Werner Rittgen

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.

Prognostic value of ERBB-1, VEGF, cyclin A, FOS, JUN and MYC in patients with squamous cell lung carcinomas

Patients with previously untreated squamous cell lung carcinomas were evaluated to see if combining the expression of molecular and cellular factors with the most important clinical prognostic factors could improve the diagnostic ability to predict prognosis. For this reason, immunohistochemistry was used to examine the squamous cell lung carcinomas from 121 patients for their expression of ERBB-1, vascular endothelial growth factor (VEGF), cyclin A, FOS, JUN and MYC. Median survival was shorter for patients with ERBB-1-, VEGF-, cyclin A-, FOS-, or JUN-positive tumours. For those patients with positive lymph node involvement, the survival times were also shorter in the VEGF-positive, cyclin A-positive and FOS-positive groups. Multivariate analysis independently demonstrated a significant prognostic value for lymph node involvement, VEGF and FOS.

Primary staging and follow-up in melanoma patients – monocenter evaluation of methods, costs and patient survival

In a German cohort of 661 melanoma patients the performance, costs and survival benefits of staging methods (history and physical examination; chest X-ray; ultrasonography of the abdomen; high resolution sonography of the peripheral lymph nodes) were assessed at initial staging and during follow-up of stage I/II+III disease. At initial staging, 74% (23 out of 31) of synchronous metastases were first detected by physical examination followed by sonography of the lymph nodes revealing 16% (5 out of 31). Other imaging methods were less efficient (Chest X-ray: one out of 31; sonography of abdomen: two out of 31). Nearly 24% of all 127 first recurrences and 18% of 73 second recurrences developed in patients not participating in the follow-up programme. In follow-up patients detection of first or second recurrence were attributed to history and physical examination on a routine visit in 47 and 52% recurrences, respectively, and to routine imaging procedures in 21 and 17% of cases, respectively. Lymph node sonography was the most successful technical staging procedure indicating 13% of first relapses, but comprised 24% of total costs of follow-up in stage I/II. Routine imaging comprised nearly 50% of total costs for follow-up in stage I/II and in stage III. The mode of detecting a relapse (‘patient vs. doctor-diagnosed’ or ‘symptomatic vs asymptomatic’) did not significantly influence patients overall survival. Taken together, imaging procedures for routine follow-up in stage I/II and stage III melanoma patients were inefficient and not cost-efficient.

p16INK4a overexpression predicts translational active human papillomavirus infection in tonsillar cancer.

The causal role of human papillomaviruses (HPV) in squamous cell carcinogenesis of tonsillar cancers (TSCC) depends on the activity of the viral oncoproteins E6 and E7, leading to inactivation of the cellular tumor suppressor p53 and the retinoblastoma gene product pRb. Because of the negative feedback mechanisms, the pRb inactivation causes an increase of the inhibitor of the cyclin‐dependent kinases p16INK4a. In 39 TSCC specimens, genotyping based on the amplification of HPV DNA was carried out using PCR by applying HPV type‐specific oligonucleotides. Subsequently, amplicons were hybridised with fluorescence‐labeled complementary probes using the Southern blot technology. For HPV E6/E7 mRNA expression, Northern hybridization and RT‐PCR were performed, and for p16INK4a detection, immunohistochemistry was performed. With 21/39 (53%) HPV‐positives, the detection rate is within the range that can be expected in TSCC. The E6/E7 oncogene mRNA was detectable in 11 cases, 10 of which showed positive signals after p16INK4a staining. Albeit the small study group was investigated, the correlation of the HPV DNA status with the p16INK4a expression was of statistical significance (p = 0.02). Kaplan‐Meier estimations revealed better survival outcome for patients with HPV‐positive tumors with detectable E6/E7 mRNA and p16INK4a overexpression (p = 0.02, median observation time 29 months). As mRNA expression tests are not routinely available in many clinical diagnostic laboratories, and based on the high correlation of p16INK4a staining with HPV E6/E7 mRNA expression, in conclusion we suggest for a deeper exploration for the use of p16INK4a as a surrogate marker with the potential to impact the standard of care of HPV DNA‐positive head and neck carcinomas.

B-RAF and N-RAS Mutations Are Preserved during Short Time In Vitro Propagation and Differentially Impact Prognosis

In melanoma, the RAS/RAF/MEK/ERK signalling pathway is an area of great interest, because it regulates tumor cell proliferation and survival. A varying mutation rate has been reported for B-RAF and N-RAS, which has been largely attributed to the differential source of tumor DNA analyzed, e.g., fixed tumor tissues or in vitro propagated melanoma cells. Notably, this variation also interfered with interpreting the impact of these mutations on the clinical course of the disease. Consequently, we investigated the mutational profile of B-RAF and N-RAS in biopsies and corresponding cell lines from metastatic tumor lesions of 109 melanoma patients (AJCC stage III/IV), and its respective impact on survival. 97 tissue biopsies and 105 biopsy-derived cell lines were screened for B-RAF and N-RAS mutations by PCR single strand conformation polymorphism and DNA sequencing. Mutations were correlated with patient survival data obtained within a median follow-up time of 31 months. B-RAF mutations were detected in 55% tissues and 51% cell lines, N-RAS mutations in 23% tissues and 25% cell lines, respectively. There was strong concordance between the mutational status of tissues and corresponding cell lines, showing a differing status for B-RAF in only 5% and N-RAS in only 6%, respectively. Patients with tumors carrying mutated B-RAF showed an impaired median survival (8.0 versus 11.8 months, p = 0.055, tissues; 7.1 versus 9.3 months, p = 0.068, cell lines), whereas patients with N-RAS-mutated tumors presented with a favorable prognosis (median survival 12.5 versus 7.9 months, p = 0.084, tissues; 15.4 versus 6.8 months, p = 0.0008, cell lines), each in comparison with wildtype gene status. Multivariate analysis qualified N-RAS (p = 0.006) but not B-RAF mutation status as an independent prognostic factor of overall survival. Our findings demonstrate that B-RAF and N-RAS mutations are well preserved during short term in vitro propagation and, most importantly, differentially impact the outcome of melanoma patients.

Altered DNA repair capacity and bleomycin sensitivity as risk markers for non-small cell lung cancer.

DNA repair capacity in human peripheral blood lymphocytes was monitored by the repair rate of bleomycin‐induced DNA damage using an alkaline single‐cell gel electrophoresis assay (comet assay). DNA repair capacity, after 15 min repair time, in lymphocytes of non‐small cell lung cancer patients (n = 160) and controls (n = 180) was 67% and 79.3%, respectively (p < 0.0004). Bleomycin sensitivity defined as the tail moment of bleomycin‐treated peripheral blood lymphocytes, without allowing time for DNA repair, was significantly higher in lung cancer patients than in tumor‐free hospital controls (p < 0.0001). There was no correlation, in either patient or control group, between the bleomycin sensitivity and DNA repair capacity with age or gender. The median values of DNA repair capacity and sensitivity in controls were used as the cut‐off points for calculating odds ratios (OR). After adjustment for age, gender and smoking status, the cases vs. controls had reduced DNA repair capacity (OR = 2.1; 95% confidence limit [CL] 1.1–4.0) and increased bleomycin sensitivity (OR = 4; 95% CL 2.2–7.4). For current smokers, the adjusted risk associated with bleomycin sensitivity was 2.3 (95% CL 1.1–4.9). We conclude that our standard comet assay as a phenotypical repair test has sufficient sensitivity and rapidity allowing application to both native and cryopreserved lymphocytes. Bleomycin sensitivity and DNA repair capacity were found to be 2 independent susceptibility markers for non‐small cell lung cancer, confirming similar investigations with different marker end points. The latter were much more time consuming than the method used in our study. Thus, the comet assay is more suitable for screening large numbers of individuals in epidemiological studies. Validation of this assay in large prospective studies for the identification of subjects at high risk for non‐small cell lung cancer is now warranted.

In vitro Drug Sensitivity Predicts Response and Survival after Individualized Sensitivity-Directed Chemotherapy in Metastatic Melanoma: A Multicenter Phase II Trial of the Dermatologic Cooperative Oncology Group

Purpose:In vitro sensitivity assays are promising tools to predict the individual outcome of different chemotherapy regimens. However, a direct association between in vitro and in vivo chemosensitivity has to be shown by clinical studies. This multicenter phase II trial was aimed to investigate the efficacy of a sensitivity-directed, first-line chemotherapy in metastasized melanoma patients, and to prove an association between in vitro sensitivity and therapy outcome. Patients and Methods: The primary study end point was objective response; secondary end points were safety, overall survival, and progression-free survival. Viable tumor cells obtained from metastatic lesions were tested for chemosensitivity to seven single drugs and five drug combinations using an ATP-based luminescence viability assay. Results: Out of 82 recruited patients (intention-to-treat), 57 received assay-directed chemotherapy and 53 were evaluable for all study end points (per protocol). The drug combinations used were gemcitabine + treosulfan, paclitaxel + cisplatin, paclitaxel + doxorubicin, and gemcitabine + cisplatin. The per protocol population could be divided into 22 (42%) chemosensitive and 31 (58%) chemoresistant patients by an arbitrary chemosensitivity index. Objective response was 36.4% in chemosensitive patients compared with 16.1% in chemoresistant patients (P = 0.114); progression arrest (complete response + partial response + stable disease) was 59.1% versus 22.6% (P = 0.01). Chemosensitive patients showed an increased overall survival of 14.6 months compared with 7.4 months in chemoresistant patients (P = 0.041). Conclusion:In vitro chemosensitivity testing may be worthy of further exploration to see if it could be a useful tool to predict the outcome of melanoma patients treated with a sensitivity-directed chemotherapy. Therefore, these preliminary results will be evaluated by a planned phase III trial using a randomized, standard-regimen controlled setting.

Sensitive detection of rare cancer cells in sputum and peripheral blood samples of patients with lung cancer by preproGRP-specific RT-PCR

RT‐PCR‐based amplification of transcripts expressed in cancer but not in normal non‐neoplastic cells is increasingly used for the sensitive detection of rare disseminated or exfoliated cancer cells to improve cancer staging and early detection protocols. However, these assays are frequently hampered by false‐positive test results due to low‐level transcription of the marker genes in normal cells. To overcome these limitations, target transcripts have to be identified that are tightly suppressed in normal non‐neoplastic tissues, whereas they should be actively transcribed in the respective cancer cells. Here, we tested RT‐PCR assays for 7 neuroendocrine marker transcripts including NCAM, PGP 9.5, gastrin, gastrin receptor, synaptophysin, preprogastrin‐releasing peptide (preproGRP) and GRP‐receptor to detect rare exfoliated tumor cells in peripheral venous blood and sputum samples from patients with lung cancer. Among these preproGRP RT‐PCR was the only assay with which illegitimate transcription in blood or sputum samples from healthy donors or patients with unrelated diseases did not interfere. However, it reproducibly detected up to 10 small‐cell lung cancer cells diluted in either 10 ml blood or 5 ml sputum samples. Single blood and sputum samples were collected directly before diagnostic bronchoscopy from 175 patients suspected to have lung cancer. Twenty‐six of these had small‐cell lung cancer (SCLC). Thereof, 13 patients (50%) tested positive in the blood sample and 5 of 23 patients (22%) tested positive in the sputum sample. Moreover, among 92 patients with non‐small‐cell lung cancer (NSCLC) 25 patients (27%) had disseminated cancer cells in peripheral blood. Amplification of preproGRP transcripts from clinical samples is a sensitive and specific assay to detect disseminated or exfoliated lung cancer cells either in peripheral blood or sputum samples.

Clinical and mechanistic aspects of glucocorticoid-induced chemotherapy resistance in the majority of solid tumors

Background: Glucocorticoids have been used widely in conjunction with cancer therapy due to their ability to induce apoptosis in hematological cells and to prevent nausea and emesis. However, recent data including ours, suggest induction of therapy-resistance by glucocorticoids in solid tumors, although it is unclear whether this happens only in few carcinomas or is a more common cell type specific phenomenon. Material and Methods: We performed an overall statistical analysis of our new and recent data obtained with 157 tumor probes evaluated in vitro, ex vivo and in vivo. The effect of glucocorticoids on apoptosis, viability and cell cycle progression under diverse clinically important questions was examined. Results: New in vivo results demonstrate glucocorticoid-induced chemotherapy resistance in xenografted prostate cancer. In an overall statistical analysis we found glucocorticoid-induced resistance in 89% of 157 analysed tumor samples. Resistance is common for several cytotoxic treatments and for several glucocorticoid-derivatives and due to an inhibition of apoptosis, promotion of viability and cell cycle progression. Resistance occurred at clinically achievable peak plasma levels of patients under anti-emetic glucocorticoid therapy and below, lasted for a long time, after one single dose, but was reversible upon removal of glucocorticoids. Two non-steroidal alternative anti-emetic agents did not counteract anticancer treatment and may be sufficient to replace glucocorticoids in co-treatment of carcinoma patients. Conclusion: These data demonstrate the need for prospective clinical studies as well as for detailed mechanistic studies of GC-induced cell-type specific pro- and anti-apoptotic signaling.

Tumor type M2 pyruvate kinase (TuM2-PK) as a novel plasma tumor marker in melanoma.

Proliferating cells express the pyruvate kinase isoenzyme type M2 (M2‐PK). This enzyme exists as an active tetramer and an inactive dimer. The dimeric form is predominantly found in tumor cells and is therefore termed Tumor M2‐PK (TuM2‐PK). TuM2‐PK molecules are released into the peripheral blood and may hereby function as a marker of tumor load in cancer patients. Our study was aimed to investigate TuM2‐PK as a potential plasma marker in melanoma patients compared to the well‐established serum marker S100β. We measured the concentration of TuM2‐PK in plasma and S100β in corresponding serum samples from 300 melanoma patients and 53 healthy controls using a sandwich ELISA and an immunoluminometric assay, respectively. Plasma concentrations of TuM2‐PK were significantly increased in melanoma patients compared to healthy controls (9.30 U/ml vs. 7.20 U/ml; p = 0.0036) and correlated with tumor load (p < 0.0005) and disease stage (p < 0.0005). Patients with elevated plasma TuM2‐PK (cut‐off = 15 U/ml) presented a reduced overall (p < 0.000005) and progression‐free (p = 0.023) survival. Multivariate analysis revealed plasma TuM2‐PK and serum S100β as independent predictors of overall survival in metastasized patients. Neither plasma TuM2‐PK nor serum S100β showed prognostic relevance for tumor‐free patients. Although the sensitivity and specificity to predict disease progression or death was higher for serum S100β compared to plasma TuM2‐PK, the combination of both markers improved the estimation of prognosis compared to that of serum S100β alone.