HER2) and oestrogen receptor (ER) in breast cancer.

METHODS

Osteopontin, ALCAM, HER2 and ER mRNA expression in breast cancer tissues of 481 patients were analysed (mRNA microarray analysis, kinetic RT-PCR). Hierarchical clustering was performed in training cohort A (N=100, adjuvant treatment) and validation cohorts B (N=200, no adjuvant treatment, low-risk) and C (N=181, adjuvant treatment, high-risk).

RESULTS

Negative/low ER and HER2, high OPN and low ALCAM mRNA expression helped to identify patients at particularly high risk, showing shorter DFS, P<0.001, and OAS, P=0.001. Although both validation cohorts showed diverse risk and treatment profiles, this marker constellation was concordantly associated with shorter DFS and OAS (P<0.001 and P=0.075 for cohort B and P=0.043 and P<0.001 for cohort C, respectively). In multivariate analysis, this algorithm was the main independent prognostic factor. Cohort B: DFS, P=0.0065, OAS, not significant; cohort C: DFS, P=0.026, OAS, P<0.001.

CONCLUSION

Activated leukocyte cell adhesion molecule and OPN mRNA expression has a strong discriminative impact on survival within cancer patients with low or negative expression of ER and HER2, so called 'high-risk' breast cancers, and might help in identifying patients who could benefit from new treatment approaches like targeted therapies in the adjuvant setting.

Expression levels of Activated Leukocyte Cell Adhesion Molecule (ALCAM/CD166) in primary breast carcinoma and distant breast cancer metastases

Introduction: Activated Leukocyte Cell Adhesion Molecule (ALCAM/CD166) gained increasing attention regarding tumorprogression and metastatic spread in breast cancer. The aim of this study was to examine ALCAM expression levels in primary breast cancer and distant metastases of the same patient within 29 autopsy cases to better understand the underlying mechanisms of metastases and the role of adhesion molecules in this process.

Material and Methods: Paraffin-embedded tissue of the primary and distant metastases (N = 84) were collected and ALCAM immunohistochemistry was performed.

Results: The primary tumor and all metastases showed a statistically normally distributed ALCAM expression. ALCAM expression level average differs between immunoreactive score (IRS) (mean) 4.16 (lung)-5.00 (adrenal gland). Of the metastatic ALCAM expression levels we obtained an intra-class correlation (ICC) of 80.9%, indicating a strong cluster effect of measurements in the same patient. ALCAM expression scores in metastatic sites and in the primary analyzed by hierarchical regression analysis showed that ALCAM expression in the primary is prognostic for ALCAM expression in all different sites of metastases (slope = 0.773, p < 0.001, r² = 0.504).

Conclusion: ALCAM expression in the primary is positively correlated to ALCAM expression in metastases within one single patient. This could show a tumorbiological context of ALCAM for the development of metastases in breast cancer.

Comparison of Prognostic Signatures in Node-Negative Tamoxifen-Treated Breast Cancer Patients

Background: A number of molecular signatures have been published to aid breast cancer prognosis and therapy response prediction. A 76-gene signature has been developed in a node-negative patient cohort that did not receive systemic therapy.1 Another prognostic 97-gene signature measures predominantly proliferation-associated genes.2 Finally, a 21-gene signature has been developed for node-negative and estrogen receptor–positive breast cancer patients treated with tamoxifen in the adjuvant setting.3 Here we compare the prognostic performance of all three published algorithms in a cohort of 189 node-negative breast cancer patients treated with tamoxifen.Materials and Methods: Fresh-frozen tumors from node-negative patients were profiled on HG-U133a arrays. In addition, HG-U133a datasets with clinical annotation were downloaded from GEO (http://www.ncbi.nlm.nih.gov/geo/). All patients received tamoxifen only as adjuvant treatment after surgery. We determined the molecular subclass on the basis of ESR1 and ERBB2 mRNA expression; only ESR1-positive and ERBB2-negative tumors were considered for further analysis, leaving 141 in-house and 48 public datasets. After mapping of the gene signatures to the HG-U133a platform, we performed Cox regression and ROC curve analysis with distant metastasis as endpoint.Results: Cox regression analysis yielded a significant outcome association for all three gene signatures (76-gene signature: P = 0.0018; 97-gene signature: P = 0.0294; 21-gene signature: P = 0.0025) in the whole ESR1+/ERBB2– cohort. However, the 97-gene signature did not yield a significant result by ROC analysis for distant metastasis at 5 years (76-gene signature: AUC = 0.645, CI = 0.505–0.785; 97-gene signature: AUC = 0.608, CI = 0.462–0.754; 21-gene signature: AUC = 0.744, CI = 0.633–0.854). In addition, when the analysis was restricted to grade 2 tumors (n = 114), only the 21-gene signature remained prognostic by Cox regression (76-gene signature: P = 0.2405; 97-gene signature: P = 0.9001; 21-gene signature: P = 0.047) as well as by ROC curve analysis at 5 years (76-gene signature: AUC = 0.575, CI = 0.398–0.751; 97-gene signature: AUC = 0.532, CI = 0.347–0.717; 21-gene signature: AUC = 0.699, CI = 0.549–0.849).Discussion: While all three gene signatures reveal a significant outcome association in our whole patient cohort by Cox regression analysis, only the 21-gene signature remains significant in a subset analysis of grade 2 tumors. Since this group is clinically particularly challenging, further comparison between prognostic gene signatures in homogeneously treated patient cohorts is needed.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 104.

[Expression of activated leukocyte cell adhesion molecule in breast cancer. Predictability of the response to taxane-free chemotherapy]

AIMS

Activated leukocyte cell adhesion molecule (ALCAM) is a cell surface immunoglobulin expressed in breast cancer (BC) and is assumed to be implicated in tumourigenesis and tumour progression. The importance of the adhesion molecule ALCAM for the response to taxane-free adjuvant chemotherapy was investigated.

MATERIALS AND METHODS

Tissue specimens from 162 primary breast cancer patients were analyzed. Immunohistochemical staining (IHC) and Western blots (WB) were performed using monoclonal antibody against ALCAM. Relative protein amounts in WB bands were determined densitometrically. ALCAM mRNA expression was evaluated by microarray analysis (Affymetrix).

RESULTS

In the normal breast ALCAM is expressed in luminal and basal epithelial cells. In BC samples, WB analysis showed a significant positive correlation of ALCAM levels with estrogen receptor status (p=0.04). For patients who received a taxane-free chemotherapy, a high ALCAM expression was predictive for a good response to chemotherapy. Median mRNA expression of ALCAM was 4.5-fold higher in patients alive at the time of follow-up compared to those who died of breast cancer.

CONCLUSIONS

Higher ALCAM expression showed a positive correlation with estrogen receptor status and is a useful predictive marker for the response to taxane-free chemotherapy.

Upregulation of Fra-1 and Fra-2 in breast cancer cells results in changes in adhesion, migration, invasion and stem cell markers

Abstract #2058

Background: Fra-1 and Fra-2 (Fos-related antigen1 and 2) are members of the Fos family of AP-1 transcription factors which are often up-regulated in human mammary carcinomas. The results of previous studies with clinical tumor tissues and experimental studies of breast cancer cell-lines suggested that they might be involved in the regulation of tumor invasion and metastasis in breast cancer.&#x2028; Materials and Methods: In order to analyze the impact of Fra-1 and Fra-2 on the aggressive behavior of breast cancer cells, we established stable transfectants of the weakly invasive MCF-7 cells and as well in the highly invasive MDA-MB231 breast cancer cells with Fra-1 and Fra-2 overexpression. Additionally we generated MCF-7 stable transfectants with inducible Fra-2 transcription controlled by the tetracycline-inducible tetON-system. The consequences of Fra-1 and Fra-2 upregulation on the biology of the breast cancer cells were analysed by MTT assays (proliferation) and Matrigel invasion assays (invasion and motility). In addition, possible target genes which were differentially regulated in stable transfectants with Fra-1 and Fra-2 overexpression were identified by microarray analysis and, partly Western blots.&#x2028; Results: Cell proliferation was not influenced by Fra-1 and Fra-2. In contrast, the invasive potential of the cells was increased by Fra-1 and Fra-2 in MDA-MB231 and MCF7 cells. In addition, there was a similar effect on cell motility. By using the GeneChip Human Genome U133A 2.0 array (Affymetrix), we identified several genes which are known to be involved in cell adhesion, migration or invasion and which were up- or downregulated in stable transfectants, i.e. ICAM, L1CAM, ALCAM, CX43 etc. Moreover, Fra-2 overexpression in MDA-MB231 cells resulted in CD44 upregulation and CD24 downregulation, which is characteristic of breast cancer stem cells.&#x2028; Discussion: In clinical breast cancer tissues, up-regulation of Fra-2 and Fra1 protein expression has been observed and was shown to be associated with a more aggressive phenotype. Our data of the experimental studies with breast cancer cell-lines indicates that Fra-2 as well as Fra-1 may play an important role in tumor progression by transcriptional regulation of genes which are involved in cell adhesion, invasion and motility.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2058.

Prediction of chemotherapy response in breast cancer by using a four-gene panel including osteopontin, activating leukocyte cell adhesion molecule (ALCAM), HER2 and estrogen receptor (ER)

Abstract #2033

Background: Several prognostic factors such as TNM-stage, hormone receptor and HER2 status refer to therapeutical decisions towards adjuvant chemotherapy. Up to now it is still difficult to predict the response to chemotherapy for a single patient, which is a challenging problem in order to spare patients from cost-intensive ineffective treatment and adverse side effects. Therefore there is urgent need for additional predictive markers. Our previous findings implicated that tumor tissue expression of Activated Leucocyte Cell Adhesion Molecule (ALCAM/CD166) is associated with chemotherapy response. Osteopontin (OPN) has been described as prognostic marker in breast cancer and recently it was shown that high OPN levels in vitro mediate chemoresistance of breast cancer cells by inhibition of apoptosis. If these findings result in chemoresistance in vivo has not been investigated so far. Material and Methods: Primary breast cancer tissues from 100 patients treated with Taxane-free adjuvant standard chemotherapy regimen were collected at surgery prior to any additional therapy. The median follow-up time was 81 months. We analyzed ALCAM and OPN mRNA expression in the biological context of additional and predefined breast cancer markers, like estrogen receptor (ER), Her-2/neu (HER2), members of the urokinase plasminogen activator (uPA) system, vascular endothelial growth factor (VEGF) using oligonucleotide microarrays (Affymetrix HG-U133A). Hierarchical cluster analysis was performed to develop a gene algorithm predicting outcome after standard chemotherapy. Results: In contrast to ALCAM overexpression, which was associated with better outcome upon chemotherapy, OPN overexpression was associated with a significantly higher recurrence rate (p=0,027), but not with shorter overall survival. In addition, there were significant positive correlations of OPN with uPA, PAI-1, uPAR and VEGF-A mRNA expression. By cluster analysis based on the four markers ER, HER2, ALCAM and OPN, we identified a group of high-risk patients, which was characterized by low ER and HER2 expression, high OPN and low ALCAM levels, and with significantly shorter recurrence-free and overall survival (p&lt;0,001). Discussion: In our cohort of patients the combination of ALCAM, OPN, ER and HER2 expression levels turned out as valuable predictive marker for response to adjuvant Taxane-free chemotherapy. The ratio of high OPN and low ALCAM levels was particularly associated with chemoresistance and a poor prognosis in tumors having low ER and HER2 expression levels. We hypothesize that this simple four-gene panel could help to reassign an optimized therapy to the single patients.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2033.

Predictive impact of activated leukocyte cell adhesion molecule (ALCAM/CD166) in breast cancer

Activated Leukocyte Cell Adhesion Molecule (ALCAM, also called CD 166, MEMD) as cell surface immunoglobulin is reported as prognostic marker in breast cancer, but its predictive value has not yet been evaluated. We have analyzed ALCAM protein expression by Western Blot analysis (n = 160) and mRNA expression by cDNA microarray analysis (n = 162) in primary mammary carcinomas. Both expression results were obtained in 133 cases, showing a strong positive correlation between protein expression and mRNA expression (P < 0.001). Neither ALCAM protein nor mRNA expression are correlated to histological type, grading, stage or age of patient. However, ALCAM protein expression correlates positively with estrogen receptor status (ER) (P = 0.025). A stratified subgroup analysis showed positive correlation of high ALCAM mRNA expression with longer overall survival (OAS; P = 0.0012) in patients treated with adjuvant chemotherapy (n = 100). In contrast, patients with high ALCAM mRNA expression who did not receive chemotherapy tended to have a worse prognosis. Similar but weaker correlations were found regarding ALCAM protein expression data. The predictive impact of ALCAM mRNA expression in chemotherapy treated patients was corroborated by multivariate Cox regression analysis also including histopathological markers (P = 0.001 for OAS). Our overall results reveal that high ALCAM expression levels in primary tumors might be a suitable marker for prediction of the response to adjuvant chemotherapy in breast cancer.

Expression and prognostic relevance of activated extracellular-regulated kinases (ERK1/2) in breast cancer

Extracellular-regulated kinases (ERK1, ERK2) play important roles in the malignant behaviour of breast cancer cells in vitro. In our present study, 148 clinical breast cancer samples (120 cases with follow-up data) were studied for the expression of ERK1, ERK2 and their phosphorylated forms p-ERK1 and p-ERK2 by immunoblotting, and p-ERK1/2 expression in corresponding paraffin sections was analysed by immunohistochemistry. The results were correlated with established clinical and histological prognostic parameters, follow-up data and expression of seven cell-cycle regulatory proteins as well as MMP1, MMP9, PAI-1 and AP-1 transcription factors, which had been analysed before. High p-ERK1 expression as determined by immunoblots correlated significantly with a low frequency of recurrences and infrequent fatal outcome (P=0.007 and 0.008) and was an independent indicator of long relapse-free and overall survival in multivariate analysis. By immunohistochemistry, strong p-ERK staining in tumour cells was associated with early stages (P=0.020), negative nodal status (P=0.003) and long recurrence-free survival (P=0.017). In contrast, expression of the unphosphorylated kinases ERK1 and ERK2 was not associated with clinical and histological prognostic parameters, except a positive correlation with oestrogen receptor status. Comparison with the expression of formerly analysed cell-cycle- and invasion-associated proteins corroborates our conclusion that activation of ERK1 and ERK2 is not associated with enhanced proliferation and invasion of mammary carcinomas.

Vitamin B6 Modulates Glucocorticoid-Dependent Gene Transcription in a Promoter- and Cell Type-Specific Manner

Due to their immunosuppressive effects, glucocorticoids (GC) are widely used in the treatment of inflammatory and autoimmune states. However, long-term GC treatment is associated with severe side effects. To increase the ratio of wanted and unwanted GC effects, is, therefore, a desirable goal, which could be achieved by either developing new "dissociating" GC or by combining conventional GC therapy with substances that selectively interfere with glucocorticoid receptor (GR) function. Vitamin B6 was previously shown to inhibit GR transactivation in non-immune cells. In the present study, we tested whether vitamin B6 would also interfere with GR function in immune cells and/or with transrepression in non-immune cells. Normal human lymphocytes and Jurkat T lymphoma cells were transfected with luciferase reporter constructs under the control of the interleukin-2 (IL-2) and the leukemia inhibitory factor (LIF) promoter, respectively. Cells were stimulated with phorbol ester, ionomycin, and different concentrations of dexamethasone, either in the absence (a vitamin B6-free medium was especially prepared for this study) or presence of vitamin B6. Both promoters were strongly induced in response to phorbol ester and ionomycin. Dexamethasone inhibited this effect in a dose-dependent manner both in the presence and absence of vitamin B6. Similar results were obtained at the protein level (IL-2- and LIF-specific ELISAs). Induction of a glucocorticoid response element (GRE)-driven promoter construct by dexamethasone in lymphoid cells was only marginally reduced by vitamin B6. In contrast, GR-mediated transactivation was strongly inhibited by vitamin B6 in HeLa cells, while GR-mediated transrepression of a matrix metalloproteinase 9 (MMP9) promoter construct was not affected. Our data indicate that vitamin B6 does not interfere with GC action in immune cells (wanted GC effects) while selectively inhibiting GR-dependent transactivation in non-immune cells (unwanted GC effects). Combination of GC treatment with supraphysiological doses of vitamin B6 may, thus, reduce the side effects of this type of immunosuppressive therapy, provided that the observed effects can be reproduced at subtoxic vitamin B6 concentrations in vivo.

Genomic structure and transcriptional regulation of the human NAD+-dependent 15-hydroxyprostaglandin dehydrogenase gene

The NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase (PGDH) is a catabolic enzyme that controls the biological activities of prostaglandins by converting them into inactive keto-metabolites. Here we report the genomic organisation of the complete human PGDH gene and characterise its transcriptional regulation. The PGDH gene spans about 31 kb on chromosome 4 and contains 7 exons. Within 2.4 kb of the 5'-flanking sequence we identified two regions with clustered putative transcription factor binding sites. The distal promoter element PGDH-DE (positions-2152/-1944 relative to the start codon) contains binding sites for Ets and activating protein-1 (AP-1) flanked by two cAMP-responsive element-binding protein binding sites (CREB1, CREB2), whereas the proximal element PGDH-PE (-235/-153) includes an Ets and an AP-1 binding sequence. By electrophoretic mobility shift assay, no high affinity binding of Ets or AP-1 factors was observed with PGDH-PE, whereas we confirmed interaction of members of the Ets, AP-1 and CREB families of transcription factors with PGDH-DE. Transcriptional control of the PGDH promoter was assessed by transiently transfecting JEG-3 choriocarcinoma cells. A luciferase reporter gene construct containing the PGDH-PE was not induced by c-jun/c-fos in the absence or presence of co-expressed Ets-1. A construct carrying the PGDH-DE in front of the minimal homologous promoter was activated by co-transfection of expression vectors for AP-1 proteins. Mutation of the AP-1 or CREB2 site reduced the response to c-jun/c-fos, whereas mutation of the Ets site of the distal element reduced basal promoter activity. CREB activated the PGDH-DE construct through the CREB1 site. These results defined the distal element as an integrator of transcriptional regulation by AP-1, Ets and CREB proteins.

PTEN expression in breast and endometrial cancer: correlations with steroid hormone receptor status

OBJECTIVE

The PTEN (MMAC1/TEP1) tumor suppressor gene is frequently mutated and homozygously deleted in human neoplasms, but there is only sparse information about PTEN protein expression in hormone-dependent female tumors. Therefore, we investigated PTEN expression in 68 breast and 43 endometrial carcinomas.

METHODS

For PTEN protein detection, we used Western blot analysis followed by densitometry and compared these data with clinicopathologic parameters, the estrogen receptor (ER) and progesterone receptor (PR) status, HER2/neu and the proliferation marker Ki67.

RESULTS

We were able to show significantly decreased PTEN protein expression in endometrial carcinomas compared with normal endometrial tissue samples, especially in the endometrioid histological subtype. In contrast, PTEN downregulation was found more rarely in breast cancer. Lower PTEN expression in breast cancer correlated significantly with high ER immunoreactivity (p = 0.008) and was weakly associated with PR expression (p = 0.055) and low histological grading (p = 0.081). No correlation with any of these parameters was observed in endometrial tumors. In both tumor types, no association of PTEN expression with any other analyzed parameter was found.

CONCLUSIONS

These results suggest that PTEN expression plays different roles in the pathogenesis of endometrial carcinomas and breast cancer. In mammary carcinomas, loss of PTEN expression is mainly found in more differentiated tumors and is probably not a major event in carcinogenesis.

Overexpression of the p16 cell cycle inhibitor in breast cancer is associated with a more malignant phenotype

In order to study the role of the p16INK4A(MTS1/CDKN2a) tumor suppressor in breast cancer, we analyzed p16 protein expression in 60 breast cancer samples which were also analyzed for expression of Rb, Ki67, HER2/neu, and estrogen and progesterone receptors (ER, PR). P16 expression was investigated by two methods: western blotting (WB) followed by densitometry, and immunohistochemistry (IHC). The Rb status was studied by western blotting, and expression of Ki67, HER2/neu, ER, and PR was analyzed immunohistochemically. P16-negative results were found in 18% of the carcinomas by WB, but in only one case by IHC and were not associated with established prognostic parameters. In contrast, p16 overexpression which was detected by WB and IHC in 15% and 25% of the tumors, respectively, was significantly associated with unfavorable prognostic indicators. High p16 expression as detected by both methods correlated significantly with high grading and a negative estrogen receptor status. In addition, a significant association of p16 staining with inverse progesterone receptor status and high Ki67 expression was found with IHC. No correlation of p16 expression with clinical stage, HER2/neu immunostaining, Rb expression or Rb phosphorylation was found. Comparison of western blot results and immunohistochemistry suggests that both nuclear and cytoplasmic immunoreactivity in tumor cells is specific and due to p16 expression. We conclude that high p16 reactivity (both nuclear andcytoplasmic) is indicative of a more undifferentiated, malignant phenotype in mammary carcinomas.

Frequent p16/MTS1 inactivation in early stages of urothelial carcinoma of the bladder is not associated with tumor recurrence

OBJECTIVE

p16, located at chromosome 9p21, is a negative regulator of G1 cell checkpoint and functions as tumor suppressor gene. Only few data are available on the frequency and clinical relevance of p16 alterations in Ta, T1 transitional cell carcinoma (TCC) of the bladder. We investigated 40 patients with Ta, T1 TCC of the bladder for p16 alterations (mutations, homozygote deletions, allelic loss) or reduced p16 immunoreaction.

PATIENTS AND METHODS

DNA was prepared from microdissected tumor tissue from 40 patients with pTa, pT1 TCC of the bladder (pTa: 18 patients; pT1: 22 patients; grade 1: 7 patients; grade 2: 28 patients; grade 3: 5 patients). Mutation screening was performed using polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP) and direct sequencing at exon 1 and exon 2. Detection of homozygote deletions was performed using multiplex PCR. Immunohistochemistry (IHC) was performed using an anti-human monoclonal antibody (p16, Pharmingen). Allelic loss was detected by PCR using three different microsatellite markers (D9S161, D9S171, D9S319).

RESULTS

SSCP and direct sequencing revealed 3 cases of base substitution which turned out to be natural polymorphisms. Homozygote deletions were not detected in any case. p16 IHC revealed reduced p16 expression (<5% positive nuclei) in 10 patients; 30 patients had a positive reaction (> or =5% positive nuclei) and 10 patients a strong positive reaction (> or =50% positive nuclei). Thirteen of 37 informative cases revealed loss of heterozygosity (LOH) with at least one marker. After a median follow-up of 23 months, 15 patients suffered from disease recurrence. Statistical analysis using Kaplan-Meier analysis and the log-rank test did not reveal significant association of recurrence-free interval and detection of LOH (p = 0.34) or p16 IHC (p = 0.9).

CONCLUSIONS

We present a comprehensive evaluation of chromosome 9p21 alterations including p16 analysis and clinical follow-up data. Although p16 mutations and homozygote deletions are rarely detectable in Ta, T1 TCC, the reduction of p16 expression and the frequent hemizygote deletions at 9p21 suggest an early involvement of chromosome 9p and p16 in superficial TCC.

The glucocorticoid receptor is specifically expressed in the stromal compartment of the human endometrium

The human endometrium is a classical target tissue for steroid hormones. While the expression pattern and functional roles of both the estrogen receptor (ER) and the progesterone receptor (PR) are well defined, expression of the glucocorticoid receptor (GR) in this tissue has not been described so far. In the present study, we used immunohistochemistry to analyze the expression of GR in the normal human endometrium throughout the menstrual cycle. The expression of GR was compared to that of ER and PR, which were analyzed in parallel. We show that GR is expressed in the human endometrium with a pattern that markedly differs from the expression patterns of ER and PR. ER and PR are expressed in the nuclei of endometrial glands, whereas GR is completely absent from these structures. However, GR is strongly expressed in the stromal compartment of the endometrium throughout the cycle. Both stromal fibroblasts and lymphocytes are GR-positive. In addition GR expression is also observed in the endothelium of small endometrial blood vessels, which are ER- and PR-negative. Western blot analysis performed on endometrial tumor cell lines of glandular (HEC-1B) and mesodermal (SKUT-1B) origin, respectively, showed GR expression only in the latter. In summary, we demonstrate that GR is expressed in fibroblasts, lymphocytes and endothelial cells of the human endometrial stroma, while it is absent from the glandular compartment. The specific expression pattern of GR within the human endometrium points to a possible functional role of glucocorticoids in the process of decidualization which occurs primarily in the stromal compartment.

Expression pattern of the AP-1 family in endometrial cancer: correlations with cell cycle regulators

PURPOSE

To study the expression pattern and the role of the AP-1 (activating protein-1) family of transcription factors in endometrial carcinogenesis.

METHODS

We performed Western blot experiments with specific antibodies for each of the AP-1 proteins (c-jun, junB, junD, c-fos, fosB, fra-1, fra-2) with 41 endometrial carcinomas. Expression levels of the AP-1 factors were correlated with clinico-pathologic tumor parameters, steroid receptor status, Ki-67 expression and the expression levels of eight cell cycle regulatory proteins (cyclin D1, cyclin E, cyclin B1, cdk2, cdk4, p16, p21, and Rb).

RESULTS

Of the seven AP-1 factors, three (c-fos, fra2, and junB) clearly showed higher expression levels in tumors when compared to matched normal endometrial samples. These factors also correlated significantly with cell cycle promoters (c-fos with cyclin E, cyclin B1, cdk2, and cdk4; fra-2 with cyclin B1; and junB with cyclin D1). Furthermore, high c-fos expression correlated with low ER and PR immunoreactivity and high grading (G3). On the other hand, correlations with classic cell cycle inhibitors (Rb, p16, p21) have also been observed for all AP-1 factors except c-jun and junD.

CONCLUSIONS

Our results indicate that the AP-1 family of transcription factors is probably implicated in the regulation of cell cycle progression and control in endometrial carcinomas. In particular, c-fos might be an additional negative prognostic factor and/or implicated in tumor progression in endometrial cancer.

Expression of cell-cycle regulatory proteins in endometrial carcinomas: correlations with hormone receptor status and clinicopathologic parameters

PURPOSE

The normal human endometrium is characterized by hormone-dependent variations in the levels of cell-cycle regulatory proteins during the menstrual cycle. As this tightly controlled system is disturbed in endometrial carcinomas, we analyzed which cell-cycle regulators are involved in endometrial carcinogenesis.

METHODS

We performed Western blot analysis of five cell-cycle stimulating (cyclins D1, E, B1, cdk2, cdk4) and three cell-cycle inhibiting (p16(INK4a), p21(WAF1), Rb) proteins in 41 endometrial carcinoma specimens. In addition, expression of the estrogen and progesterone receptors (ER, PR), Ki67, and, in selected cases, p16, cyclin E, and cyclin B1 was studied by immunohistochemistry.

RESULTS

We found upregulation of all analyzed cell-cycle regulators in most tumors compared to normal endometrial tissue samples. Overexpression of cyclin E, cyclin B1, and p21 was associated with a less differentiated phenotype. In addition, high levels of cyclin E, cdk2, and cdk4 correlated with weak/absent ER expression, and p16 and p21 overexpression was significantly associated with low PR immunoreactivity. Cyclin B1 expression correlated with cyclin E, cdk2, cdk4, p21, Rb, and Ki67, and cyclin E expression with cyclin D1 and Rb.

CONCLUSIONS

We conclude that cyclin E and cyclin B1 might be the major cell-cycle regulators involved in proliferation and reduced differentiation of endometrial carcinomas. In addition, p16, p21, and Rb appear to be uncoupled from their normal cell-cycle inhibiting function in many endometrial carcinomas.

Expression of Rb2/p130 in breast and endometrial cancer: correlations with hormone receptor status

Rb2/p130 is a member of the retinoblastoma family of proteins, consisting of Rb, Rb2 and p107, which are important negative regulators of cell cycle progression and differentiation. While Rb2 downregulation was observed in several malignant tumours including endometrial cancer, the role of p130 in breast carcinomas is still unknown. We investigated Rb2 protein expression in tumour tissue from 68 mammary and 41 endometrial carcinomas, 4 mammary cell lines, and normal tissue samples. Therefore, we performed Western blot experiments for Rb2, Rb, and the oestrogen and progesterone receptors (ER, PR-A, PR-B). Weak or absent Rb2 expression was more often found in endometrial (59%) than in mammary carcinomas (24%). We found significant positive correlations of Rb2 expression with Rb, ER, and PR-B in breast cancer samples, and of Rb2 with Rb, PR-A, PR-B, and younger age in endometrial carcinomas. No significant associations with histological grading, stage, nodal involvement, or Ki67 staining were detected. Rb2 mRNA expression was studied by semi-quantitative RT-PCR in 56 endometrial or mammary tissue samples and correlated significantly with Western blot results. Our results indicate that loss of Rb2 expression, mostly by transcriptional down-regulation, may be associated with the development and dedifferentiation of most endometrial and a subset of mammary carcinomas.

Expression of cyclin-dependent kinase inhibitors p16MTS1, p21WAF1, and p27KIP1 in HPV-positive and HPV-negative cervical adenocarcinomas

Inactivation or down-regulation of the cell-cycle inhibitors p16MTS1, p21WAF1, and p27KIP1 is involved in the carcinogenesis of various human tumors. In cervical squamous cell carcinomas that are associated with human papillomavirus (HPV) infection, the expression or function of these proteins is impaired by the action of viral oncoproteins E6 and E7. Comparably less is known about the role of these cyclin-dependent kinase inhibitors in cervical adenocarcinomas, 15-40% of which are HPV negative. Therefore, we studied the expression of p16MTS1, p21WAF1, and p27KIP1 by immunohistochemistry in 60 cervical adenocarcinomas. HPV infection was determined by PCR, and HPV 16 and 18 E6/E7 oncogene expression was analyzed by RNA-RNA in situ hybridization. We found significant correlations of strong p16 expression with HPV 16/18 infection and HPV 16/18 E6/E7 oncogene expression (P=0.001). Moderate or strong p16 expression was also observed in 41% of HPV-negative carcinomas, indicating that HPV-independent mechanisms might also lead to p16 overexpression. In addition, stronger p21 and p27 expression was significantly associated with the detection of HPV 16 or 18 E6/E7 transcripts (P=0.015 and 0.030, respectively). Obviously, the tumor suppressor action of these proteins can be overcome in HPV-positive lesions. In contrast, absent or low p16, p21, and p27 immunostaining was observed in most HPV-negative cervical adenocarcinomas and might contribute to carcinogenesis in these tumors.

Progesterone receptor isoforms, PR-B and PR-A, in breast cancer: correlations with clinicopathologic tumor parameters and expression of AP-1 factors

In the present study, we used Western blot analysis to determine the expression of the progesterone receptor (PR) isoforms, PR-B and PR-A, in breast tumors (n = 53), and correlated the expression patterns of the two isoforms with the clinicopathological parameters of these tumors and with expression of the AP-1 family of transcription factors. Expression of the two PR isoforms correlated significantly with each other, indicating that the expression of the two isoforms is probably regulated in a correlated fashion. Expression of both isoforms correlated significantly with expression of the estrogen receptor (ER). Furthermore, expression of PR-B was found to correlate significantly with the absence of ErbB2/neu. For the AP-1 factors, Fra-1 expression showed an inverse correlation with PR-B expression. In contrast, expression of FosB correlated significantly with expression of both isoforms, and the association was stronger with PR-B expression. An analysis of the ratio of expression of the two isoforms showed that most of the tumors expressed PR-A levels which were equal or higher than the corresponding PR-B expression levels (together 94% of the analyzed tumors) indicating that, in mammary carcinomas, a predominance of the PR-A isoform over the PR-B isoform seems to be the case. While there was no statistically significant correlation with age, staging and histological type, expression of both isoforms correlated with a more differentiated phenotype (G1/G2 grading). However, this association was stronger for PR-B. Also, a PR-A < or = PR-B expression level was associated with G1/G2 grading, while a PR-A > PR-B expression level showed an association with a more undifferentiated phenotype (G3 grading). The expression level of the two PR isoforms might prove to be of prognostic and/or predictive value, especially since the two isoforms have been shown to be functionally different and to modulate the response of tumor cells to progestins and antiprogestins differently.

Overexpression of the p16 cell cycle inhibitor in breast cancer is associated with a more malignant phenotype

In order to study the role of the p16INK4A(MTS1/CDKN2a) tumor suppressor in breast cancer, we analyzed p16 protein expression in 60 breast cancer samples which were also analyzed for expression of Rb, Ki67, HER2/neu, and estrogen and progesterone receptors (ER, PR). P16 expression was investigated by two methods: western blotting (WB) followed by densitometry, and immunohistochemistry (IHC). The Rb status was studied by western blotting, and expression of Ki67, HER2/neu, ER, and PR was analyzed immunohistochemically. P16-negative results were found in 18% of the carcinomas by WB, but in only one case by IHC and were not associated with established prognostic parameters. In contrast, p16 overexpression which was detected by WB and IHC in 15% and 25% of the tumors, respectively, was significantly associated with unfavorable prognostic indicators. High p16 expression as detected by both methods correlated significantly with high grading and a negative estrogen receptor status. In addition, a significant association of p16 staining with inverse progesterone receptor status and high Ki67 expression was found with IHC. No correlation of p16 expression with clinical stage, HER2/neu immunostaining, Rb expression or Rb phosphorylation was found. Comparison of western blot results and immunohistochemistry suggests that both nuclear and cytoplasmic immunoreactivity in tumor cells is specific and due to p16 expression. We conclude that high p16 reactivity (both nuclear andcytoplasmic) is indicative of a more undifferentiated, malignant phenotype in mammary carcinomas.

Differences in HPV 16- and HPV 18 E6/E7 oncogene expression between in situ and invasive adenocarcinomas of the cervix uteri

To evaluate the importance of high-risk human papillomavirus (HPV) types in in situ and invasive adeno- and adenosquamous carcinomas (ACISs/ACs, and ASCISs/ASCs) of the cervix uteri, we analyzed HPV infection and HPV 16- and HPV 18 E6/E7 oncogene expression in different histologic subtypes. Using the polymerase chain reaction (PCR) technique, 29 of 33 (88%) ACISs, 2 of 2 (100%) ASCISs, 46 of 54 (85%) ACs, and 8 of 10 (80%) ASCs were found to be HPV 16- and/or HPV 18-positive. In 25 of 35 (71%), 10 of 35 (29%), and 4 of 35 (11%) ACISs/ASCISs, HPV 16, HPV 18, and HPV 16 and HPV 18 were detected, respectively. Invasive ACs/ASCs were more frequently infected with HPV 18 (36 of 64, 56%) than with HPV 16 (28 of 64, 44%). Ten (16%) of these cases were positive for HPV 16 and HPV 18. In ACISs/ASCISs, HPV 16 oncogene expression predominated (62%) relative to HPV 18 (25%) expression, whereas in invasive ACs/ASCs, only 21% of the cases expressed HPV 16, but 48% of the cases expressed HPV 18 oncogenes. Thus, detection of HPV 18 in ACISs/ASCISs might be associated with an increased risk of progression. HPV oncogene expression was not dependent on histologic subtype of in situ or invasive AC. Normal glandular epithelia and glandular dysplasias (GDs, n = 4) were always negative concerning HPV oncogene expression. In HPV 16- and HPV 18-double-infected cases, HPV 18 oncogene expression was most frequently detected, and we did not find a coexpression of HPV 16- and HPV 18-specific oncogenes in purely glandular lesions or in cases with an additional CIN (cervical intraepithelial neoplasia) II or CIN III. HPV E6/E7 expression of the same HPV type in both in situ or invasive ACs and associated CIN II/III suggest that these lesions might be histogenetically related.

Association of human papillomavirus infection with carcinoma of the cervix uteri and its precursor lesions: theoretical and practical implications

Human papillomaviruses (HPVs) are the major aetiological agents of cervical carcinoma. In this review, epidemiological and molecular data are combined to present a model for HPV-induced cervical carcinogenesis. The impact of current knowledge regarding diagnostic and therapeutic approaches is shown, i.e. the use of HPV tests in cervical cancer screening, in the management of atypical smears of uncertain diagnosis and in smears indicative of mild dysplasias, as well as in follow-up examinations during and after therapy. In addition, the value of the two most frequently used HPV detection systems, polymerase-chain reaction (PCR) and hybrid capture (HC) analysis, is discussed.

Expression of cell cycle-regulatory proteins rb, p16/MTS1, p27/KIP1, p21/WAF1, cyclin D1 and cyclin E in breast cancer: correlations with expression of activating protein-1 family members

The activating protein-1 (AP-1) complex is a mitogen-activated composite transcription factor that leads to activation of various target genes and enhanced proliferation of many cells after stimulation by TPA, EGF, serum, etc. The molecular mechanism of cell-cycle activation by AP-1 complexes remains unclear. Therefore, we studied protein expression of 6 cell cycle-regulatory proteins (Rb, p16, p21, p27, cyclin D1, and cyclin E) in protein extracts from 53 breast cancer samples and 4 mammary cell lines and correlated the data with expression of the 7 AP-1 family members (c-jun, junB, junD, c-fos, fosB, fra-1, and fra-2) as determined in a previous study. After Western blot analysis, we found significant associations between members of both groups: whereas c-jun was associated with Rb expression (p = 0.002), strong junD and c-fos expression correlated with high cyclin E reactivity (p = 0.017 and p = 0.013, respectively). Over-expression of fosB was found mainly in tumors with strong Rb (p = 0.013) and weak p16 (p = 0.004) expression. Fra-1 expression was significantly associated with p16 and cyclin E over-expression, whereas fra-2 results correlated with both cyclin D1 and cyclin E. These results point to direct or indirect activation of some cell cycle-regulatory proteins by AP-1 complexes. In addition, our data suggest differential regulation of cell cycle-stimulating and -inhibiting factors depending on the abundance of single AP-1 family members.

Expression pattern of the AP-1 family in breast cancer: association of fosB expression with a well-differentiated, receptor-positive tumor phenotype

In the present study, the expression of members of the AP-1 family of transcription factors in breast tumors (n = 53) was investigated by Western blot with antibodies specific for each of the AP-1 family members (c-jun, junB, junD and c-fos, fosB, fra1 and fra2). The tumors were characterized with regard to grading, staging, histology, steroid-receptor-expression status and c-erbB2/neu expression. For comparison, normal breast-tissue samples, human breast-cancer cell lines (T47D and MDA-MB231) and the transformed human breast epithelial cell line HBL100 were also analyzed. For c-jun, junB, c-fos and fra2, a relatively uniform expression pattern without significant differences among tumors was observed. junD-protein amounts varied strongly in the tumor specimens. fosB-expression levels also varied strongly in the tumors, weak/absent expression being found in 47%, while 45% exhibited strong/very strong levels of expression. While none of the other AP-1 family members showed significant correlations with clinico-pathological tumor parameters or receptor status, expression of fosB was found to correlate significantly with positive steroid-hormone-receptor status (in the tumors and the cell lines) and a more differentiated tumor phenotype. Expression of 2 fra-1-specific bands of 33 and 36.5 kDa showed significant negative correlation with fosB expression, as well as with estrogen-receptor status and differentiation. We conclude that strong differences in the expression pattern of AP-1 family members are present in breast tumors, and that certain members of this family, such as fosB and fra-1, might be involved in the pathogenesis of these tumors.

Strongly reduced expression of the cell cycle inhibitor p27 in endometrial neoplasia

In the present study we investigated the expression of the cell cycle inhibitor p27 in endometrial neoplasia using immunohistochemistry with a p27-specific antibody. Expression of p27 in endometrial carcinomas was compared with expression in the normal endometrium throughout the cycle. Normal endometrial cells showed strong nuclear expression of p27. Expression was present throughout the cycle and was stronger during the secretory phase. We found strongly reduced or abolished expression of p27 in endometrial carcinoma (85.3% of cases). The 41 tumours analysed were classified according to p27 staining intensity and percentage of positive cells into the following categories of p27 expression: negative/very low (56.0%); low (29.3%); moderate (14.7%) and high (0.0%). All the p27-positive tumours were well-differentiated endometrioid carcinomas of malignancy grade G1. Comparison with the p53 status showed that all tumours with strong p53 expression had low/negative p27 staining, while those that were positive for p27 had negative/low p53 staining. Reduced or absent p27 levels were also observed by Western blot analysis both in tumour samples and in HEC-1B endometrial adenocarcinoma cells. It thus seems that p27 expression is essential for the control of normal endometrial proliferation, and reduced or absent p27 expression may be an important step in endometrial carcinogenesis.

[Natural course of HPV infection. Usefulness of HPV analysis in cervix diagnosis]

Cervical carcinomas and their precursors (cervical dysplasia, CIN1-3) are associated with human papillomavirus (HPV) infections. Epidemiological and in vitro-studies have shown that some of the genital HPV types, the high risk-types 16, 18, 31 etc., code for proteins (E6/E7) which strongly influence the cell cycle and genome stability. Progression from weak to severe dysplasia and to invasive cancer is associated with increasing expression of these viral oncogenes. Which additional cofactors contribute to progression of some dysplasias to carcinomas is still a matter of investigation. Recent results point to genetic predisposition (p53 polymorphism), cellular immune reaction, and cytokine expression. For HPV detection in cervical swabs and biopsies two highly sensitive and reliable systems (PCR, Hybrid Capture system) are available. Although classical histological methods are sufficient for the diagnosis of high-grade lesions and invasive cancer, HPV testing might give valuable diagnostic and prognostic clues especially in cases of unclear cytology (ASCUS) or weak dysplasia.

P16/MTS1 and pRB expression in endometrial carcinomas

p16MTS1/CDKN1 and the retinoblastoma protein Rb are both involved in negative regulation of G1/S progression in the mammalian cell cycle. Inactivation of one of these tumour suppressor genes is involved in many malignant tumours, and in some studies a negative correlation of p16 and Rb expression has been found. In order to study this interaction in endometrial carcinogenesis, we investigated 36 endometrial carcinomas, 11 cases of hyperplasia, 23 normal endometrial samples, and two uterine carcinoma cell lines by immunohistochemistry or RT-PCR. Rb was expressed in normal endometrial epithelium, hyperplasia, cell lines, and most carcinomas; negative immunostaining was only detected in 1 of 36 tumours. In contrast, p16 expression was weak in normal endometrium and increased in most cases of hyperplasia, but negative or minimally positive in 74% of the carcinomas and the Hec1B adenocarcinoma cell line, and there was no significant association with Rb immunostaining. Strikingly high p16 expression was found in foci of squamous metaplasia within hyperplastic or carcinomatous tissue. Deletion and mutation analysis of the p16 gene was performed in DNA from microdissected tumour samples and cell lines. No p16 deletion was found, and mutations were detected in only one tumour sample and Skut1B uterine mixed mesodermal tumour cells. Our data indicate that in spite of low or absent p16 expression, genetic alterations of the p16 and Rb tumour suppressor genes are rare in endometrial carcinogenesis.

p16/MTS1 inactivation in ovarian carcinomas: high frequency of reduced protein expression associated with hyper-methylation or mutation in endometrioid and mucinous tumors

Inactivation of the tumor-suppressor gene p16 (MTS1/ CDKN2/INK4a) has been described in various human malignancies. Although p16 deletion has been found in various ovarian tumor cell lines, p16 inactivation by homozygous deletion or mutation has been reported only sporadically in primary ovarian carcinomas. In a comprehensive study, we analyzed p16 protein expression by immuno-histochemistry (IHC) on paraffin sections of 94 primary ovarian carcinomas of different histological subtype. Loss of expression was detected in 19 primary tumors (20%), mainly mucinous and endometrioid carcinomas. To reveal the cause of suppressed expression, we performed (i) analysis of homozygous deletions by comparative PCR after micro-dissection, (ii) mutation analysis by single-strand conformation polymorphism analysis and subsequent direct sequencing and (iii) methylation-specific PCR to determine the methylation status of 5'-CpG islands. Loss of or weak p16 expression was caused by hyper-methylation (12/19 IHC-negative cases), somatic mutation (10 tumors) or homozygous deletion (1 case). Aberrant p 16 results by one of these methods were detected in 71-79% of endometrioid and mucinous, but in only 10% of serous-papillary, carcinomas. Our data suggest that p16 inactivation is a typical feature of certain subtypes of ovarian carcinoma.

Molecular and immunohistochemical analysis of p53 mutations in scrapings and tissue from preinvasive and invasive breast cancer

Mutations of the p53 gene appear to be one of the most common abnormalities in human cancer. Although many studies have been published about p53 alterations in breast cancer, data on molecular biological detection of p53 mutations in in situ lesions are still rare, and the implications for breast cancerogenesis are unclear. Tissue samples from 83 patients with different stages of breast cancer and from 13 patients with benign breast lesions were screened for p53 gene mutations by polymerase chain reaction (PCR) followed by temperature-gradient gel electrophoresis (TGGE). p53 protein accumulation was analysed by immunohistochemistry (IHC). Samples were gained from fresh-frozen tissue, scrapings, or paraffin embedded tissue. Additionally, 23 pairs of primary tumours and corresponding lymph nodes were examined. p53 gene aberrations were found in 55.7% of the infiltrating carcinomas, in 31.5% of the ductal carcinomas in situ (DCIS) and in one atypical ductal hyperplasia. A positive correlation was seen with high-grade tumours and with comedo. There was no statistically significant relationship with respect to age, menopausal status, tumour size, hormone receptor status or lymphatic invasion. Concordance between TGGE and IHC was seen in only 63% of the cases analysed. However, with regard to p53 mutation screening by TGGE, a high significance (P = 0.0008) was seen between standard tissue extraction and our scrape preparation technique. Among 8 pairs of primary tumours and their corresponding lymph node metastases, only 3 harbored identical p53 mutations in the same exon, while in 5 cases with mutant p53 in the primaries, no mutation was seen in the lymph node. Our data indicate that p53 mutations are frequent in breast tumours associated with unfavorable prognosis, including high-grade or the comedo histotype. There is evidence that p53 gene alterations occur early in breast cancerogenesis, as mutations were detected not only in in situ carcinomas but also in atypical ductal hyperplasia.

p53 is a persistent and predictive marker in advanced ovarian carcinomas: multivariate analysis including comparison with Ki67 immunoreactivity

p53 mutation and p53 protein overexpression are common findings in ovarian carcinomas. In order to evaluate the prognostic significance of the p53 status and its role in metastasis, we examined 104 ovarian carcinomas, among them 83 cases with follow-up data, and 40 pairs of primary tumors and metastases, by p53 immunohistochemistry and temperature-gradient gel electrophoresis. Comparison of primary tumors and their metastases revealed identical results in 88%-90% of the cases, indicating that, in most cases, mutant p53 occurs prior to metastatic spread and remains clonally conserved. With respect to all tumors, moderate/high p53 expression was significantly more prevalent in serous-papillary types, carcinomas with high grade, and high Ki67 scores, but was not associated with age, stage, or hormone receptor status. Kaplan-Meier analysis of 83 cases, followed-up for 9-96 months, demonstrated that moderate/high p53 overexpression in the group of 66 stage T3/M1 tumors was associated significantly (P = 0.0028 and P = 0.0105) with shorter overall and recurrence-free survival. Multivariate analysis revealed that advanced clinical stage and p53 positivity were the only independent predictive variables. No significance was seen in regard to second-look results and outcome of 50 patients receiving platinum-based chemotherapy. These observations show that p52 immunohistochemistry is an independent prognostic indicator at the given cut-off level, but does not reliably predict chemotherapy response.

Demonstration of p53 protein and TP53 gene mutations in oligodendrogliomas

Paraffin embedded tissue of 84 oligodendrogliomas (63 primary tumours, 21 recurrences), 21 glioblastomas with oligodendroglial growth pattern (15 primaries, 6 recurrences) and 17 mixed gliomas was investigated for the presence of mutations in exons 5-9 by means of single stranded conformation polymorphism (SCCP), temperature gradient gel electrophoresis (TGGE) and direct DNA sequencing. In parallel, p53 protein accumulation was determined by means of immunohistochemistry. The percentage of mutations was found to be higher than previously reported (6 of 44 grade II oligodendrogliomas, 4 of 19 grade III oligodendrogliomas, 4 of 15 glioblastomas). In 4 cases, the mutations lead to distinct changes in the primary or secondary structure of the protein (cysteine-->tyrosine, proline-->leucine) and were associated with marked accumulation of p53 protein. A significant correlation between p53 protein accumulation and TP53 gene aberrations was found (P < 0.001), although p53 protein accumulation was detected more often than TP53 gene anomalies, indicating that factors other than TP53 gene mutation may also lead to a p53 protein accumulation in the tumour cells. A significant correlation was found for p53 protein accumulation and tumour grade but not TP53 gene mutations. In conclusion, evaluation of p53 protein accumulation reflected the clinical course of oligodendrogliomas better than the mere presence of TP53 gene mutations.