B-MYB-p53-related relevant regulator for the progression of clear cell renal cell carcinoma.

PURPOSE: To investigate the mRNA expression of B-MYB and MDM2 together with their p53 relatedness in clear cell renal cell carcinoma (ccRCC). METHODS: Genes were screened for their mRNA expression from 529 patients in a publicly available ccRCC cohort (TCGA). A cohort of 101 patients with ccRCC served as validation by qRT-PCR mRNA tissue expression analysis. RESULTS: Expression: B-MYB expression was significantly higher in high-grade tumours (p < 0.0001 and p = 0.048) and in advanced stages (p = 0.005 and p = 0.037) in both cohorts. Correlation: p53-B-MYB as well as MDM2-B-MYB showed significant correlations in local and low-grade ccRCCs, but not in high grade tumours or advanced stages (r < 0.3 and/or p > 0.05). Survival: Multivariable Cox regression of the TCGA cohort revealed B-MYB upregulation and low MDM2 expression as predictors for an impaired overall survival (OS) (HR 1.97; p = 0.0003; HR 2.94, p < 0.0001) and progression-free survival (PFS) (HR 2.86; p = 0.0005; HR 1.58, p = 0.046). In the validation cohort, the results were confirmed for OS by univariable, but not multivariable regression: high B-MYB expression (HR = 3.05, p = 0.035) and low MDM2 expression (HR 3.81, p value 0.036). CONCLUSION: In ccRCC patients with high-grade tumours and advanced stages, high B-MYB expression is common and is associated with poorer OS and PFS. These patients show a loss of their physiological B-MYB-p53 network correlation, suggesting an additional, alternative regulatory, oncogenic mechanism. Assuming further characterization of its signalling pathways, B-MYB could be a potential therapy target for ccRCC.

Clinical relevance of gene expression in localized and metastatic prostate cancer exemplified by FABP5.

PURPOSE: Fatty acid-binding protein 5 (FABP5), a transport protein for lipophilic molecules, has been proposed as protein marker in prostate cancer (PCa). The role of FABP5 gene expression is merely unknown. METHODS: In two cohorts of PCa patients who underwent radical prostatectomy (n = 40 and n = 57) and one cohort of patients treated with palliative transurethral resection of the prostate (pTUR-P; n = 50) FABP5 mRNA expression was analyzed with qRT-PCR. Expression was correlated with clinical parameters. BPH tissue samples served as control. To independently validate findings on FABP5 expression, three microarray and sequencing datasets were reanalyzed (MSKCC 2010 n = 216; TCGA 2015 n = 333; mCRPC, Nature Medicine 2016 n = 114). FABP5 expression was correlated with ERG-fusion status, TCGA subtypes, cancer driver mutations and the expression of druggable downstream pathway components. RESULTS: FABP5 was overexpressed in PCa compared to BPH in the cohorts analyzed by qRT-PCR (radical prostatectomy p = 0.003, p = 0.010; pTUR-P p = 0.002). FABP5 expression was independent of T stage, Gleason Score, nodal status and PSA level. FABP5 overexpression was associated with the absence of TMPRSS2:ERG fusion (p < 0.001 in TCGA and MSKCC). Correlation with TCGA subtypes revealed FABP5 overexpression to be associated with SPOP and FOXA1 mutations. FABP5 was positively correlated with potential drug targets located downstream of FABP5 in the PPAR-signaling pathway. CONCLUSION: FABP5 overexpression is frequent in PCa, but seems to be restricted to TMPRESS2:ERG fusion-negative tumors and is associated with SPOP and FOXA1 mutations. FABP5 overexpression appears to be indicative for increased activity in PPAR signaling, which is potentially druggable.

Radical cystectomy under continuous antiplatelet therapy with acetylsalicylic acid.

INTRODUCTION: Aim of this study was to analyse the perioperative outcome of patients undergoing radical cystectomy under continuous antiplatelet therapy with acetylsalicylic acid. MATERIALS AND METHODS: Using prospectively maintained databases of two departments of urology, we identified 461 consecutive patients who underwent radical cystectomy for bladder cancer (2011-2017). Patients were divided into three groups: 1) on-going antiplatelet therapy with acetylsalicylic acid (n = 50), 2) discontinuing antiplatelet therapy (n = 65) and 3) no antiplatelet therapy (n = 346). Perioperative outcome was compared between the three groups using ANOVA, likelihood ratio or Kruskal Wallis test with post-hoc testing. Uni- and multivariate analyses were performed to identify predictor for perioperative complications and transfusion. RESULTS: Group 1 showed an average estimated blood loss of 732 ±â€¯424, group 2 752 ±â€¯488 and group 3 810 ±â€¯544 ml (p = 0.51). There was no significant difference in transfusion rate (44% in group 1, 45% and 39% in groups 2 and 3, p = 0.63). Severe complications occurred in 26%, 15% and 15% in groups 1-3 (p = 0.19). Ischemic complications were more often observed in group 1 (n = 4, 8%) and 2 (n = 5, 8%) than group 3 (n = 7, 2%), p = 0.02. 90-day readmission (n = 99, 22%) and mortality rate (n = 10, 2.2%) were low and did not show any significant differences between the groups. In uni- and multivariate analysis ongoing therapy with acetylsalicylic acid was no independent risk factor for transfusion or severe complications. CONCLUSION: Perioperative continuation of therapy with acetylsalicylic acid in radical cystectomy is safe with no difference in intraoperative blood loss, transfusion rate, complications or mortality.

Prognostic Value of Molecular Breast Cancer Subtypes based on Her2, ESR1, PGR and Ki67 mRNA-Expression in Muscle Invasive Bladder Cancer.

INTRODUCTION: Gene expression analyses have identified similarities between bladder and breast cancer, where clinical risk stratification is based on Her2, ESR1, PGR and Ki67 expression. The aim of the study was to assess the respective marker gene expression in patients treated with radical cystectomy for muscle-invasive bladder cancer (MIBC) and to evaluate the applicability of breast cancer subtypes for MIBC risk stratification. MATERIALS & METHODS: 102 patients treated with radical cystectomy for MIBC were assessed. Using routine FFPE tissue and an IVD validated kit, mRNA expression was measured by single step RT-qPCR. Partition test were employed to define cut-off values for high or low marker gene expression. Association of expression with outcome was assessed using Kaplan-Meier analysis and multivariate cox regression analysis. Finally, we performed validation of our results in the MD-Anderson cohort (n=57). RESULTS: Cancer specific survival (CSS) was impaired in patients with high gene expression of Her2 (P=0.0009) and ESR1 (P=0.04). In the multivariate regression model Her2 expression remained significant for the prediction of CSS (HR=2.11, CI 1.11-4.21, P=0.024). Furthermore, molecular stratification by breast cancer subgroups was significant (P=0.023) for CSS prediction. Especially the differentiation between Her2-positive and Luminal A (HR=4.41, CI 1.53-18.71, P=0.004) and Luminal B (HR=1.96, CI 0.99-4.08, P=0.053) respectively was an independent prognostic parameter for CSS. External validation resulted in comparable risk stratification with differences in fractional subgroups distribution. CONCLUSION: Gene expression of Her2, ESR1, PGR, Ki67 and corresponding breast cancer subtypes allow a risk-stratification in MIBC, whereby Her2 overexpressing tumors reveal a particularly poor prognosis.

Novel insights into a reputably irreversible process: combined mRNA and miRNA profiling of tissue from vesicourethral anastomotic stenosis after radical prostatectomy.

PURPOSE: Until recently, tissue fibrosis-ultimately leading to permanent scaring-has been considered an irreversible process. However, recent findings indicate that it may be reversible after all. Vesicourethral anastomotic stenosis (VUAS) as fibrous narrowing is a frequent complication after radical prostatectomy with high recurrence rates and requires invasive treatment. The pathophysiology is poorly understood. Therefore, a combined mRNA and miRNA transcription profiling in tissue from VUAS was performed using nCounter technology. METHODS: To assess tissue morphology and fiber composition, histochemical staining was performed. RNA expression of healthy and fibrotic tissue of twelve patients was analyzed using the human miRNA panel v3 and mRNA PanCancer pathway panel on the nCounter gene1 system and qRT-PCR. Differential expression data analysis was performed using the nSolver software implementing the R-based advanced pathway analysis tool. miRWalk2.0 was used for miRNA target prediction. RESULTS: More linearized tissue architecture, increased collagens, and decreased elastic fibers were observed in VUAS samples. 23 miRNAs and 118 protein coding genes were differentially expressed (p < 0.01) in fibrotic tissue. miRNA target prediction and overlap analysis indicated an interaction of the strongest deregulated miRNAs with 29 deregulated mRNAs. Pathway analysis revealed alterations in DNA repair, cell cycle regulation, and TGF-beta signaling. qRT-PCR confirmed differential expression of top deregulated miRNAs and mRNAs. CONCLUSIONS: In VUAS tissue, severe alterations on mRNA and miRNA level are found. These consistent changes give insights into the pathogenesis of VUAS after radical prostatectomy and point to future options for transcriptomics-based risk stratification and targeted therapies.

[Molecular Characterisation of Urothelial Bladder Cancer: Will it Improve Patient Care?]. / Molekulare Charakterisierung des Urothelkarzinoms der Harnblase: Ist ein klinischer Nutzen in Sicht?

Urothelial bladder cancer is characterised by high recurrence and progression rates despite multimodal treatment. Only slight improvements have been achieved during the last decades. The current histopathological classification and clinical risk stratification tools are inaccurate. Hence, a better understanding of the tumour biology is essential for the improvement of patient care. The molecular characterisation of bladder cancer may be translated into useful diagnostic and predictive biomarkers. Many potential therapeutic targets have been identified such as FGFR3 (Fibroblast growth factor receptor 3), HER2 (human epidermal growth factor receptor 2) and PD1/PDL1 (programmed cell death-1). They need validation in clinical trials. We now review the molecular biology of urothelial bladder carcinoma and discuss clinical applications of biomarkers and targeted therapies.

[Detection of lymphovascular invasion in urothelial carcinoma of the bladder through D2-40 immunostaining]. / Detektion der lymphovaskulären Invasion mit D2-40-Immunhistochemie beim Urothelkarzinom der Harnblase.

BACKGROUND: Lymphovascular invasion (LVI) represents a surrogate marker for micrometastatic urothelial carcinoma of the bladder (UCB). OBJECTIVES: We evaluated whether D2-40 immunhistochemistry (IHC) alters detection of LVI when compared to conventional HE (hematoxylin-eosin) staining of UCB specimens in a blinded fashion. MATERIAL AND METHODS: HE- and D2-40-IHC-stained representative sections of 80 patients after radical cystectomy (RC) were re-reviewed. LVI detection rates were recorded and compared after blinded evaluation. RESULTS: LVI was present in 53 patients (66.3%) in HE-stained sections and in 44 patients (55%) in D2-40 stainings. In 13 patients, LVI (16.3%) was found in HE stained sections but not confirmed when IHC was applied (false positive when using IHC as a reference standard). D2-40 IHC identified LVI in 4 additional patients (5%) who were classified as LVI negative in conventional HE staining (false negative). 52 patients (65%) were lymph node negative (pN0), 21 of whom (40.4%) were LVI positive in conventional HE sections and 16 of whom (30.8%) were LVI positive in IHC. In 9 pN0 patients (17.3%), LVI was diagnosed in HE sections but not confirmed by IHC (false positive). D2-40 IHC identified LVI in 4 additional patients (7.7%) who were node negative and classified as LVI negative in conventional HE staining (false negative). In patients who experienced recurrence (n=35) and who were classified as pN0 at the time of RC, HE staining resulted both in false-positive (n=2; 5.7%) and false-negative (n=3; 8.6%) findings. CONCLUSION: Different detection rates of LVI were observed when using IHC with D2-40 in UCB patients compared to conventional HE staining. The routine use of D2-40 IHC should be considered in clinical trial design to improve risk stratification of pN0 patients after RC.

Velocity of early BCR-ABL transcript elimination as an optimized predictor of outcome in chronic myeloid leukemia (CML) patients in chronic phase on treatment with imatinib.

UNLABELLED: Early assessment of response at 3 months of tyrosine kinase inhibitor treatment has become an important tool to predict favorable outcome. We sought to investigate the impact of relative changes of BCR-ABL transcript levels within the initial 3 months of therapy. In order to achieve accurate data for high BCR-ABL levels at diagnosis, beta glucuronidase (GUS) was used as a reference gene. Within the German CML-Study IV, samples of 408 imatinib-treated patients were available in a single laboratory for both times, diagnosis and 3 months on treatment. In total, 301 of these were treatment-naïve at sample collection. RESULTS: (i) with regard to absolute transcript levels at diagnosis, no predictive cutoff could be identified; (ii) at 3 months, an individual reduction of BCR-ABL transcripts to the 0.35-fold of baseline level (0.46-log reduction, that is, roughly half-log) separated best (high risk: 16% of patients, 5-year overall survival (OS) 83% vs 98%, hazard ratio (HR) 6.3, P=0.001); (iii) at 3 months, a 6% BCR-ABL(IS) cutoff derived from BCR-ABL/GUS yielded a good and sensitive discrimination (high risk: 22% of patients, 5-year OS 85% vs 98%, HR 6.1, P=0.002). Patients at risk of disease progression can be identified precisely by the lack of a half-log reduction of BCR-ABL transcripts at 3 months.

Expression of transketolase-like gene 1 (TKTL1) depends on disease phase in patients with chronic myeloid leukaemia (CML).

PURPOSE: Overexpression of transketolase-like gene 1 (TKTL1) on RNA and protein level has been linked to tumour progression, metastasis and unfavourable patient outcome in many solid tumours. Chronic myeloid leukaemia (CML) cells show metabolic characteristics resembling deviations observed in TKTL1 overexpressing solid tumour cells. We therefore sought to evaluate TKTL1 gene expression in different phases of CML. METHODS: A total of 120 peripheral blood samples from 69 patients in various phases of CML and 21 healthy individuals were investigated. TKTL1 expression levels were determined by real-time quantitative polymerase chain reaction using LightCycler technology and normalised against beta-glucuronidase expression. RESULTS: A significantly lower TKTL1 expression was found in chronic phase (CP) CML patients compared to healthy controls. Lowest expression levels were observed in patients during blast crisis (BC). Baseline TKTL1 expression in CP patients did not have value in prognostication of subsequent favourable or dismal outcome. Further, more mature granulocytes showed significantly higher TKTL1 expression compared to immature CD34+ and CD34-/CD33+ cells both in healthy controls and in CML patients. CONCLUSION: TKTL1 expression levels appear to decline in the course of CML with lowest levels during BC. A potential reason is a shift of TKTL1-high-expressing mature granulocytes towards TKTL1-low-expressing immature cells and blasts.

MDR1 expression predicts outcome of Ph+ chronic phase CML patients on second-line nilotinib therapy after imatinib failure.

In the face of competing tyrosine kinase inhibitors (TKIs), identification of chronic myeloid leukemia (CML) patients expecting favorable response to second-line treatment is warranted. At the time of imatinib resistance, the investigation of multidrug-resistance protein 1 (MDR1) and BCR-ABL yielded the following results: (i) Patients with high MDR1 transcript levels showed superior response at 48 months as compared with low-level MDR1 patients: major molecular response (MMR) in 41% vs 16% (P=0.014), complete cytogenetic response (CCyR) in 58% vs 39% (P=0.044), and progression-free survival (PFS) in 67% vs 46% (P=0.032). (ii) Patients with BCR-ABL(IS) <28% achieved higher MMR rates (48% vs 21%, P=0.009). (iii) PFS at 48 months was associated with in vitro resistance of BCR-ABL kinase domain mutations: 63% (no mutation) vs 61% (sensitive, intermediately sensitive or unknown IC50 (median inhibitory concentration)) vs 23% (resistant, P=0.01). (iv) Single-nucleotide polymorphisms (SNPs) at positions 1236 and 2677 were associated with higher MDR1 expression in comparison to wild type. (v) Nilotinib was able to impede proliferation of MDR1-overexpressing imatinib-resistant cells. High MDR1 gene expression might identify patients whose mode of imatinib resistance is essentially determined by increased efflux activity of MDR1 and therefore can be overcome by second-line nilotinib treatment.

Early molecular and cytogenetic response is predictive for long-term progression-free and overall survival in chronic myeloid leukemia (CML).

In the face of competing first-line treatment options for CML, early prediction of prognosis on imatinib is desirable to assure favorable survival or otherwise consider the use of a second-generation tyrosine kinase inhibitor (TKI). A total of 1303 newly diagnosed imatinib-treated patients (pts) were investigated to correlate molecular and cytogenetic response at 3 and 6 months with progression-free and overall survival (PFS, OS). The persistence of BCR-ABL transcript levels >10% according to the international scale (BCR-ABL(IS)) at 3 months separated a high-risk group (28% of pts; 5-year OS: 87%) from a group with >1-10% BCR-ABL(IS) (41% of pts; 5-year OS: 94%; P=0.012) and from a group with ≤1% BCR-ABL(IS) (31% of pts; 5-year OS: 97%; P=0.004). Cytogenetics identified high-risk pts by >35% Philadelphia chromosome-positive metaphases (Ph+, 27% of pts; 5-year OS: 87%) compared with ≤35% Ph+ (73% of pts; 5-year OS: 95%; P=0.036). At 6 months, >1% BCR-ABL(IS) (37% of pts; 5-year OS: 89%) was associated with inferior survival compared with ≤1% (63% of pts; 5-year OS: 97%; P<0.001) and correspondingly >0% Ph+ (34% of pts; 5-year OS: 91%) compared with 0% Ph+ (66% of pts; 5-year OS: 97%; P=0.015). Treatment optimization is recommended for pts missing these landmarks.

Omacetaxine mepesuccinate prevents cytokine-dependent resistance to nilotinib in vitro: potential role of the common ß-subunit c of cytokine receptors.

Overcoming resistance against BCR-ABL-inhibitors in chronic myeloid leukemia (CML) is central to prevent progression to advanced phase disease. Kinase mutations of BCR-ABL and cytokine-mediated modulation of response to tyrosine kinase inhibitors (TKIs) are key mechanisms governing clinical response to imatinib and second generation TKIs. Omacetaxine mepesuccinate is effective in imatinib-resistant CML with reported stem cell activity. We specifically thought to explore omacetaxine in the context of the pan-resistant mutant T315I, and in its potential to modify cytokine-dependent resistance. Omacetaxine was investigated in cell lines and primary CD34+ enriched progenitor cells from patients with CML. Addition of cytokines, shown to revert the efficacy of TKIs in BCR-ABL-positive cells, does not affect omacetaxine mediated antiproliferative activity, neither in cell lines nor in primary CML CD34+ progenitor cells. Looking at potential mechanisms, we found marked downregulation of the common ß-subunit c of the cytokine-receptors (cCRßc) for IL3, IL5 and GM-CSF by omacetaxine in cell lines and primary progenitor cultures. The observed cytokine-independent in-vitro cytotoxicity of omacetaxine may be explained by downregulation of cCRßc. Whether this can be used clinically as a means to optimize the stem cell activity of TKIs merits further evaluation.

Chemotherapeutic alteration of ß-catenin and c-kit expression by imatinib in p16-positive squamous cell carcinoma compared to HPV-negative HNSCC cells in vitro.

The most common neoplasm arising in the upper aerodigestive tract is head and neck squamous cell carcinoma (HNSCC). Tumor growth, invasion and systemic dissemination is a multistep process of dysregulated cellular signaling pathways and an altered cell-cell and cell-matrix interaction. Aberrant Wnt/ß-catenin signaling is linked to tumor development and dissemination in several tumor entities. ß-catenin is a multifunctional protein within the canonical Wnt pathway, which is an important factor for reducing cell-cell adhesion in malignant tissue and for triggering cell cycle progression and unscheduled proliferation. Another pivotal factor in carcinogenesis is the tyrosine kinase receptor c-kit, which in the case of dysregulated expression is associated with neoplastic transformation in epithelial tissue. This study evaluates the expression pattern of secreted and nuclear ß-catenin and c-kit in p16-positive and HPV-negative squamous cell carcinomas (SCC) and the vulnerability of therapy with the tyrosine kinase inhibitor imatinib as a potential targeted treatment modality compared to platinum-based chemotherapeutic drugs. The different squamous tumor cell lines were incubated with increasing concentrations of carboplatin (3 or 7.5 µmol/ml) and imatinib (18 or 30 µmol/ml). ELISA and immunohistochemical methods were carried out after 48, 72, 120, 192 and 240 h. We detected a reliable trend towards significantly decreased cytosolic and nuclear ß-catenin and c-kit expression levels in p16-positive SCC and non-HPV HNSCC cells induced by imatinib exposure for an extended incubation period, whereas platinum-based agents had no or, at best, a slight influence. Virus-transformed squamous cell carcinoma (CERV196) cells were characterized by a reduced susceptibility to an imatinib-altered ß-catenin expression. Further studies are planned to investigate this observance in HPV-positive HNSCC in vitro. The implementation of a selective molecular therapy in established chemotherapeutic regimes may enhance the efficacy of platinum-based chemotherapy without increased toxicity and could thus improve the clinical outcome in HNSCC, irrespective of the HPV status.

Chemotherapeutic alteration of VEGF-/PDGF- and PDGF-Rα/ß expression by imatinib in HPV-transformed squamous cell carcinoma compared to HPV-negative HNSCC in vitro.

Head and neck squamous cell carcinoma (HNSCC) is an aggressive epithelial malignancy known to be the most common neoplasm appearing in the upper aerodigestive tract. The poor five-year survival rate has remained unchanged in the last decades despite the emergence of improved techniques in surgery, radiation and chemotherapy. In the last 20 years awareness of a subset of squamous cell carcinomas induced by oncogenic forms of the human papilloma virus (HPV) (high-risk types 16 and 18) has increased. The incidence of HPV-associated oropharyngeal cancer is rising, indicating the increased importance of the viral etiology. Cell proliferation, migration, induction of tumor vascularization and carcinogenesis, as well as invasion facilitation is regulated by a variety of angiogenic peptides like PDGF, PDGF-R and VEGF. They might be an encouraging target for biological anticancer therapy by inhibiting disrupted cellular signaling pathways. Imatinib has been shown to target specific tyrosine kinases, inhibiting proliferation in various cancer entities. The purpose of this study was to evaluate the expression pattern of angiogenic factors (VEGF, PDGF and PDGF-R) in HPV-positive (p16-CERV196 SCC) and (-negative squamous cell carcinoma (HNSCC). The study also evaluated the vulnerability of anti-angiogenesis therapy depending on the HPV status as potential treatment modality compared to established platinum-based chemotherapeutic drugs. The different squamous tumor cell lines were incubated with increasing concentrations of carboplatin (3 and 7.5 µmol) and imatinib (18 and 30 µmol). ELISA immunohistochemical methods were carried out after 48, 72, 120, 192 and 240 h. We demonstrated a significant reduction of VEGF and PDGF-Rα/ß expression patterns after incubation of imatinib in ELISA and immunohistochemical methods, irrespective of the HPV status of the tumor cells, whereas the application of carboplatin had no impact on the expression of angiogenic peptides. Viral oncogen-transformed squamous cell carcinoma (CERV196) cells were characterized by a reduced susceptibility for an imatinib-altered VEGF expression. Further studies are planned to investigate this observance in HPV-positive HNSCC in vitro. The implementation of a selective molecular anti-angiogenic therapy in established chemotherapeutic regimens may enhance the efficacy of platinum-based chemotherapy without an increased toxicity profile and could thus improve the clinical outcome in HNSCC, irrespective of the HPV status.

Synergistic effects of imatinib and carboplatin on VEGF, PDGF and PDGF-Rα/ß expression in squamous cell carcinoma of the head and neck in vitro.

Head and neck squamous cell carcinoma (HNSCC) is an aggressive epithelial malignancy. The development of new treatment modalities in order to improve long-term survival of patients with HNSCC is imperative. Numerous studies have demonstrated that carcinogenesis and tumor cell dissemination is influenced by the tumor microenvironment. The protein-kinase-receptors (PTKs) are essential elements of the intracellular signal transduction pathway and regulate cell growth, development and apoptosis. Cell proliferation, migration, induction of tumor vascularization and carcinogenesis, invasion is regulated by a variety of angiogenic factors, such as PDGF (platelet-derived growth factor), VEGF (vascular endothelial growth factor) and their respective tyrosine kinase receptors (PDGF-R and VEGF-R). They present promising targets for anti-cancer therapy through abrogation of impaired signaling pathways. Indeed, imatinib, a small molecule drug targeting these protein kinases, has antiproliferative effects in several cancer types. The purpose of this study was to investigate the potential synergism of imatinib and carboplatin on the expression of PDGF, PDGF-R α/ß and VEGF in different HNSCC cell lines. Several tumor cell lines were subjected to increasing concentrations of carboplatin (3 and 7.5 µmol/l) and imatinib (18 and 30 µmol/l) and ELISA, immunohistochemical methods and RQ-PRC after 48, 72, 120 and 240 h were used to assess their expression levels. While PDGF-Rα/ß expression was unimpaired at lower imatinib concentrations (18 µmol/l), PDGF-Rα/ß expression was suppressed at 30 µmol/l, and suppression was enhanced by the presence of carboplatin. By RQ-PCR, a significant reduction of PDGF-Rα/ß expression was detected (p<0.5). We observed explicit significant reduction in VEGF levels with increasing concentrations of imatinib and with the combination of the two chemotherapeutic drugs (p<0.5). We report for the first time evidence of synergism of imatinib and carboplatin in suppressing VEGF, PDGF and PDGF-Rα/ß expression in HNSCC.

Harmonization of molecular monitoring of CML therapy in Europe.

The high efficacy of the standard treatment of chronic myeloid leukemia (CML) with imatinib has prompted the need for accurate methods to monitor response at levels below the landmark of complete cytogenetic remission. Quantification of BCR-ABL transcripts has proven to be the most sensitive method available, and has shown prognostic impact with regard to progression-free survival. Until recently, variations in methods used to quantify BCR-ABL made it difficult to compare results between laboratories. An international program is now underway to harmonize the reporting of results according to an international scale (IS). In this review, we consider the background to the IS and the progress that has been made to date, with a particular focus on ongoing harmonization efforts in Europe. We provide recommendations for the propagation of the IS by national or regional laboratory networks.

The molecular anatomy of the FIP1L1-PDGFRA fusion gene.

The FIP1L1-PDGFRA fusion gene is a recurrent molecular abnormality in patients with eosinophilia-associated myeloproliferative neoplasms. We characterized FIP1L1-PDGFRA junction sequences from 113 patients at the mRNA (n=113) and genomic DNA (n=85) levels. Transcript types could be assigned in 109 patients as type A (n=50, 46%) or B (n=47, 43%), which were created by cryptic acceptor splice sites in different introns of FIP1L1 (type A) or within PDGFRA exon 12 (type B). We also characterized a new transcript type C (n=12, 11%) in which both genomic breakpoints fell within coding sequences creating a hybrid exon without use of a cryptic acceptor splice site. The location of genomic breakpoints within PDGFRA and the availability of AG splice sites determine the transcript type and restrict the FIP1L1 exons used for the creation of the fusion. Stretches of overlapping sequences were identified at the genomic junction site, suggesting that the FIP1L1-PDGFRA fusion is created by illegitimate non-homologous end-joining. Statistical analyses provided evidence for clustering of breakpoints within FIP1L1 that may be related to DNA- or chromatin-related structural features. The variability in the anatomy of the FIP1L1-PDGFRA fusion has important implications for strategies to detect the fusion at diagnosis or for monitoring response to treatment.

Harmonization of BCR-ABL mRNA quantification using a uniform multifunctional control plasmid in 37 international laboratories.

Individualized PCR strategies hamper comparability of molecular results between different laboratories in several fields of medicine. To harmonize BCR-ABL mRNA quantification an international multicenter trial involving 37 laboratories in 14 countries was initiated using 10 samples, each containing various dilutions (10, 2, 1 and 0.1%) of b3a2 or b2a2 BCR-ABL positive in normal leukocytes and negative controls. A novel control plasmid (pME-2) was designed for external calibration containing BCR-ABL and glucuronidase-beta (GUS) sequences. Median BCR-ABL/ABL ratios were 9.1, 1.8, 0.85 and 0.11% in b3a2 samples and 9.5, 1.6, 0.84 and 0.11% in b2a2 samples. Median BCR-ABL/GUS ratios were 3.4, 0.77, 0.37 and 0.042% in b3a2 samples and 2.8, 0.48, 0.29 and 0.031% in b2a2 samples. The coefficients of variation were 0.62 for ratios BCR-ABL/ABL and 1.03 for ratios BCR-ABL/GUS. Five of 37 evaluable participating laboratories (13%) detected low BCR-ABL copy numbers in negative control samples; one laboratory failed to detect BCR-ABL in a low-level sample. We conclude that the use of a common control plasmid does indeed improve comparability of BCR-ABL mRNA quantification results. However, further standardizing efforts like introducing a calibrator and regular control rounds are needed.

Expression of the p210BCR-ABL oncoprotein drives centrosomal hypertrophy and clonal evolution in human U937 cells.

Centrosomes play fundamental roles in mitotic spindle organization, chromosome segregation and maintenance of genetic stability. Recently, we have shown that centrosome aberrations occur early in chronic myeloid leukemia (CML) and are induced by imatinib in normal fibroblasts in vitro. To investigate the influence of BCR-ABL on centrosomes, we performed long-term in vitro experiments employing the conditionally p210BCR-ABL-expressing (tetracycline-inducible promoter) human monocytic cell line U937p210BCR-ABL/c6 as a model of CML chronic phase. Centrosome hypertrophy was detectable after 4 weeks of transgene expression onset, increasing up to a rate of 25.7% aberrant cells within 13 weeks of propagation. This concurred with clonal expansion of aneuploid cells displaying a hyperdiploid phenotype with 57 chromosomes. Partial reversibility of centrosome aberrations (26-8%) was achieved under prolonged propagation (14 weeks) after abortion of induction and bcr-abl silencing using small interfering RNA. Therapeutic doses of imatinib did not revert the aberrant phenotype, but counteracted the observed reverting effect of bcr-abl gene expression switch off. Suggesting a mechanistic model that features distinct abl-related tyrosine kinase activity levels as essential determinants of centrosomal integrity, this is the first report mechanistically linking p210BCR-ABL oncoprotein activity to centrosomal hypertrophy.