Glycogen synthase 1 targeting reveals a metabolic vulnerability in triple-negative breast cancer.

BACKGROUND: Hypoxia-induced glycogen turnover is implicated in cancer proliferation and therapy resistance. Triple-negative breast cancers (TNBCs), characterized by a hypoxic tumor microenvironment, respond poorly to therapy. We studied the expression of glycogen synthase 1 (GYS1), the key regulator of glycogenesis, and other glycogen-related enzymes in primary tumors of patients with breast cancer and evaluated the impact of GYS1 downregulation in preclinical models. METHODS: mRNA expression of GYS1 and other glycogen-related enzymes in primary breast tumors and the correlation with patient survival were studied in the METABRIC dataset (n = 1904). Immunohistochemical staining of GYS1 and glycogen was performed on a tissue microarray of primary breast cancers (n = 337). In four breast cancer cell lines and a mouse xenograft model of triple-negative breast cancer, GYS1 was downregulated using small-interfering or stably expressed short-hairpin RNAs to study the effect of downregulation on breast cancer cell proliferation, glycogen content and sensitivity to various metabolically targeted drugs. RESULTS: High GYS1 mRNA expression was associated with poor patient overall survival (HR 1.20, P = 0.009), especially in the TNBC subgroup (HR 1.52, P = 0.014). Immunohistochemical GYS1 expression in primary breast tumors was highest in TNBCs (median H-score 80, IQR 53-121) and other Ki67-high tumors (median H-score 85, IQR 57-124) (P < 0.0001). Knockdown of GYS1 impaired proliferation of breast cancer cells, depleted glycogen stores and delayed growth of MDA-MB-231 xenografts. Knockdown of GYS1 made breast cancer cells more vulnerable to inhibition of mitochondrial proteostasis. CONCLUSIONS: Our findings highlight GYS1 as potential therapeutic target in breast cancer, especially in TNBC and other highly proliferative subsets.

Distress, problems, referral wish, and supportive health care use in breast cancer survivors beyond the first year after chemotherapy completion.

PURPOSE: We examined distress levels, problems, referral wish, and supportive health care use in a cross-sectional group of breast cancer survivors at two-time points with a 1-year time interval. Also, factors related to continuing elevated distress were explored. METHODS: Breast cancer survivors, 1-5 years after chemotherapy completion, filled in the Dutch Distress Thermometer/Problem List (DT/PL) and questions on background characteristics at study inclusion (T1). DT/PL responses and health care use were discussed during semi-structured interviews. One year later, re-assessment took place (T2). The data were analyzed by descriptive and univariate analyses. Continuing elevated distress was defined as a DT score ≥ 5 at T1 and T2. RESULTS: Seventy-three survivors completed all questionnaires (response = 84.6%). Eighteen (25%) experienced continuing elevated distress. Fatigue (T1 N = 48 (66%); T2 N = 41 (56%)) and lack of physical fitness (T1 N = 44 (60%); T2 N = 36 (49%)) were most often reported. Time since diagnosis, health care use, and practical, social, emotional and physical problems were significantly associated with continuing elevated distress. Between diagnosis and T1, N = 49(67%) used supportive healthcare services, mostly a psychologist and/or a physical/lymphedema therapist, and between T1 and T2, 39 (53%) did. At T1, 8 (11%) expressed a referral wish and at T2, 11 (16%) did. CONCLUSIONS: Screening and management of distress, problems, and referral wish are important, even years after chemotherapy completion as a substantial proportion of breast cancer survivors continue to report elevated distress and problems. Special attention should be paid to survivors reporting physical problems, especially fatigue and lack of physical fitness, since these problems are most strongly related to continuing elevated distress.

Enhanced pulmonary uptake on 18F-FES-PET/CT scans after irradiation of the thoracic area: related to fibrosis?

RATIONALE: The use of 16α-[18F]fluoro-17ß-estradiol (FES) positron emission tomography (PET) in clinical dilemmas and for therapy decision-making in lesions expressing estrogen receptors is growing. However, on a considerable number of FES PET scans, previously performed in a research and clinical setting in our institution, FES uptake was noticed in the lungs without an oncologic substrate. We hypothesized that this uptake was related to pulmonary fibrosis as a result of radiation therapy. This descriptive study therefore aimed to investigate whether radiation therapy in the thoracic area is possibly related to enhanced pulmonary, non-tumor FES uptake. METHODS: All FES-PET/CT scans performed in our institution from 2008 to 2017 were retrospectively analyzed. Scans from patients who had received irradiation in the thoracic area prior to the scan were compared to scans of patients who had never received irradiation in the thoracic area. The primary outcome was the presence of enhanced non-tumor FES uptake in the lungs, defined as visually increased FES uptake in the absence of an oncologic substrate on the concordant (contrast-enhanced) CT scan. All CT scans were evaluated for the presence of fibrosis or oncologic substrates. RESULTS: A total of 108 scans were analyzed: 70 scans of patients with previous irradiation in the thoracic area and 38 of patients without. Enhanced non-tumor FES uptake in the lungs was observed in 39/70 irradiated patients (56%), versus in 9/38 (24%) of non-irradiated patients. Fibrosis was present in 37 of the 48 patients with enhanced non-tumor FES uptake (77%), versus in 15 out of 60 (25%) patients without enhanced non-tumor uptake, irrespective of radiotherapy (p < 0.001). CONCLUSION: After irradiation of the thorax, enhanced non-tumor uptake on FES-PET can be observed in the radiation field in a significant proportion of patients. This seems to be related to fibrosis. When observing enhanced FES uptake in the lungs, this should not be interpreted as metastases. Information on recent radiation therapy or history of pulmonary fibrosis should therefore be taken into consideration.

89Zr-trastuzumab PET supports clinical decision making in breast cancer patients, when HER2 status cannot be determined by standard work up.

BACKGROUND: Up-to-date information on human epidermal growth factor receptor 2 (HER2) status in breast cancer (BC) is important, as expression can vary during the course of the disease, necessitating anti-HER2 therapy adjustments. Repeat biopsies, however, are not always possible. In this feasibility trial we assessed whether 89Zr-trastuzumab PET could support diagnostic understanding and aid clinical decision making, when HER2 status could not be determined by standard work up. Additionally, HER2 status on circulating tumour cells (CTCs) was assessed. PATIENTS AND METHODS: 89Zr-trastuzumab PET was performed in patients if disease HER2 status remained unclear after standard work up (bone scan, 18F-FDG PET, CT and if feasible a biopsy). PET result and central pathologic revision of available tumour biopsies were reported to the referring physician. CTC HER2 status prior to PET was evaluated afterwards and therefore not reported. Diagnostic understanding and treatment decision questionnaires were completed by the referring physicians before, directly after and ≥ 3 months after 89Zr-trastuzumab PET. RESULTS: Twenty patients were enrolled: 8 with two primary cancers (HER2-positive and HER2-negative BC or BC and non-BC), 7 with metastases inaccessible for biopsy, 4 with prior HER2-positive and -negative metastases and 1 with primary BC with equivocal HER2 status. 89Zr-trastuzumab PET was positive in 12 patients, negative in 7 and equivocal in 1 patient. In 15/20 patients, 89Zr-trastuzumab PET supported treatment decision. The scan altered treatment of 8 patients, increased physicians' confidence without affecting treatment in 10, and improved physicians' disease understanding in 18 patients. In 10/20 patients CTCs were detected; 6/10 showed HER2 expression. CTC HER2 status was not correlated to 89Zr-trastuzumab PET result or treatment decision. CONCLUSION: 89Zr-trastuzumab PET supports clinical decision making when HER2 status cannot be determined by standard work up. The impact of CTC HER2 status needs to be further explored.

Axillary staging for breast cancer during pregnancy: feasibility and safety of sentinel lymph node biopsy.

BACKGROUND: Safety of sentinel lymph node (SLN) biopsy for breast cancer during pregnancy is insufficiently explored. We investigated efficacy and local recurrence rate in a large series of pregnant patients. PATIENTS AND METHODS: Women diagnosed with breast cancer who underwent SLN biopsy during pregnancy were identified from the International Network on Cancer, Infertility and Pregnancy, the German Breast Group, and the Cancer and Pregnancy Registry. Chart review was performed to record technique and outcome of SLN biopsy, locoregional and distant recurrence, and survival. RESULTS: We identified 145 women with clinically N0 disease who underwent SLN during pregnancy. The SLN detection techniques were as follows: 99mTc-labeled albumin nanocolloid only (n = 96; 66.2%), blue dye only (n = 14; 9.7%), combined technique (n = 15; 10.3%), or unknown (n = 20; 13.8%). Mapping was unsuccessful in one patient (0.7%) and she underwent an axillary lymph node dissection (ALND). Mean number of SLNs was 3.2 (interquartile range 1-3; missing n = 15). Positive SLNs were found in 43 (29.7%) patients and 34 subsequently underwent ALND. After a median follow-up of 48 months (range 1-177), 123 (84.8%) patients were alive and free of disease. Eleven patients experienced a locoregional relapse, including 1 isolated ipsilateral axillary recurrence (0.7%). Eleven (7.6%) patients developed distant metastases, of whom 9 (6.2%) died of breast cancer. No neonatal adverse events related to SLN procedure during pregnancy were reported. CONCLUSIONS: SLN biopsy during pregnancy has a comparably low axillary recurrence rate as in nonpregnant women. Therefore, this method can be considered during pregnancy instead of standard ALND for early-stage, clinically node-negative breast cancer.

Performance of BRCA1/2 mutation prediction models in male breast cancer patients.

To establish whether existing mutation prediction models can identify which male breast cancer (MBC) patients should be offered BRCA1 and BRCA2 diagnostic DNA screening, we compared the performance of BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm), BRCAPRO (BRCA probability) and the Myriad prevalence table ("Myriad"). These models were evaluated using the family data of 307 Dutch MBC probands tested for BRCA1/2, 58 (19%) of whom were carriers. We compared the numbers of observed vs predicted carriers and assessed the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) for each model. BOADICEA predicted the total number of BRCA1/2 mutation carriers quite accurately (observed/predicted ratio: 0.94). When a cut-off of 10% and 20% prior probability was used, BRCAPRO showed a non-significant better performance (observed/predicted ratio BOADICEA: 0.81, 95% confidence interval [CI]: [0.60-1.09] and 0.79, 95% CI: [0.57-1.09], vs. BRCAPRO: 1.02, 95% CI: [0.75-1.38] and 0.94, 95% CI: [0.68-1.31], respectively). Myriad underestimated the number of carriers in up to 69% of the cases. BRCAPRO showed a non-significant, higher AUC than BOADICEA (0.798 vs 0.776). Myriad showed a significantly lower AUC (0.671). BRCAPRO and BOADICEA can efficiently identify MBC patients as BRCA1/2 mutation carriers. Besides their general applicability, these tools will be of particular value in countries with limited healthcare resources.

Molecular imaging as a tool to investigate heterogeneity of advanced HER2-positive breast cancer and to predict patient outcome under trastuzumab emtansine (T-DM1): the ZEPHIR trial.

BACKGROUND: Only human epidermal growth factor receptor (HER)2 status determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) has been validated to predict efficacy of HER2-targeting antibody-drug-conjugate trastuzumab emtansine (T-DM1). We propose molecular imaging to explore intra-/interpatient heterogeneity in HER2 mapping of metastatic disease and to identify patients unlikely to benefit from T-DM1. PATIENTS AND METHODS: HER2-positive mBC patients with IHC3+ or FISH ≥ 2.2 scheduled for T-DM1 underwent a pretreatment HER2-positron emission tomography (PET)/computed tomography (CT) with (89)Zr-trastuzumab. [(18)F]2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT was performed at baseline and before T-DM1 cycle 2. Patients were grouped into four HER2-PET/CT patterns according to the proportion of FDG-avid tumor load showing relevant (89)Zr-trastuzumab uptake (>blood pool activity): patterns A and B were considered positive (>50% or all of the tumor load 'positive'); patterns C and D were considered negative (>50% or all of the tumor load 'negative'). Early FDG-PET/CT was defined as nonresponding when >50% of the tumor load showed no significant reduction of FDG uptake (<15%). Negative (NPV) and positive predictive values (PPV) of HER2-PET/CT, early FDG response and their combination were assessed to predict morphological response (RECIST 1.1) after three T-DM1 cycles and time-to-treatment failure (TTF). RESULTS: In the 56 patients analyzed, 29% had negative HER2-PET/CT while intrapatient heterogeneity (patterns B and C) was found in 46% of patients. Compared with RECIST1.1, respective NPV/PPV for HER2-PET/CT were 88%/72% and 83%/96% for early FDG-PET/CT. Combining HER2-PET/CT and FDG-PET/CT accurately predicted morphological response (PPV and NPV: 100%) and discriminated patients with a median TTF of only 2.8 months [n = 12, 95% confidence interval (CI) 1.4-7.6] from those with a TTF of 15 months (n = 25, 95% CI 9.7-not calculable). CONCLUSIONS: Pretreatment imaging of HER2 targeting, combined with early metabolic response assessment holds great promise for improving the understanding of tumor heterogeneity in mBC and for selecting patients who will/will not benefit from T-DM1. CLINICALTRIALSGOV IDENTIFIER: NCT01565200.

Targeting breast cancer through its microenvironment: current status of preclinical and clinical research in finding relevant targets.

It is increasingly evident that not only breast cancer cells, but also the tissue embedding these cells: the tumor microenvironment, plays an important role in tumor progression, metastasis formation and treatment sensitivity. This review focuses on the current knowledge of processes by which the microenvironment affects breast cancer, including formation of the metastatic niche, metabolic stimulation, stimulation of tumor cell migration, immune modulation, angiogenesis and matrix remodeling. The number of drugs targeting key factors in these processes is expanding, and the available clinical data is increasing. Therefore current strategies for intervention and prediction of treatment response are outlined. At present, targeting the formation of the metastatic niche and metabolic stimulation by the breast cancer microenvironment, are already showing clinical efficacy. Intervening in the stimulation of tumor cell migration and immune modulation by the microenvironment upcoming fields of great research interest. In contrast, targeting microenvironmental angiogenesis or matrix remodeling appears to be of limited clinical relevance in breast cancer treatment so far. Further research is warranted to optimize intervention strategies and develop predictive tests for the relevance of targeting involved factors within the microenvironment in order to optimally personalize breast cancer treatment.

Impact of primary local treatment on the development of distant metastases or death through locoregional recurrence in young breast cancer patients.

In this study, we tested the hypothesis whether breast conserving therapy (BCT) compared with mastectomy is associated with a negative outcome in terms of distant metastases or death (DMD) and investigated the relation between locoregional recurrence (LRR) and DMD in young breast cancer (BC) patients. This study included a consecutive series of 536 patients ≤40 years of age at diagnosis with pathological T1N0-3M0 BC, treated between 1989 and 2005. A multistate survival model was used to evaluate the influences of local treatment and LRR on DMD, adjusted for potential prognostic factors. Patients were treated with mastectomy (N = 213) or BCT (N = 323). Median age at diagnosis was 36.3 years, with a median follow-up of 9.0 years. The 10-year actuarial cumulative incidence of DMD was 30.6 % after mastectomy and 26.3 % after BCT (P = 0.04). In total, 81 (15 %) LRRs were observed. After BCT, patients had a threefold higher risk of LRR than after mastectomy (HR 2.9; 95 % CI 1.6-5.3). Patients with LRR had a higher risk of DMD compared with patients without LRR (HR 5.5; 95 % CI 2.1-14.5). However, BCT was not negatively associated with DMD-after-LRR (HR 0.47; 95 % CI 0.2-1.1, BCT vs mastectomy). In conclusion, although LRR significantly affected DMD, the increased risk of LRR after BCT compared with mastectomy did not lead to a worse DMD outcome in BC patients ≤40 years of age.

Lapatinib: clinical benefit in patients with HER 2-positive advanced breast cancer.

BACKGROUND: Lapatinib, a tyrosine kinase inhibitor of human epidermal growth factor receptor 2 (HER2), has shown activity in combination with capecitabine in patients with HER2-positive advanced breast cancer progressive on standard treatment regimens. We present results on preapproval drug access for this combination in such patients occurring in the general oncology practice in the Netherlands. METHODS: Patients with HER2-positive advanced breast cancer progressive on schedules containing anthracyclines, taxanes, and trastuzumab were eligible. Brain metastases were allowed if stable. Lapatinib 1250 mg÷day was given continuously in combination with capecitabine 1000 mg÷m2 twice daily for two weeks in a three-week cycle. Efficacy was assessed by use of response evaluation criteria in solid tumours version 1.0. Progression-free survival (PFS) and overall survival (OS) were calculated. RESULTS: Eighty-three patients were enrolled from January 2007 until July 2008. The combination was generally well tolerated and the most common drug-related serious adverse events were nausea and÷or vomiting (5%) and diarrhoea (2%). Seventy-eight patients were evaluable for response. Clinical benefit (response or stable disease for at least 12 weeks) was observed in 50 patients (64%) of whom 15 had a partial response and 35 stable disease. The median PFS and OS were 17 weeks (95% CI: 13 to 21) and 39 weeks (95% CI: 24 to 54), respectively. For OS, higher Eastern Cooperative Oncology Group (ECOG) status (p=0.016), brain metastases at study entry (p=0.010) and higher number of metastatic sites (p=0.012) were significantly negative predictive factors. CONCLUSION: In a patient population with heavily pretreated HER2-positive advanced breast cancer lapatinib plus capecitabine was well tolerated and offered clinical benefit.

Biodistribution of 89Zr-trastuzumab and PET imaging of HER2-positive lesions in patients with metastatic breast cancer.

We performed a feasibility study to determine the optimal dosage and time of administration of the monoclonal antibody zirconium-89 ((89)Zr)-trastuzumab to enable positron emission tomography (PET) imaging of human epidermal growth factor receptor 2 (HER2)-positive lesions. Fourteen patients with HER2-positive metastatic breast cancer received 37 MBq of (89)Zr-trastuzumab at one of three doses (10 or 50 mg for those who were trastuzumab-naive and 10 mg for those who were already on trastuzumab treatment). The patients underwent at least two PET scans between days 2 and 5. The results of the study showed that the best time for assessment of (89)Zr-trastuzumab uptake by tumors was 4-5 days after the injection. For optimal PET-scan results, trastuzumab-naive patients required a 50 mg dose of (89)Zr-trastuzumab, and patients already on trastuzumab treatment required a 10 mg dose. The accumulation of (89)Zr-trastuzumab in lesions allowed PET imaging of most of the known lesions and some that had been undetected earlier. The relative uptake values (RUVs) (mean +/- SEM) were 12.8 +/- 5.8, 4.1 +/- 1.6, and 3.5 +/- 4.2 in liver, bone, and brain lesions, respectively, and 5.9 +/- 2.4, 2.8 +/- 0.7, 4.0 +/- 0.7, and 0.20 +/- 0.1 in normal liver, spleen, kidneys, and brain tissue, respectively. PET scanning after administration of (89)Zr-trastuzumab at appropriate doses allows visualization and quantification of uptake in HER2-positive lesions in patients with metastatic breast cancer.

Molecular imaging of breast cancer.

Molecular imaging of breast cancer can potentially be used for breast cancer screening, staging, restaging, response evaluation and guiding therapies. Techniques for molecular breast cancer imaging include magnetic resonance imaging (MRI), optical imaging, and radionuclide imaging with positron emission tomography (PET) or single photon emission computed tomography (SPECT). This review focuses on PET and SPECT imaging which can provide sensitive serial non invasive information of tumor characteristics. Most clinical data are gathered on the visualization of general processes such as glucose metabolism with the PET-tracer [(18)F]fluorodeoxyglucose (FDG) and DNA synthesis with [18F]fluoro-L-thymidine (FLT). Increasingly more breast cancer specific targets are imaged such as the estrogen receptor (ER), growth factors and growth factor receptors. Imaging of the ER with the PET tracer 16-alpha-[(18)F]fluoro-17-beta-estradiol (FES) has shown a good correlation between FES tumor uptake and ER density. (111)In-trastuzumab SPECT to image the human epidermal growth factor receptor 2 (HER2) showed that in most patients with metastatic HER2 overexpressing disease more lesions were detected than with conventional staging procedures. The PET tracer (89)Zr-trastuzumab showed excellent, quantifiable, and specific tumor uptake. (111)In-bevacizumab for SPECT and (89)Zr-bevacizumab for PET-imaging have been developed for vascular endothelial growth factor (VEGF) imaging as an angiogenic marker. Lastly, tracers for the receptors EGFR, IGF-1R, PDGF-betaR and the ligand TGFbeta are under development. Although molecular imaging of breast cancer is still not commonly used in daily clinical practice, its application portfolio is expanding rapidly.

An in vitro model for purging of tumour cells from ovarian tissue.

BACKGROUND: Cryopreservation and autografting of ovarian tissue may preserve fertility after cancer treatment, but could be hampered by tumour cell contamination. Epithelial tumour cell lysis can be obtained with cytotoxic T cell retargeting through the bispecific antibody BIS-1, with combined affinity for the T-cell receptor and epithelial glycoprotein-2 (EGP-2). Our aim was to study the concept of tumour cell purging in the setting of a suspension of ovarian tissue. METHODS: Human ovarian tissue was brought into suspension by mechanical and enzymatic treatment. Cells of the MCF-7 breast cancer cell line and activated human lymphocytes were co- incubated for 4 h with or without BIS-1 and with or without ovarian suspension. After incubation, MCF-7 cell death and cell growth were evaluated by fluorescent cell detection and MTT assay, respectively. Ovarian tissue morphology was evaluated immunohistochemically. RESULTS: MCF-7 cell death and cell growth inhibition increased with increasing ratios of lymphocytes to MCF-7 cells. BIS-1 addition gave further augmentation, with a maximum depletion of growing MCF-7 cells of 89% (SD 11%) versus without BIS-1, 23% (SD 15%; P < 0.001). Follicles remained morphologically intact. CONCLUSIONS: Purging of added epithelial tumour cells from ovarian tissue with BIS-1 is possible in vitro. Morphologically, follicles remain intact after this procedure. This method may contribute to safer replacement of ovarian tissue in female cancer survivors.

Tributyrin enhances the cytotoxic activity of interleukin-2/interleukin-12 stimulated human natural killer cells against LS 174T colon cancer cells in vitro.

Tributyrin has been shown to be cytostatic to tumor cells by inducing differentiation and apoptosis. On the other hand, immunological NK cells can kill tumor cells, particularly when stimulated with interleukin-2 (IL-2) and/or interleukin-12(IL-12). However, little is known about whether and how both antitumor mechanisms act together, although in vivo such an interaction must exist. Here we demonstrate in vitro, that pretreatment of human LS 174T colon cancer cells with nontoxic concentrations of tributyrin augments the sensitivity to spontaneous NK cell activity two-fold. However, when NK cells have been activated with an optimized combination of IL-2 and IL-12, the immunocytotoxicity increases up to five-fold (from 14% to 70%), versus a 3.8-fold increase against untreated cancer cells. These effects are accompanied by increased IFN-gamma secretion and decreased TGF-beta1 secretion. Tributyrin is found to be a potent inducer of ICAM-1, LFA-3 and Fas on target cells corresponding to an increase of the FasL expression by IL-2/IL-12 on the effector cells. Our data suggest a synergistic link between induction of tumor cell differentiation and immunological defense mechanisms that may provide a rational basis for the improvement of clinical protocols, especially for colon cancer.

Telomere length in breast cancer patients before and after chemotherapy with or without stem cell transplantation.

High-dose chemotherapy and peripheral blood stem cell transplantation (PBSCT) may accelerate telomere length loss in haematopoietic stem cells. As data including pre-and post-treatment samples are lacking, we studied leukocyte telomere length and telomerase activity before and after treatment in breast cancer patients randomized to receive 5 adjuvant courses FEC (5-FU, epirubicin and cyclophosphamide) (n = 17), or 4 x FEC followed by high-dose cyclophosphamide, thiotepa, carboplatin and autologous PBSCT (n = 16). Haemoglobin, MCV, leukocyte-and platelet numbers were assessed prior to (t(0)), 5 months after (t(1)) and 9 months after chemotherapy (t(2)); these parameters were decreased at t(1)and t(2)compared to t(0)(high-dose: all parameters; standard-dose: leukocytes and platelets), and all parameters were lower after high-dose than standard-dose treatment at t(1). Paired individual leukocyte samples of t(0)and t(1)showed telomere length change (determined by telomere restricted fragment (TRF) assay) ranging from +0.8 to -2.2 kb, with a decreased TRF length in 9 patients of both groups. Telomerase activity (determined by TRAP assay) was below detection limit in leukocyte samples of t(0)and t(1). Thus, standard-and high-dose chemotherapy negatively affect haematological reconstitution in this setting. In individual patients, telomere length can be remarkably changed following haematological proliferative stress after treatment.

Purging of epithelial tumor cells from peripheral blood stem cells by means of the bispecific antibody BIS-1.

Peripheral blood stem cell (PBSC) support in breast cancer patients allows high-dose chemotherapy, but tumor cell contamination of the PBSCs is a potential source of relapse. Specific carcinoma cell killing can be obtained by retargeting activated T cells with bispecific antibody BIS-1, directed against epithelial glycoprotein-2 and CD3. To purge epithelial tumor cells from the PBSCs of breast cancer patients, activation of T cells in PBSCs and T-cell retargeting by BIS-1 was studied. PBSCs, obtained by leukapheresis after chemotherapy and recombinant human granulocyte colony-stimulating factor, were cultured in the presence of PBS, interleukin-2, OKT3, or interleukin-2/OKT3 for induction of T-cell activation. Subsequently, lysis of epithelial tumor cell lines by activated T cells of PBSCs in the presence or absence of BIS-1 was assessed with the 51Cr-release assay or immunocytochemical staining. The effect on PBSC hematopoietic colony formation (HCF) was evaluated by the granulocyte macrophage colony-stimulating units assay. Prior to activation, PBSCs from breast cancer patients contained higher levels of CD8+ T cells than peripheral blood from healthy volunteers (P < 0.05). The potential of PBSCs to sustain tumor cell lysis was increased after all prior activations and was further enhanced by BIS-1. Maximal BIS-1 effect was observed after OKT3 activation of PBSCs for 72 h (P < 0.0005), inducing a >3 log depletion of tumor cells. HCF was not affected by prior OKT3 activation and/or BIS-1. In conclusion, specific tumor cell lysis by PBSCs can be obtained in vitro by OKT3 activation and BIS-1 retargeting of T cells, without affecting HCF. At present, studies are evaluating this format for future clinical application.

Prevention of febrile leucopenia after chemotherapy in high-risk breast cancer patients: no significant difference between granulocyte-colony stimulating growth factor or ciprofloxacin plus amphotericin B.

In a prospective randomized trial, 40 stage IV breast cancer patients undergoing intermediate high-dose chemotherapy (cyclophosphamide, 5-fluorouracil plus epirubicin or methotrexate), received either recombinant human G-CSF (rhG-CSF, group I) or ciprofloxacin and amphotericin B (CAB, group II) for prevention of febrile leucopenia (FL). In group I, seven of 18 patients developed FL (after 10/108 courses); in group II, seven of 22 patients (7/98 courses) (P = NS). Median hospitalization duration and costs were not different. RhG-CSF was 6.6 times more expensive per course than CAB. In conclusion, prophylactic CAB has similar efficacy to rhG-CSF in this setting, and is more cost-effective.

[Tropical pyomyositis]. / Tropisk pyomyositt.

Tropical pyomyositis is rarely observed among permanent residents of temperate or cold climates and is, to our knowledge, not described among Norwegians. It is a clinical entity comprising general symptoms of infection and abscesses in skeletal muscles. We present one case of tropical pyomyositis acquired in the Dominican Republic. The patient, a female, had an insidious progression of the disease with fever, chills, and general malaise. On admission she had also developed multiple abscesses affecting muscles of the extremities. She required surgical drainage in addition to antibiotics. Cultures from purulent material revealed Staphylococcus aureus.