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Kerstin Junker

Publications and source records attributed to Kerstin Junker.

At least 19 recordsLinked to original sources
PubMed2026

Integrating NECTIN4 Amplification With Membranous Nectin-4 Expression to Develop a Scoring System for Predicting Enfortumab Vedotin Response in Urothelial Carcinoma.

PURPOSE: Enfortumab vedotin (EV) is standard therapy for metastatic urothelial carcinoma (mUC), yet the predictive relevance of NECTIN4 expression-especially membranous versus cytoplasmic-remains unclear. Here, we sought to extend previous findings on NECTIN4 gene amplification in parallel with a systematic subcellular evaluation of NECTIN4 expression. EXPERIMENTAL DESIGN: We retrospectively analyzed 179 EV-treated mUC patients. NECTIN4 amplification was assessed by FISH and NECTIN4 protein levels by IHC. A four-tier membranous scoring algorithm (0,1+,2+,3+) adapted from CAP HER2 gastric guidelines was benchmarked against H-score. We integrated amplification status with membranous staining to refine predictive stratification and compared associations with objective response rate (ORR) to EV-301 data. RESULTS: Combining membranous and cytoplasmic compartments resulted in a median composite H-score of 260 (78.2% &#x2265;150), closely matching NECTIN4 expression prevalence reported in EV-301 (median 250; 82.6% &#x2265; 150). A &#x2265;150 cut-off enriched for EV responders in both cohorts; in EV-301 with ORR of 45.8% vs. 20% (P = 0.001). High membranous expression based on the scoring (2+/3+) predicted response (ORR 55.1% vs. 25.5%; P < 0.001), with longer PFS (7.1 vs. 2.9 months; HR 0.45) and OS (12.3 vs. 6.9 months; HR 0.57), whereas cytoplasmic expression lacked predictive value. NECTIN4-amplified tumors showed particularly favorable outcomes (PFS 12.2 months; OS 30.1 months). An integrated three-tier model-amplified, non-amplified/high-membranous, and non-amplified/low-membranous-yielded ORRs of 77.2%, 42.9%, and 26.1% and separated survival outcomes. CONCLUSIONS: Our NECTIN4 scoring system integrating NECTIN4 amplification with membranous NECTIN4 expression accurately predicts outcomes, supporting combined genomic and membranous assessment as complementary biomarkers for optimizing EV selection.

Journal Article↗
PubMed2006

Prediction of renal allograft rejection by urinary protein analysis using ProteinChip Arrays (surface-enhanced laser desorption/ionization time-of-flight mass spectrometry).

OBJECTIVES: To develop a noninvasive method for the detection of renal transplant rejection using ProteinChip Arrays (surface-enhanced laser desorption/ionization time-of-flight mass spectrometry). METHODS: A total of 23 urine samples were collected from 13 patients showing biopsy-proven renal allograft rejection and from 10 patients without histologic signs of rejection. All 23 patients had clinical symptoms and signs of acute allograft rejection and underwent renal biopsy. Samples were centrifuged, and supernatants were directly spotted onto the ProteinChip arrays with different chromatographic surfaces. The obtained spectra in a range from 2 to 200 kDa were subjected to bioinformatic analysis using the method of Fuzzy c-means, followed by the establishment of rule bases and evaluation using the relevance index according to Kiendl. RESULTS: Several protein peaks were identified allowing differentiation between rejection and no rejection. Using two different ProteinChip surfaces, we found two biomarkers at 25.71 kDa and 28.13 kDa that gave a diagnostic sensitivity of 90% and 93% and a specificity of 80% (SAX2) and 85% (CM10), respectively. CONCLUSIONS: Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry appears to be a promising new diagnostic tool for distinguishing renal transplant patients with no rejection from those with acute rejection.

Graft Rejection↗
PubMed2006

Immune escape for renal cell carcinoma: CD70 mediates apoptosis in lymphocytes.

Tumors can escape immune recognition and destruction through the induction of apoptosis in lymphocytes. Although renal cell carcinoma (RCC) is able to prevent immune recognition, only a few genes (such as FasL) that are relevant for RCC immune escape have been identified so far. We have previously shown that some apoptosis-inducing genes are overexpressed in RCC. We hypothesized that these genes could be part of the immune-escape strategy of these tumors. Here we report that CD70, a cytokine overexpressed in RCC, promotes lymphocyte apoptosis through interaction with its receptor CD27 and with the intracellular receptor-binding protein SIVA. Apoptosis increased after cocultivating lymphocytes with the RCC cell lines A498 and CAKI2. The addition of recombinant soluble CD70 to both native lymphocytes and a T-cell cell line resulted in increased lymphocyte apoptosis as well. Furthermore, induced apoptosis could be partially blocked with anti-CD27 and anti-CD70 antibodies. Our results strongly indicate a role for CD70 and CD27 receptor in lymphocyte apoptosis within the tumor environment. Apoptosis mediated by exposure to the CD70 secreted by tumor cells may contribute to the failure of RCC patients to develop an effective lymphocyte-mediated antitumor response.

Apoptosis↗
PubMed2006

PAR-type thrombin receptors in renal carcinoma cells: PAR1-mediated EGFR activation promotes cell migration.

Cross-talk between G-protein-coupled receptor (GPCR) and epidermal growth factor receptor (EGFR) signaling systems is established in a wide variety of normal and neoplastic cell types. Here, we show that proteinase-activated receptor 1 (PAR1) mediates the tyrosine phosphorylation of EGFR in human renal carcinoma cells expressing PAR1 and PAR3 endogeneously. This GPCR-EGFR signal transduction pathway cross-talk requires matrix metalloproteinase activity and is involved in the regulation of renal carcinoma cell migration across a collagen barrier as shown using a Boyden chamber type assay. Our data therefore document a regulatory role of PAR1-mediated EGFR transactivation in cancer cell chemotactic migration. Further, our results underline the importance of PAR1-mediated pathways in kidney cancer cells and suggest that the thrombin/PAR1 system mediating EGFR transactivation may play a role in the progression of this tumor entity.

Cell Line, Tumor↗
PubMed2006

Comparative transcriptional and functional profiling of clear cell and papillary renal cell carcinoma.

Renal cell carcinoma (RCC) is known to effectively prevent immune recognition. However, little is known about the mechanisms that underlie this phenomenon. Thus, the identification of immunogenic molecules associated with RCC and the elucidation of the corresponding signaling pathways are crucial to the development of effective treatments. We performed transcriptional and functional profiling with cDNA microarrays (1070 cDNA probes) on a total of 17 RCCs, 11 clear cell and 6 papillary, and on corresponding normal tissue. Samples were clustered based on their expression profiles. We found a total of 45 genes to be regulated equally by both tumor types compared to the normal tissue. A set of 13 differentially expressed genes was identified between the examined tumor subtypes. Functional analysis was performed for both gene sets and showed a significant enrichment of cell surface genes regulated in both tumor subtypes. Within these we found five surface marker genes to be upregulated (TNFRSF10B, CD70, TNFR1, PDGFRB, and BAFF) which are involved in immune responses via the regulation of lymphocytes and can also induce apoptosis. Their overexpression in both tumor subtypes suggests a possible involvement in the immune escape strategies of RCC. The combination of transcriptional and functional profiling revealed potential target molecules for novel therapy strategies that must be studied in more detail.

Carcinoma, Papillary↗
PubMed2005

Molecular evidence for progression of nephrogenic metaplasia of the urinary bladder to clear cell adenocarcinoma.

Nephrogenic metaplasia or nephrogenic adenoma of the urinary tract may present a diagnostic challenge in surgical pathology practice. Previous case reports suggest the possibility of nephrogenic metaplasia progressing to clear cell adenocarcinoma, but a malignant potential of nephrogenic metaplasia is generally not acknowledged. A case of a 70-year-old female patient with multiple recurrences of nephrogenic metaplasia of the urinary bladder and subsequent development of clear cell adenocarcinoma is described. Immunohistochemical studies help to differentiate the 2 entities. Results of molecular studies, particularly comparative genomic hybridization analysis, suggest clonal evolution of nephrogenic metaplasia to clear cell adenocarcinoma in this case.

Adenocarcinoma, Clear Cell↗
PubMed2005

Identification of CD70 as a diagnostic biomarker for clear cell renal cell carcinoma by gene expression profiling, real-time RT-PCR and immunohistochemistry.

The underlying molecular mechanisms of renal cell carcinoma (RCC) are poorly understood and more reliable markers for early diagnosis are needed. Hence, alternative strategies for biomarker discovery with appropriate validation technologies have to be performed. To elucidate genesis and progression of RCC we used high parallel chip based gene expression profiling comparing normal and tumour tissues. We compared corresponding control and tumour tissue samples from 10 patients with clear cell RCC. We isolated RNA from histologically well characterised tissue sections and performed reverse transcription, labelling and linear RNA amplification. Samples were hybridised on microarrays containing 642 human cDNAs. Of the 352 differentially expressed genes found, CD70 and FRA2 were selected for further evaluation by real-time RT-PCR. The analysis all showed a high potential to discriminate between normal and tumour tissue. Moreover, increased CD70 mRNA expression in tumour cells could be correlated to its expression at the protein level. Immunohistochemistry (IHC) showed very strong expression of CD70 in all tumour samples but no expression in adjacent normal kidney tissue. With our combined approach we were able to identify CD70 as a new marker for RCC, which may be useful in the future for improved immunohistochemical diagnosis.

Antigens, CD↗
PubMed2005

CD70: a new tumor specific biomarker for renal cell carcinoma.

PURPOSE: To date there have been no specific tumor markers available for the differential diagnosis of renal cell carcinoma (RCC). In an earlier study we identified high RNA expression of CD70 in clear cell RCC. CD70 is a type II transmembrane protein belonging to the tumor necrosis factor family. It represents the ligand for CD27, a glycosylated transmembrane protein of the tumor necrosis factor receptor family. To our knowledge the function of CD70 in solid tumors is not known. In the current study we analyzed CD70 protein expression in different RCC subtypes. MATERIALS AND METHODS: A total of 68 tumor samples of different histopathological subtypes were investigated by immunochemistry, including 41 clear cell, 19 papillary and 5 chromophobe RCCs, and 3 oncocytomas as well as their normal tissue counterparts. Immunochemistry was performed on frozen tissue samples using monoclonal antibody against CD70. RESULTS: None of the normal kidney tissues showed CD70 expression. In contrast, all clear cell RCCs expressed CD70 at a high level. Positive immunostaining was observed in 1 papillary (5%) and in 1 chromophobe (20%) RCC. Five papillary tumor samples (26%) showed focal staining in less than 5% of cells. All other samples were negative for CD70. CONCLUSIONS: Our study identified CD70 as a new specific tumor marker for clear cell RCC. This new marker can be used for differential diagnosis in cases of uncertain histological classification. The function of this protein in tumorigenesis and its use as a diagnostic marker in serum and urine or as a therapeutic tool must be investigated in further studies.

Adenocarcinoma, Clear Cell↗
PubMed2005

The accuracy of 250 fine needle biopsies of renal tumors.

PURPOSE: In some cases of uncertain lesions in the kidney it would be helpful to perform biopsies for preoperative histopathological evaluation. In this study we evaluated the accuracy of and the impact on tumor management of core biopsy for histopathological evaluation of small solid renal masses. MATERIALS AND METHODS: After radical or partial nephrectomy 250 renal tumor biopsies were performed in 50 patients. All biopsies were performed by 1 urologist after preparation of the kidney ex situ on back table visually guided. Formalin fixed paraffin embedded biopsies were evaluated by 1 pathologist. RESULTS: In 49 of 50 cases (98%) we could define the malignant behavior of the tumor when performing 1 central and 4 peripheral biopsies of each tumor. In 85.2% the grading was correctly defined. A benign lesion was revealed in 4 cases (8%, all oncocytoma). In renal tumors 4 cm or smaller in diameter the accuracy of 1 central and 1 peripheral biopsy each regarding definition of tumor origin, tumor grading and cell type/growth pattern was 96% and 95.5%, 84% and 84.4%, and 87.5% and 89.5%, respectively. In renal tumors more than 4 cm in diameter the accuracy was 100% and 98.1%, 85% and 94.3%, and 71.4% and 88.7%, respectively. CONCLUSIONS: Core biopsy of renal lesions is accurate enough for histopathological evaluation and determination of therapeutic procedure. Additionally, biopsy could be used for identifying benign renal lesion for observation.

Biopsy, Needle↗
PubMed2005

Identification of tumor entities of renal cell carcinoma using interphase fluorescence in situ hybridization.

PURPOSE: We developed a rapid interphase fluorescence in situ hybridization (FISH) test to differentiate renal cell carcinoma (RCC) based on known genetic alterations and verified the suitability of this test for practical use. MATERIALS AND METHODS: We composed 2 FISH test sets using 6 centromere specific and 2 region specific DNA probes of human chromosomes. Test set 1 contained centromeric probes for chromosomes 1, 2, 6 and 9, as labeled by 4 fluorescence dyes. For test set 2 we chose 3p24pter and 3p13p14 regions, and centromeric probes of chromosomes 7 and 17. Interphase nuclei of tumor specimens were prepared from 50 mum frozen tissue sections and fixed on slides. The 2 sets were hybridized simultaneously side by side on the same slide. RESULTS: Seven clear cell carcinomas, 8 papillary carcinomas, 7 chromophobe RCCs and 3 oncocytomas were analyzed by interphase FISH. Results were compared with comparative genomic hybridization findings and pathological reports. Genetic alterations were detected in 22 of 25 analyzed tumors by FISH. FISH findings absolutely correlated with comparative genomic hybridization results. Of the analyzed carcinomas 22 could be identified correctly. In 3 tumors the histological subtypes were revised. CONCLUSIONS: The results of this study demonstrate that the performed test set allows the accurate identification of RCC in 1 hybridization step. Therefore, FISH represents an effective method for the rapid classification of RCC.

Carcinoma, Renal Cell↗
PubMed2005

Identification of protein pattern in kidney cancer using ProteinChip arrays and bioinformatics.

Tumor biology of renal cell carcinoma (RCC) is not very well understood, although many studies on molecular and cellular biology have been performed. It is accepted now that cancer research has to be performed also with proteomic tools, because proteins are the real actors in the genesis and progression of cancer. Therefore, we used a ProteinChip System(R) (SELDI) which is able to detect minute amounts of protein and moreover to analyze a complex protein pattern. We analyzed 37 cases of clear cell RCC as a training set including corresponding normal tissue. From all samples protein lysates were made and spotted directly on different chip surfaces (SAX2, WCX). After a washing procedure the arrays were analyzed in the ProteinChip Reader. All profiles were subjected to a bioinformatical analysis including normalization, clustering, rule extraction and rating. Defined rules (markers) were evaluated using a test set of 24 samples (13 tumor tissues and 11 normal kidney tissues). The generated rule base for the SAX2 surface showed a sensitivity of 100% and a specificity of 97.3%. For the WCX arrays the optimal rule base showed worse results. A combined rule base for SAX2 and WCX did not result in a higher sensitivity or specificity. Using the optimal rule base for the SAX2 chip in the test set, sensitivity and specificity reached 76.9% and 100%, respectively. The ProteinChip System represents a key technology for the rapid detection of cancer specific proteomic patterns. It is possible to identify clear cell renal cancer with high sensitivity and specificity from minimal amounts of cells.

Cell Line, Tumor↗
PubMed2005

Molecular clonal analysis of recurrent bladder cancer.

In order to select the optimum therapy for patients at risk of recurrent bladder cancer, it is necessary to know the pathway of recurrence development. However, the origin of recurrent bladder cancer is controversially discussed. Therefore, the aim of our study was to define the clonal origin of recurrent tumors of the bladder using molecular genetic markers. Thirty cases with recurrent bladder cancer (1-4 recurrences per case) were investigated by microsatellite analysis using 4 markers for chromosome 9. PCR was performed according to standard protocols followed by gel electrophoresis and automated analysis using an automated DNA-Sequencer (LI-QOR). In 25 of 30 cases, loss of heterozygosity (LOH) occurred in at least 1 tumor. Identical LOH was detected in 20 cases. In all these cases the same allele was affected. Different LOH patterns were found in 4 cases showing LOH in only 1 tumor and in 1 case with alterations of different markers. In 5 cases, no alterations were detected using these markers. Our results show that the majority of bladder cancer recurrences are characterized by monoclonal origin. These data indicate that recurrence is caused by cell dissemination from the original tumor. For that reason, an early instillation therapy should be performed after transurethral resection.

Chromosomes, Human, Pair 9↗
PubMed2005

Comparative study of renal cell carcinoma by CGH, multicolor-FISH and conventional cytogenic banding analysis.

Using different cytogenetic techniques in combination is crucial to studying the high complexity of genetic rearrangements in tumor cells. The 8 clear cell (cc) and 5 papillary (p) renal cell carcinomas (RCC) were analyzed using multicolor fluorescence in situ hybridization (multicolor-FISH), conventional Giemsa banding (G-banding) and comparative genomic hybridization (CGH) analysis. CGH analysis was carried out with DNA from frozen tissue sections and short-term cultures of primary tumors. Using CGH analysis, both tissue sections and cell cultures of ccRCC showed the typical chromosomal changes such as the loss of 3p, 4q, 6q, 8p, 9q, 14 and a gain of 5q and 7. Most imbalances detected by CGH in cell culture could be deciphered by multicolor-FISH and G-banding analysis as unbalanced trans-locations t(3;6)(p11.1;p11.1), t(8;14)(p11.1;q11.1), t(3;5) (p14;q21-22), t(1;15)(p11;q11.1), t(3;15)(p11;q11.1)t(8;17) (p11.1;q11.1), t(8;17)(q22;p11.1). Only one balanced trans-location t(9;18)(q34;q11.1) was shown in ccRCC. CGH of papillary RCC displayed mostly gains of whole chromosomes 7, 12, 16 and 17 and a loss of chromosome Y. There was 1 papillary RCC that displayed a partial gain of chromosome 7, showing an unbalanced translocation t(7;11)(q11.1;q25). The balanced translocations t(2;9)(q11.1;q34) and t(7;15) (q22 approximately 31;q21-22) were registered in pRCC. The combined analysis of RCC by different methods allowed a more accurate characterization of the complex karyotypes of tumor tissue, and offered a comprehensive description of given tumors.

Azure Stains↗
PubMed2004

Genetic profile of bone metastases in renal cell carcinoma.

OBJECTIVE: The aim of this study was to define specific genetic alterations which are common in bone metastases in renal cancer patients. METHODS: Tumor DNA from 31 metastases and 13 related primary tumors was extracted from paraffin embedded tissue sections. DOP-PCR was performed to amplify the whole DNA. After labelling by PCR, CGH was performed according to standard protocols. RESULTS: The mean number of aberrations per metastasis was 6.3 (1-13). Losses of chromosomes 3p (76%), 6 (20%), 8p (20%), 9 (34%), 14q (27%) and 18 (20%) as well as gains of chromosomes 5 (45%), 8q (34%) and 17 (27%) were detected frequently. Thirteen related primary tumors were also investigated. In 7 cases, at least one identical alteration was found in both primary tumor and metastases. In these cases, the number of alterations was mostly higher in primary tumors than in metastases without statistical significance. However, in general, the frequency of alterations was higher in metastases. CONCLUSIONS: Bone metastases from renal cell carcinoma are characterized by typical genetic alterations. Changes leading to metastasizing happen early in tumor pathogenesis. However, further accumulation of genetic changes occurs in metastases leading to a more complex genetic pattern which might be necessary for progression to clinically relevant metastases.

Bone Neoplasms↗
PubMed2003

Genetic subtyping of renal cell carcinoma by comparative genomic hybridization.

The prognosis of renal cell carcinoma (RCC) varies dependent on histologic tumor subtypes. However, differentiation between RCC types may sometimes be difficult on histologic grounds alone. Furthermore, the prognostic value of histologic parameters for the individual prognosis is limited. Additional information on the molecular level seems necessary to obtain more certainty in diagnostic and prognostic evaluation. By investigating genetic alterations in different RCC subtypes, we sought to obtain a genotype-phenotype correlation. Eighty-two clear-cell, 53 papillary, 23 chromophobe RCCs and 26 renal oncocytomas were investigated. Comparative genomic hybridization (CGH) was performed on DNA from paraffin-embedded tissue samples. DNA was isolated from tumor areas by microdissection and amplified by degenerated oligonucleotide primed polymerase chain reaction (DOP-PCR). CGH was performed according to standard protocols. We were able to detect specific alterations in each RCC subtype: clear cell RCC showed -3p, +5/5q, -8p, -9, -14, -18; papillary (chromophilic) RCC gains of chromosomes 7, 17, 16, 3, 12; chromophobe RCC loss of chromosomes 1, 2, 6, 10, 13, 17, 21; renal oncocytomas loss of chromosomes 1/1p and 14. Furthermore, for clear cell RCC, it was possible to define alterations which are associated with metastatic disease: loss of 9, 10, 14. Our results demonstrate that each RCC subtype is characterized by distinct genetic alterations. The definition of genetic alterations seems helpful for a tumor typing especially when morphology is equivocal. Therefore, genetic analyses represent a powerful diagnostic and prognostic tool for RCC.

Carcinoma, Renal Cell↗
PubMed2003

Analysis of genetic alterations in normal bladder urothelium.

OBJECTIVES: To determine whether normal mucosa had already acquired genetic changes, we analyzed the loss of heterozygosity (LOH) and chromosomal changes in normal urothelium from patients with bladder cancer and those without any history of bladder cancer. METHODS: Sixteen patients with bladder cancer and 15 patients with benign prostatic hyperplasia were included in this study. Tumor tissue, as well as macroscopically normal mucosa, was examined histopathologically. We performed comparative genomic hybridization according to standard protocols to detect chromosomal alterations. Furthermore, we analyzed LOH using four markers on chromosome 9 according to standard protocols for polymerase chain reaction. RESULTS: In 75% of tumor samples, LOH or shifts were detected at least with one marker on chromosome 9. Comparative genomic hybridization revealed chromosomal alterations in 12 (75%) of 16 tumors. The loss of chromosome 9 was seen frequently (56%). LOH was observed in normal mucosa in 5 of 16 patients with tumor and 1 of 15 patients with benign prostatic hyperplasia. Chromosomal alterations were also seen in the normal mucosa of 1 patient with tumor and 2 patients with benign prostatic hyperplasia (chromosomes 1, 2, 6, 14, and 17). CONCLUSIONS: Our results indicated that no general genetic instability is present in the bladder urothelium. Therefore, in most patients with bladder cancer, it seems that multifocality and recurrence are not caused by genetic instability of normal urothelial cells but develop owing to cell migration or intraluminal spread.

Aged↗
PubMed2002

Frequent microsatellite instability in sporadic tumors of the upper urinary tract.

Urothelial carcinoma of the renal pelvis and ureter may develop sporadically or as a manifestation of hereditary nonpolyposis colorectal cancer. The majority of hereditary nonpolyposis colorectal cancer is caused by mutation of the human DNA mismatch repair (MMR) genes and is detected by associated microsatellite instability (MSI). Seventy-three unselected urothelial carcinomas of the ureter and/or renal pelvis were screened for MSI using the National Cancer Institute-designated reference panel (plus BAT40). Instability of at least two microsatellite markers (MSI-high) was detected in 15 samples (21%). Immunohistochemical staining of the MMR proteins (hMSH2, hMLH1, or hMSH6) was absent in 13 of 15 (87%) MSI tumors, and alteration of coding sequence microsatellites (TGFbetaRII, Bax, hMSH3, and hMSH6) was found at frequencies of 7-33% in these samples. Tumors with MSI had significantly different clinical and histopathological features including higher prevalence in female patients, low tumor stage and grade, and a papillary and frequently inverted growth pattern. Our results suggest a molecular pathway of tumorigenesis that is similar to MMR-deficient colorectal cancers and consistent with the notion that the site distributions of hereditary or sporadic MSI-high tumors may reflect tissue-specific susceptibility to lesions processed by the MMR machinery.

Adaptor Proteins, Signal Transducing↗