Stefan Aebi

The Notch pathway in ovarian carcinomas and adenomas

Elements of the Notch pathway regulate differentiation; we investigated the expression of such elements in epithelial ovarian tumours. A total of 32 ovarian tumour samples (17 adenocarcinomas, three borderline tumours, 12 adenomas), two human ovarian cancer (A2780, OVCAR3), and one ovarian surface (IOSE 144) cell lines were analysed. The expression of Notch pathway elements was assessed by RT–PCR, real-time PCR (Notch 1), and by immunoblots (Notch 1 extracellular domain (EC), HES1). The proliferation and colony formation of A2780 cells were measured after stable transfection with activated Notch 1 (intracellular domain). Jagged 2, Delta-like-1, Manic Fringe, and TSL1 were expressed more frequently in adenocarcinomas whereas Deltex, Mastermind, and Radical Fringe were more frequent in adenomas. Quantitative PCR revealed decreased Notch 1 mRNA in ovarian adenocarcinomas compared with adenomas. The expression of Notch 1-EC protein was similar in benign and malignant tumours. HES1 protein was strongly expressed in 18/19 ovarian cancers and borderline tumours but not in adenomas. Transfecting A2780 cells with active Notch 1-IC resulted in a proliferative and colony formation advantage compared to mock transfected cells. Thus, Notch pathway elements are expressed in ovarian epithelial tumours and some of them are differentially expressed between adenomas and carcinomas. The Notch pathway could be a target for the development of therapies for ovarian cancer.

Assessment of Differences in Patient Populations Selected for or Excluded From Participation in Clinical Phase III Acute Myelogenous Leukemia Trials

PURPOSE To compare patients treated in or outside clinical protocols, using de novo acute myeloid leukemia (AML) as a model disorder. PATIENTS AND METHODS We retrospectively compared the characteristics of all patients with de novo AML diagnosed in the referral area of our university hospital between 1985 and 1994. RESULTS Of a total of 170 AML patients, 45% were included in a phase III trial for the treatment of AML and 55% were treated outside a protocol. Another 45 patients were registered only at diagnosis but were treated elsewhere. Nonstudy patients differed significantly from patients included in clinical trials with respect to age and performance status at clinical presentation, comorbidity, and type of AML. The great majority of patients excluded from trial participation showed distinct exclusion criteria, such as advanced age and severe comorbidity. Study patients were treated significantly more often with curative intent and achieved better response and survival. Patients treated in an equivalent manner but outside a protocol showed no significant difference in survival compared with patients enrolled onto a trial. CONCLUSION Study patients were not representative for the entire population of patients with AML; many patients were excluded from phase III trial participation for failure to meet stringent entry criteria. Therefore, results of phase III studies may not be extrapolated to all AML patients but should only be applied to patients who do not differ in substantial characteristics from the study population.

Dihydropyrimidine dehydrogenase gene variation and severe 5-fluorouracil toxicity: a haplotype assessment

AIMS The importance of polymorphisms in the dihydropyrimidine dehydrogenase gene (DPYD) for the prediction of severe toxicity in 5-fluorouracil (5-FU)-based chemotherapy is still unclear. This study aims to assess the predictive value of DPYD variation with respect to previously described DPYD variants for 5-FU toxicity. It represents the first analysis of the gene at the haplotype level, also capturing potentially important genetic variation located outside the coding regions of DPYD. MATERIALS & METHODS The entire coding sequence and exon-flanking intronic regions of DPYD were sequenced in 111 cancer patients receiving fluoropyrimidine-based chemotherapy. DPYD haplotypes were inferred and their associations with severe 5-FU toxicity were assessed. RESULTS None of the previously described deleterious variants (IVS14+1G>A, c.2846A>T and c.1679T>G) were detected in 24 patients who experienced severe 5-FU toxicity. A potential association was observed between a haplotype containing three novel intronic polymorphisms (IVS5+18G>A, IVS6+139G>A and IVS9-51T>G) and a synonymous mutation (c.1236G>A), which was observed five- out of eight-times in patients with severe adverse effects. CONCLUSION The association of a haplotype containing no nonsynonymous or splice-site polymorphisms indicates that additional important genetic variation may be located in noncoding gene regions. Furthermore, a comparison with other studies suggests that the relative importance of particular DPYD mutations (IVS14+1G>A and c.2846A>T) for predicting severe 5-FU toxicity differs geographically across Europe.

The effect of different chemotherapeutic agents on the enrichment of DNA mismatch repair-deficient tumour cells.

Loss of DNA mismatch repair is a common finding in hereditary non-polyposis colon cancer as well as in many types of sporadic human tumours. We compared the effect of loss of DNA mismatch repair on drug sensitivity as measured by a clonogenic assay with its effect on the ability of the same drug to enrich for mismatch repair-deficient cells in a proliferating tumour cell population. Mixed populations containing 50% DNA mismatch repair-deficient cells constitutively expressing green fluorescent protein and 50% mismatch repair-proficient cells were exposed to different chemotherapeutic agents. 6-Thioguanine, to which DNA mismatch repair-deficient cells are known to be resistant, was included as a control. The results in the cytotoxicity assays and in the enrichment experiments were concordant. Treatment with either carboplatin, cisplatin, doxorubicin, etoposide or 6-thioguanine resulted in enrichment for mismatch repair-deficient cells, and clonogenic assays demonstrated resistance to these agents, which varied from 1.3- to 4.8-fold. Treatment with melphalan, paclitaxel, perfosfamide or tamoxifen failed to enrich for mismatch repair-deficient cells, and no change in sensitivity to these agents was detected in the clonogenic assays. These results identify the topoisomerase II inhibitors etoposide and doxorubicin as additional agents for which loss of DNA mismatch repair causes drug resistance. The concordance of the results from the two assay systems validates the enrichment assay as a rapid and reliable method for screening for the effect of loss of DNA mismatch repair on sensitivity to additional drugs.

Multicycle dose-intensive chemotherapy for women with high-risk primary breast cancer: results of International Breast Cancer Study Group Trial 15-95

PURPOSE To compare adjuvant dose-intensive epirubicin and cyclophosphamide chemotherapy administered with filgrastim and progenitor cell support (DI-EC) with standard-dose anthracycline-based chemotherapy (SD-CT) for patients with early-stage breast cancer and a high risk of relapse, defined as stage II disease with 10 or more positive axillary nodes; or an estrogen receptor-negative or stage III tumor with five or more positive axillary nodes. PATIENTS AND METHODS Three hundred forty-four patients were randomized after surgery to receive seven cycles of SD-CT over 22 weeks, or three cycles of DI-EC (epirubicin 200 mg/m2 plus cyclophosphamide 4 gm/m2 with filgrastim and progenitor cell support) over 6 weeks. All patients were assigned tamoxifen at the completion of chemotherapy. The primary end point was disease-free survival (DFS). RESULTS After a median follow-up of 5.8 years (range, 3 to 8.4 years), 188 DFS events had occurred (DI-EC, 86 events; SD-CT, 102 events). The 5-year DFS was 52% for DI-EC and 43% for SD-CT, with hazard ratio of DI-EC compared with SD-CT of 0.77 (95% CI, 0.58 to 1.02; P = .07). The 5-year overall survival was 70% for DI-EC and 61% for SD-CT, with a hazard ratio of 0.79 (95% CI, 0.56 to 1.11; P = .17). There were eight cases (5%) of anthracycline-induced cardiomyopathy (two fatal) among those who received DI-EC. Women with hormone receptor-positive tumors benefited significantly from DI-EC. CONCLUSION There was a trend in favor of DI-EC with respect to disease-free survival. A larger trial or meta-analysis will be required to reveal the true effect of dose-intensive therapy.

Anastrozole (‘Arimidex’) versus tamoxifen as first-line therapy in postmenopausal women with advanced breast cancer: Results of the double-blind cross-over SAKK trial 21/95 - a sub-study of the TARGET (Tamoxifen or ‘Arimidex’ Randomized Group Efficacy and Tolerability) trial

It is desirable to identify the most effective sequence of endocrine therapies for the treatment of postmenopausal women with advanced, hormone-responsive breast cancer. In a retrospective analysis of two large, randomized, comparative Phase III trials in this patient population, the Tamoxifen or ‘Arimidex’ Randomized Group Efficacy and Tolerability (TARGET) trial and the North American trial, we ascertained that tumors responding to anastrozole as first-line therapy may subsequently respond to tamoxifen as second-line therapy. In a double-blind cross-over trial, the SAKK 21/95 sub-trial (including patients from the Swiss centres in the TARGET trial), we further investigated the clinical impact of anastrozole followed by tamoxifen compared with that of tamoxifen followed by anastrozole. Patients with locally advanced or metastatic breast cancer who had continued on randomized treatment until objective disease progression and were still considered suitable for endocrine therapy, could continue on blinded therapy crossing-over to the alternative treatment. They were assessed for time to progression (TTP) from treatment randomization, TTP after crossing-over treatments, time from randomization to progression after crossing-over treatments and overall survival. Median TTP from randomization for patients receiving first-line treatment with anastrozole (n= 31) and tamoxifen (n= 29) was 11.3 and 8.3 months, respectively, p= 0.75. Median TTP from treatment cross-over was 6.7 months for tamoxifen after progression on anastrozole (n= 19) and 5.7 months for anastrozole after progression on tamoxifen (n= 18), while median time from randomization to second progression was 28.2 and 19.5 months, respectively. Overall survival from randomization for the anastrozole-tamoxifen sequence and the tamoxifen-anastrozole sequence was 69.7 versus 59.3 months, respectively, p= 0.10. The relative risk of death was higher for the tamoxifen followed by anastrozole sequence (1.63; 95% confidence interval [CI] 0.89–2.98). Tamoxifen is an effective second-line therapy after anastrozole. Our data, together with the better tolerability profile of anastrozole compared with tamoxifen, support the use of anastrozole as first-line therapy for advanced breast cancer in postmenopausal women with hormone receptor-positive tumors. Treatment with tamoxifen may still be useful upon subsequent progression.

Bcl‐xl antisense oligonucleotides induce apoptosis and increase sensitivity of pancreatic cancer cells to gemcitabine

Pancreatic cancer is one of the leading causes of cancer‐related death in Western countries. Bcl‐xL is an anti‐apoptotic factor of the Bcl‐2 family, which is overexpressed in pancreatic cancer and its presence correlates with shorter patient survival. In this study, sequence‐specific antisense oligonucleotides targeting the coding region of Bcl‐xL were designed to examine whether apoptosis could be induced and chemosensitivity could be increased in pancreatic cancer cells. Five pancreatic cancer cell lines, Panc‐1, MIA‐PaCa‐2, Capan‐1, ASPC‐1 and T3M4, were treated with Bcl‐xL sense or antisense oligonucleotides and gemcitabine and the cell viability was examined by the SRB method. Apoptosis was determined using DAPI staining. In all examined pancreatic cancer cells, Bcl‐xL expression was reduced after transfection of the antisense oligonucleotides. Cell death analysis using DAPI staining revealed that antisense, but not sense oligonucleotides caused apoptotic cell death. Furthermore, Bcl‐xL antisense oligonucleotides enhanced the cytotoxic effects of gemcitabine in pancreatic cancer cells. Our results indicate that Bcl‐xL antisense oligonucleotides effectively inhibited pancreatic cancer cell growth and caused apoptosis by reducing Bcl‐xL protein levels. Bcl‐xL antisense oligonucleotides also increased the chemosensitivity of pancreatic cancer cells, suggesting that Bcl‐xL antisense therapy might be a potential future approach in this disease.

Expression profiling with RNA from formalin-fixed, paraffin-embedded material

BackgroundMolecular characterization of breast and other cancers by gene expression profiling has corroborated existing classifications and revealed novel subtypes. Most profiling studies are based on fresh frozen (FF) tumor material which is available only for a limited number of samples while thousands of tumor samples exist as formalin-fixed, paraffin-embedded (FFPE) blocks. Unfortunately, RNA derived of FFPE material is fragmented and chemically modified impairing expression measurements by standard procedures. Robust protocols for isolation of RNA from FFPE material suitable for stable and reproducible measurement of gene expression (e.g. by quantitative reverse transcriptase PCR, QPCR) remain a major challenge.ResultsWe present a simple procedure for RNA isolation from FFPE material of diagnostic samples. The RNA is suitable for expression measurement by QPCR when used in combination with an optimized cDNA synthesis protocol and TaqMan assays specific for short amplicons. The FFPE derived RNA was compared to intact RNA isolated from the same tumors. Preliminary scores were computed from genes related to the ER response, HER2 signaling and proliferation. Correlation coefficients between intact and partially fragmented RNA from FFPE material were 0.83 to 0.97.ConclusionWe developed a simple and robust method for isolating RNA from FFPE material. The RNA can be used for gene expression profiling. Expression measurements from several genes can be combined to robust scores representing the hormonal or the proliferation status of the tumor.

Overexpression of the p73 gene is a novel finding in high-risk B-cell chronic lymphocytic leukemia

The p73 protein shares structural and functional similarities with the tumour-suppressor p53, but its role in neoplastic transformation is unknown. Alternative splicing leads to the expression of at least nine p73 C-terminal mRNA splice variants (alpha, beta, gamma, delta, epsilon, zeta, eta, eta1, theta). In this survey, we analyse the expression of p73 by real-time quantitative RT-PCR, its known C-terminal variants with an RT-PCR-Southern technique and by Western blot in samples of 51 patients with B-CLL, normal B lymphocytes from eight individuals, and five haematopoetic cell lines. p73alpha protein expression positively correlated with higher risk B-CLL stages (P = 0.046). Total p73 mRNA expression was higher (P = 0.01) and p73alpha protein more frequently detected (P = 0.008) in B-CLL compared with normal CD19+-B-lymphocytes. p73 C-terminal mRNA variants were expressed both in B-CLL and in normal B-lymphocytes, but their expression was biased since the gamma (P = 0.041), the theta (P < 0.001), and the eta variant (P = 0.033) prevailed in normal B-lymphocytes. In summary, we conclude that the accumulation of p73, the expression pattern of particular p73 variants and its link to progression may play a distinct role in the molecular pathology B-CLL.

Adjuvant Chemotherapy Followed By Goserelin Compared With Either Modality Alone: The Impact on Amenorrhea, Hot Flashes, and Quality of Life in Premenopausal Patients—The International Breast Cancer Study Group Trial VIII

PURPOSE The purpose of this article is to compare quality of life (QOL) and menopausal symptoms among premenopausal patients with lymph node-negative breast cancer receiving chemotherapy, goserelin, or their sequential combination, and to investigate differential effects by age. PATIENTS AND METHODS We evaluated QOL data from 874 pre- and perimenopausal women with lymph node-negative breast cancer who were randomly assigned to receive six courses of classical cyclophosphamide, methotrexate, and fluorouracil (CMF) chemotherapy, ovarian suppression with goserelin for 24 months, or six courses of classical CMF followed by 18 months of goserelin. We report QOL data collected during 3 years after random assignment in patients without disease recurrence. RESULTS Overall, patients receiving goserelin alone showed a marked improvement or less deterioration in QOL measures over the first 6 months than those patients treated with CMF. There were no differences at 3 years after random assignment according to treatment except for hot flashes. As reflected in the hot flashes scores, patients in all three treatment groups experienced induced amenorrhea, but the onset of ovarian function suppression was slightly delayed for patients receiving chemotherapy. Younger patients (< 40 years) who received goserelin alone returned to their premenopausal status at 6 months after the cessation of therapy, while those who received CMF showed marginal changes from their baseline hot flashes scores. CONCLUSION Age-adjusted risk profiles that consider patient-reported outcomes enable patients to adapt to their disease and treatment, such as considering the trade-offs between delayed endocrine symptoms, but higher risk of permanent menopause with chemotherapy, and immediate but reversible endocrine symptoms with goserelin, in younger premenopausal patients.