Ralf Hildenbrand

Lack of clinical efficacy of imatinib in metastatic melanoma

This two-centre phase-II trial aimed at investigating the efficacy of imatinib in metastasised melanoma patients in correlation to the tumour expression profile of the imatinib targets c-kit and platelet-derived growth factor receptor (PDGF-R). The primary study end point was objective response according to RECIST, secondary end points were safety, overall and progression-free survival. In all, 18 patients with treatment-refractory advanced melanoma received imatinib 800 mg day−1. In 16 evaluable patients no objective responses could be observed. The median overall survival was 3.9 months, the median time to progression was 1.9 months. Tumour biopsy specimens were obtained from 12 patients prior to imatinib therapy and analysed for c-kit, PDGF-Rα and -Rβ expression by immunohistochemistry. In four cases, cell lines established from these tumour specimens were tested for the antiproliferative effects of imatinib and for functional mutations of genes encoding the imatinib target molecules. The tumour specimens stained positive for CD117/c-kit in nine out of 12 cases (75%), for PDGF-Rα in seven out of 12 cases (58%) and for PDGF-Rβ in eight out of 12 cases (67%). The melanoma cell lines showed a heterogenous expression of the imatinib target molecules without functional mutations in the corresponding amino-acid sequences. In vitro imatinib treatment of the cell lines showed no antiproliferative effect. In conclusion, this study did not reveal an efficacy of imatinib in advanced metastatic melanoma, regardless of the expression pattern of the imatinib target molecules c-kit and PDGF-R.

High expression of vascular endothelial growth factor predicts early recurrence and poor prognosis after curative resection for ductal adenocarcinoma of the pancreas.

Introduction and Aims Only curative resection for pancreatic adenocarcinoma is related to a favorable prognosis, but the overall survival after surgery still remains poor, and early recurrence is frequently observed. Because recurrence is the limiting factor and the main cause of death after curative resection, the identification of markers that predict early postoperative recurrence is of paramount importance. Angiogenesis is essential for tumor growth and metastases; therefore, we set out to clarify whether vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) correlate with early recurrence and poor prognosis after curative resection. A second goal was to characterize the VEGF-producing cells and the subcellular distribution. Methodology Seventy patients with ductal adenocarcinoma of the pancreas were studied after curative resection with a follow-up of at least 2 years. The MVD quantification was performed immunohistochemically with use of a monoclonal antibody to CD34. The VEGF expression was studied with use of polyclonal antibody. To detect the intracellular localization of specific VEGF mRNA sequences, nonisotopic in situ hybridization was performed. The correlations among VEGF expression and MVD, clinicopathologic parameters, and clinical outcome were then statistically analyzed. Results The VEGF immunoreactivity was 88.6%, and positive mRNA signals were obtained in the cytoplasm of carcinoma and endothelial cells in 81.4%. Furthermore, we observed tumor-associated macrophages close to infiltrating carcinoma cells. All endothelial cells showed positive immunoreactivity to the anti-CD34 antibody, and a median distribution of 85 vessels/×200 field was observed. A significant correlation (p < 0.05) was found between the MVD and the International Union Against Cancer (UICC) stage. Statistical analysis showed a significant correlation between VEGF expression and the height of MVD (p < 0.05). Kaplan–Meier analyses revealed that VEGF expression and MVD had a statistically significant correlation with survival after curative resection (p < 0.05). Furthermore, multivariate analysis indicated that VEGF expression is an independent prognostic marker for cancer recurrence within 8 months after curative surgery (p = 0.003). Conclusion In pancreatic adenocarcinoma, the VEGF expression and the height of MVD are closely correlated, and both—rather than UICC stage and TNM classification (tumor size and nodal involvement)—are markers of prognostic relevance after curative resection. Furthermore, VEGF is a predictor of early recurrence after curative resection. The current study indicates that VEGF may promote the distribution of metastases, leading to early cancer recurrence and poor outcome.

Polo-like kinase: a novel marker of proliferation: Correlation with estrogen-receptor expression in human breast cancer

Previous data have shown that the mRNA-expression of the serin/threonine-kinase polo-like kinase (PLK) is closely correlated with the survival of patients suffering from a subset of malignant tumors. PLK-mRNA and protein-expression are restricted to cells in the cell cycle. PLK-mRNA-transcripts are highly abundant in proliferating cells; no gene expression is found in G0-phase cells. Here we investigated the mRNA- and protein-expression of PLK- and estrogen-receptor (ER) in human breast-carcinoma by northern-blotting, RT-PCR and immunohistochemistry. The expression of MIB-I was determined on serial sections. Analysis of the immunohistochemical data revealed a close correlation between the ER and PLK-expression (r = 0.677; p = 0.001, n = 30). No relationship between the mRNA-expression of ER and PLK was found. Furthermore, no correlation for the protein expression of PLK and MIB-I exists. The influence of estrogen (ES) is known to have proliferative potential. The expression of ER correlates with the ES-plasma-level. In addition, the hormone cycle of premenopausal women undergoes rapid vacillations with varying effects on the proliferating tumor cells, e.g., growth induction. Our results therefore show that ER-expression is not only of therapeutic value for the clinician, but it may also be a tool for determining the tumor proliferation index more precisely by integrating the hormone-mediated proliferation stimulus.

Prognostic implications of routine, immunohistochemical, and molecular staging in resectable pancreatic adenocarcinoma.

Cure for ductal adenocarcinoma of the pancreas is restricted to resectable tumors, but survival after surgery is still poor. Despite apparently curative resection, these cancers rapidly recur. Thus, the present pathologic examination should be enriched by sensitive methods to detect minimal residual disease. In a prospective setting we studied the frequency of minimal residual disease after curative resection by routine histopathology, immunohistology, and polymerase chain reaction (PCR) for mutated K-ras. Furthermore, the prognostic implication of detecting of MRD was determined. Prospectively, tumor tissue and corresponding paraaortic lymph nodes were obtained from 78 patients, who underwent surgery for pancreatic head tumors between 1999 and 2001. Sixty-nine of 78 cases were diagnosed for ductal adenocarcinoma (study group), whereas nine cases were diagnosed for benign pancreatic tumors (control group). Paraaortic lymph nodes were examined in step sections by routine histopathology (hematoxylin and eosin) and immunohistology using a pan-cytokeratin antibody. DNA of the primary tumor and corresponding paraaortic lymph nodes were analyzed by PCR-based assays with respect to mutated K-ras in codon 12. The recurrence-free survival and overall survival were correlated with the results of the latter methods. In 3 of 69 patients tumor cells were detected in paraaortic lymph nodes by routine histopathology and in 5 of 69 patients by immunohistology. K-ras mutations were detected in 42 of 69 ductal adenocarcinomas (61%), whereas 12 (17%) were positive in paraaortic lymph nodes. All of the latter patients had recurrence after surgery and a significant poorer survival than those without mutated K-ras. Furthermore, paraaortic lymph nodes diagnosed for K-ras mutation were independent prognostic markers in multivariate analysis. In the control group K-ras mutations were detected in one adenoma of Vaters papilla but not in paraaortic lymph nodes. Tumor cell DNA can be detected more sensitively by the described PCR method than with hematoxylin and eosin or immunohistologic staining, leading to a higher sensitivity for detection of micrometastases. The described PCR method clearly determines subgroups of patients after curative resection with early recurrence and poor survival and could therefore enrich the pathologic examination.

Angiogenesis and cathepsin expression are prognostic factors in pancreatic adenocarcinoma after curative resection

SummaryBackground. Curative resection of pancreatic adenocarcinoma is the only clinical parameter related to a favorable prognosis while other clinicopathological parameters fail. To evaluate whether angiogenesis, vascular endothelial growth factor (VEGF) or certain tumor proteases, e.g., cathepsin B (CTSB) and L (CTSL), are factors of prognostic relevance, we investigated their expression in patients with long- and short-term survival after curative resection (R0) because of pancreatic adenocarcinoma.Methods. Twenty-nine tissue samples from patients with adenocarcinoma of the pancreas were examined. The patients were selected in a long-term survival group with a survival ≥24 mo (n=18) and a short-term survival group of patients, who died within 8 mo after surgery because of their malignancy (n=11). The microvessel quantification was performed immunohistochemically using a monoclonal anti-CD34 antibody. VEGF, CTSB, and CTSL expressions was studied using polyclonal antibodies (PAbs).Results. The median microvessel density (MVD) was 75 (range 39–182). MVD correlated significantly with the survival time after surgery (p=0.0132) but not with clinicopathological parameters. In cancer cells, VEGF was positive in 82.8% and showed significant correlation with the MVD (p=0.0002) and survival time (p=0.0395). Positive immunoreactivity could be obtained for 96.5% for CTSB and 84.2% for CTSL. Expression of both proteases correlated significantly with the survival time after surgery (CTSB p=0.0002, CTSL p=0.0001). Furthermore, CTSB expression correlated with invasion of the perineural space. Thus, a short postoperative survival correlated with a high MVD, and highly expressed VEGF, CTSB, and CTSL. No significant correlation between MVD, VEGF, as well as CTSL and clinicopathological parameters was found. For routinely assessed markers (e.g., TNM-stage, UICC-stage, and so on) no significant correlation with survival time was found in this small group of patients.Conclusion. These findings indicate that the MVD, VEGF, CTSB, and CTSL are prognostic factors after curative resection, whereas other parameters (TNM, UICC, and so on) failed to show prognostic relevance in our group of patients. Furthermore, the correlation between MVD and VEGF underlines the importance of this growth factor for angiogenesis and tumor growth. The correlation between CTSB and perineural invasion demonstrates the involvement of cathepsins in local tumor invasion.

Urokinase plasminogen activator receptor (CD87) expression of tumor-associated macrophages in ductal carcinoma in situ, breast cancer, and resident macrophages of normal breast tissue.

Macrophages concentrate urokinase‐type plasminogen activator (uPA) at the cell surface by expressing urokinase receptors (uPAR) in order to focus the pericellular space plasminogen‐dependent proteolysis important in matrix remodeling and cell movement. This study examines the uPAR levels of tumor‐associated macrophages (TAM) of invasive breast carcinomas, of TAMs from ductal carcinoma in situ (DCIS) and of macrophages derived from normal (non‐tumor) breast tissue. TAMs from invasive breast carcinomas (n = 30), from DCIS (n = 12), and macrophages from normal breast tissue (n = 30) were cultured and immunocytochemically phenotyped by using a panel of antibodies. Urokinase receptor levels were determined by Western blot analysis and in cell‐free supernatants by enzyme‐linked immunosorbent assay. Urokinase receptor cell surface fluorescence intensity was determined by FACS and by confocal laser scan microscopy. Urokinase‐receptor mRNA was detected by in situ hybridization. TAMs of invasive breast carcinomas and of DCIS possess significantly elevated uPAR levels compared with macrophages derived from normal breast tissue. Conclusions: activated macrophages with elevated uPAR levels belong to inflammatory areas in close vicinity of infiltrating and non‐infiltrating (DCIS) tumor cells. Blood monocytes that possess elevated uPAR‐levels may be selectively recruited from the bloodstream to inflammatory sites close to carcinoma cells, and/or breast cancer and precursor lesions may induce elevated uPAR‐levels in TAMs by paracrine interactions. J. Leukoc. Biol. 66: 40–49; 1999.

HER2/neu, p53, Ki67, and hormone receptors do not change during neoadjuvant chemotherapy in breast cancer.

The selection of a systemic breast cancer therapy is based on the expression pattern of immunohistochemical prognostic markers. In our study we sought to determine whether neoadjuvant chemotherapy may alter these expression patterns within the tumors. Our hypothesis was that the expression of the immunohistochemical prognostic markers does not differ between tissue specimens before and after neoadjuvant chemotherapy. We determined the protein expression levels of estrogen receptor, progesterone receptor, Ki67, p53 and HER2/neu in the core biopsy and the resected tumor sample from 25 patients receiving neoadjuvant chemotherapy. As a control group, we analyzed sample pairs from 30 patients who did not receive neoadjuvant chemotherapy. Additionally, we determined the relative HER2/neu gene copy number by FISH and/or real-time PCR. There were no significant differences in the changes in expression patterns from the core biopsy to the treated resected tumor between those who had received neoadjuvant chemotherapy and the control group. We suggest that it is sufficient to analyze the prognostic factors from either the core biopsy prior to chemotherapy or the treated tumor sample instead of investigating both samples. This would markedly reduce the costs.

Modulators of the urokinase-type plasminogen activation system for cancer

Importance of the field: The serine protease urokinase-type plasminogen activator (uPA) and its receptor uPAR as well as two specific inhibitors, the plasminogen activator inhibitor type-1 (PAI-1) and type-2 (PAI-2), are involved in the control of extracellular matrix turnover and tumor growth. Data accumulating over the past 20 years have made increasingly clear that the uPA system has a multifunctional role in neoplastic evolution, affecting cancer cell proliferation, tumor angiogenesis, adhesion and migration. Areas covered in this review: Several therapeutic strategies inhibiting the uPA system have been or are currently being developed for suppression of tumor growth. This review examines the role of the uPA system in tumor progression and assesses the various therapeutic strategies developed to selectively exploit this system. What will the reader gain: We focus on the therapeutic developments of the last 15 years. In addition to antibodies and recombinant uPA- or uPAR-derived proteins, various antagonistic peptides as well as small molecules have been designed and synthesized that inhibit the uPA system, leading to reduced tumor progression. Take home message: The multifunctional potential of the uPA system in cancer has rendered this system an attractive novel target for anticancer therapy. A few novel tumor biology-based therapeutic strategies reported here, opening new ways for patient-optimized and individualized cancer therapy. It may be the right time to evaluate the hypothesis that the uPA system plays a pivotal role in cancer progression and that targeting this system will lead to clinical benefit in cancer patients.

Cutaneous large B-cell lymphoma of the leg masquerading as a chronic venous ulcer

We report on a 74‐year‐old female patient with a primary cutaneous CD20+, diffuse large cell B‐cell lymphoma of the lower leg resembling a chronic non‐healing leg ulcer. There was no evidence of systemic involvement on computed tomography (CT) scans of the chest, abdomen and pelvis; a slightly enlarged lymph node in the right groin showed dermatopathic lymphadenopathy on histology and immunohistochemistry. Involvement of the bone marrow and peripheral blood was ruled out by punch biopsy and fluorescent activated cell sorter (FACS) analysis of the blood, respectively. Therapeutic anti‐CD20 monoclonal antibody rituximab was given at 375 mg m−2 i.v. once weekly for 7 weeks, without adverse effects, resulting in a minor improvement in the centre of the ulcerated tumour. Unfortunately, the response was not maintained, and after 7 weeks of treatment the patient started to develop new tumour lesions at the border of the ulcer. Local radiotherapy was started and combined photon and electron beam irradiation induced complete remission of the B‐cell lymphoma.

Dose-dependent severe cutaneous reactions to imatinib

The protein kinase inhibitor imatinib has been approved as an efficient anticancer drug with common but mild cutaneous toxicities. We here report on two out of four melanoma patients treated with high-dose imatinib presenting with severe and strongly dose-dependent skin eruptions, suggesting a cutaneous reactivity pattern different from allergic hypersensitivity.