Relevant bleeding diathesis due to acquired factor XIII deficiency

BACKGROUND

Acquired factor XIII (FXIII) deficiency is associated with reduced clot firmness and increased bleeding in patients undergoing major surgery. In contrast, only limited information is available on the haemostatic relevance of acquired FXIII deficiency in non-surgical patients.

CASE REPORT

An 81-year-old patient, who had experienced acute type-A dissection of the aorta eight years earlier, presented with a 3-year history of progressive mucocutaneous and soft-tissue bleeding. Diagnostic work-up was unremarkable for global coagulation tests, but FXIII and alpha2-antiplasmin were decreased to 33% and 27%, respectively, while plasma D-dimer was elevated to > 35 mg/l. A FXIII inhibitor was excluded by mixing studies. CT scanning revealed a massively elongated and progressively dilated aorta with a false lumen reaching from the left carotid artery to the iliac bifurcation. Bleeding control was achieved by single doses of FXIII at 20-30 IU/kg body weight and tailored oral tranexamic acid.

CONCLUSION

Acquired FXIII deficiency with activity levels of 30-35% may confer a severe bleeding tendency in non-surgical patients, especially in the context of increased thrombin an fibrin generation.

Abstract P2-10-15: Evaluation of Prognostic and Predictive Performance of Breast Cancer Index and Its Components in Hormonal Receptor-Positive Breast Cancer Patients: A TransATAC Study

Background: The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial compared the efficacy and safety of 5 years of anastrozole with tamoxifen as adjuvant treatment for postmenopausal women with localized HR+ breast cancer. At a median follow-up of 10 years, a statistically significant improvement with anastrozole vs. tamoxifen for disease-free survival, time to recurrence and time to distant recurrence was observed. The HOXB13:IL17BR gene expression ratio (H/I) quantifies recurrence risk in ER positive (ER+) breast cancer patients and is predictive of benefit from endocrine therapy. Molecular Grade Index (MGI) is a five-gene index that provides quantitative and objective molecular assessment of tumor grade and proliferative status. Breast Cancer Index (BCI) combines H/I and MGI into a continuous risk model that provides a likelihood of distant recurrence in patients treated with endocrine therapy, and efficacy from neoadjuvant chemotherapy. In the current analysis, evaluation of the prognostic and predictive performance of BCI, H/I and MGI in the ATAC study cohort was conducted.

Methods: Under the TransATAC protocol, formalin-fixed, paraffin-embedded (FFPE) blocks of primary tumor were collected from HR+ patients from each monotherapy arm. The current study examined samples collected from the United Kingdom, which constituted 79% of the collection. RNA extracted from 1102 samples from the TransATAC study was amplified, converted to cDNA and subjected to RT-PCR with primers and probes to HOXB13, IL17BR, BUB1A, CENPA, NEK2, RACGAP1 and RRM2. H/I, MGI and BCI were calculated and risk groups were determined using pre-specified cutpoints.

Results: Of 1102 tumor specimens assayed, 29 failed QC criteria, leaving 1073 samples for analysis. Detailed results on the prognostic and predictive performance of BCI, H/I and MGI will be presented. Data on whether BCI and its components provided independent prognostic information in the presence of classical variables, their prognostic value for risk of late recurrence, interaction by treatment arms, and comparative performance vs other models will also be discussed.

Discussion: The ATAC trial has established the long-term efficacy and safety of anastrozole over tamoxifen as initial adjuvant treatment for post-menopausal early stage breast cancer patients. Continued efforts are needed to improve on quantification of residual risk in patients who were treated with endocrine therapy to guide decision-making in selecting additional adjuvant chemotherapy and/or administering extended endocrine treatment. This study will help to establish the strategy to more effectively select patients for adjuvant therapies.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-15.

Abstract P1-07-13: Prognostic relevance of statistically standardized estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) in tamoxifen(TAM)-treated NCIC CTG MA.14 patients

Background: Poor inter-laboratory comparability of common clinically used breast cancer biomarkers led to a proposal of statistical standardization (SS) of laboratory results, similar to bone mineral density (BMD) z-scores. This analysis is the first utilization of SS in a trial where all women received TAM.

Methods: MA.14 allocated 667 postmenopausal women to TAM +/− Octreotide LAR (OCT) based on locally determined ER/PR, without HER2 status. At 9.8 yrs median follow-up, the secondary endpoint of relapse-free survival (RFS) had a non-significant hazard ratio (HR) for TAM-OCT to TAM of 0.87 (95% CI 0.63–1.21; p = 0.40). 299 patients who were representative of MA.14 patients by treatment and stratification factors (exact Fisher p-values=0.19–0.90) had their tumors centrally assessed for ER, PR, and HER2 by RT-PCR. Continuous values were used for SS of each biomarker. Univariate (uni) assessment used similar categorizations as those for BMD, assigning ER/PR/HER2 values by number of standard deviations (SD) about the mean (Group 1, z-score ≥1.0 SD below mean; Group 2, z-score <1.0 SD below mean; Group 3, z-score ≤1.0 SD above mean; Group 4, z-score >1.0 SD above mean). A log-rank statistic was used to test for differences between SS biomarker groups with K-M plots for graphical description. Multivariate (multi) effects of SS biomarkers and baseline patient characteristics on RFS were examined with exploratory (un)stratified Cox step-wise forward regression, adding a factor if likelihood ratio criterion was p ≤ 0.05. Sensitivity analyses used a prior external HER2+ cut-point of ≥1.32 SD.

Results: 292 patient samples passing internal analytical quality control were included in this analysis. Uni analyses indicated SS ER was not associated with RFS (p = 0.31). SS PR had a significant uni effect on RFS [p = 0.03; Group 4 compared to Group 1, HR of 0.33 (95% CI 0.12–0.90); Group 3 compared to Group 1, HR of 0.42 (95% CI 0.21–0.83); and Group 2 compared to Group 1 HR of 0.70 (95%CI 0.36–1.37)]. SS HER2 also had a significant uni effect on RFS [p = 0.004; Group 4 compared to Group 1, HR of 0.90 (95% CI 0.37–2.16)]; Group 3 compared to Group 1, HR of 0.39 (95% CI 0.18–0.84); and, Group 2 compared to Group 1, HR of 0.34 (95% CI 0.16–0.70)]. Multi stratified/unstratified Cox models indicated T1 tumours (p = 0.02/p = 0.0002) and higher SS PR (p = 0.02/0.01) were associated with significantly longer RFS; other unstratified results showed that N-ve patients had better RFS (p < .0001), while local ER/PR status did not impact RFS (p > 0.05). The HER2+ cut-point of ≥1.32 SD indicated directionally worse RFS (uni p-value=0.05; multi p-value=0.06).

Discussion: In MA.14, all women received TAM. Local ER/PR status using categorical or semi-quantitative values did not impact RFS. A statistically standardized approach using continuous centralized ER, PR, HER2 by RT-PCR demonstrated that increasing PR values were associated with better RFS. Evaluation in other trials may provide support for this methodology.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-07-13.

Breast Cancer Index predicts pathological complete response and eligibility for breast conserving surgery in breast cancer patients treated with neoadjuvant chemotherapy

BACKGROUND

The aim of neoadjuvant chemotherapy is to increase the likelihood of successful breast conservation surgery (BCS). Accurate identification of BCS candidates is a diagnostic challenge. Breast Cancer Index (BCI) predicts recurrence risk in estrogen receptor+lymph node-breast cancer. Performance of BCI to predict chemosensitivity based on pathological complete response (pCR) and BCS was assessed.

METHODS

Real-time RT-PCR BCI assay was conducted using tumor samples from 150 breast cancer patients treated with neoadjuvant chemotherapy. Logistical regression and c-index were used to assess predictive strength and additive accuracy of BCI beyond clinicopathologic factors.

RESULTS

BCI classified 42% of patients as low, 35% as intermediate and 23% as high risk. Low BCI risk group had 98.4% negative predictive value (NPV) for pCR and 86% NPV for BCS. High versus low BCI group had a 34 and 5.8 greater likelihood of achieving pCR and BCS, respectively (P=0.0055; P=0.0022). BCI increased c-index for pCR (0.875-0.924; P=0.017) and BCS prediction (0.788-0.843; P=0.027) beyond clinicopathologic factors.

CONCLUSIONS

BCI significantly predicted pCR and BCS beyond clinicopathologic factors. High NPVs indicate that BCI could be a useful tool to identify breast cancer patients who are not eligible for neoadjuvant chemotherapy. These results suggest that BCI could be used to assess both chemosensitivity and eligibility for BCS.

P5-13-08: Breast Cancer Index Predicts Likelihood of Breast Conservation Surgery after Neoadjuvant Chemotherapy

Introduction: Neoadjuvant chemotherapy increases the likelihood that breast conservation therapy for breast cancer patients will be successful. Breast Cancer Index (BCI), a gene expression assay combining HoxB13/IL17BR ratio and Molecular Grade Index (MGI), is prognostic for the risk of distant recurrence and overall survival in tamoxifen-treated and untreated breast cancer patients. It was previously reported that high risk patients, as determined by BCI, had a 10-fold greater probability of pathologic complete response (pCR) with neoadjuvant chemotherapy than low risk patients. The aim of the current study was to examine the relationship between BCI score and the use of breast conservation surgery (BCS) following treatment with neoadjuvant chemotherapy.

Material and Methods: A total of 145 women (tumor size T1, T2 and T3) were treated with neoadjuvant cheomtherapy for stage I-III breast cancer. RNA was extracted from FFPE tumor samples and a real-time RT-PCR assay was completed to generate a BCI score and risk group categorization as previously described (Jerevall et al. Br J Cancer 2011). The relationship between BCS, BCI and clinicopathological factors was examined using univariate and multivariate logistic regression.

Results: Of the 145 patients (67% ER+, 54% PR+, 57% >50 y old), 48 (33.1%) underwent BCS. BCI categorized 62 (43%) of patients as low, 50 (34%) as intermediate and 33 (23%) as high risk. The rate of BCS for the three BCI risk categories was 15% (low risk), 48% (intermediate risk) and 45% (high risk). In the low risk group, the rate of BCS was 15% corresponding to a NPV of 85%. This is consistent with previous data from the same cohort, where the NPV of BCI for pCR was 98.4% with only one patient in the low risk group achieving pCR. In univariate analysis, pathological tumor size (pT), ER, PR, grade and BCI were predictors of BCS. A higher BCI score was associated with higher likelihood of BCS (odds ratio of 3.90; CI: 1.45−10.49; p=0.0069). In multivariate analysis, pT and BCI remained significantly associated with BCS, while ER status was not (p=0.23). Results were similar in the subset of patients with T1 and T2 tumors (N=97). In this subset, BCI categorized 42% of patients as low, 37% as intermediate and 21% as high risk and the rate of BCS was 22%, 64% and 60%, respectively. In multivariate analysis of this subset, only BCI was significantly associated with BCS. In all patients, the concordance index based on a model with pT alone was 0.695. When BCI was incorporated into the model with pT, the concordance index increased to 0.801 (p= 0.0002).

Conclusion: In this study, we have shown that patients with higher BCI scores were associated with a higher likelihood of receiving BCS after neoadjuvant chemotherapy. Addition of BCI to tumor size increased accuracy in predicting likelihood of BCS. BCI along with standard pathological factors may improve estimation of individual probability of BCS after neoadjuvant chemotherapy. This study gives rise to the hypothesis that patients with low BCI should not be eligible for neoadjuvant chemotherapy since the likelihood of breast conservation is low. Further large confirmatory studies are necessary.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-13-08.

P2-12-12: Prognostic Utility of Breast Cancer Index for Late Relapse in Patients with Early Stage Breast Cancer

Background

Residual risk of relapse remains a substantial concern for breast cancer patients as greater than half of recurrences occur beyond the initial 5y of tamoxifen therapy. First generation multigene signatures provide further prognostic information to standard clinical and pathological factors, however, their utility is strongest for predicting early relapse (≤5y post-diagnosis), and they have limited prognostic value for late metastatic risk. Breast Cancer Index (BCI), a continuous risk index based on the combination of HOXB13:IL17BR (H:I) and the molecular grade index (MGI), estimates the individual risk of recurrence in ER+, LN- breast cancer patients. In this study, the prognostic performance of BCI for predicting early versus late relapse (≤5y vs >5y post-diagnosis) was examined.

Methods: Gene expression profiling was performed on RNA extracted from FFPE tumor samples from untreated, postmenopausal, ER+ early stage breast cancer patients in the randomized Stockholm Trial. RT-PCR assay, pre-defined BCI score, H:I and MGI cut-points, and risk group categorization were done as previously described (Jerevall et al., Br J Cancer 2011). Association of gene expression data with the clinical endpoint of time to distant metastasis was assessed by Kaplan-Meier analysis using the log rank test; time-varying coefficient Cox proportional models were used to estimate the time-dependent hazard ratios (HRs).

Results: Analyses included 274 ER+, LN- patients (51% PR+, 87% HER2−, 63% grade 2, 17.7 y median follow-up) who did not receive adjuvant tamoxifen treatment. BCI was significantly associated with 10-year distant metastasis-free survival, with probabilities of 91% (86-96%), 82% (74-91%), and 65% (52-80%) for the low, intermediate, and high-risk BCI groups, respectively (HR high versus low-risk group = 4.31; 95%CI, 2.23−8.33; P=0.00001). Risk stratification for the first 5-y post-diagnosis using time-varying coefficient Cox models showed both MGI and BCI were significantly prognostic with HRs of 6.13 (95% CI: 2.11−17.8; P=0.0009) and 5.77 (95% CI: 2.16−15.39; P=0.0005). For prediction of late relapse in the subset of patients that remained distant metastasis-free for at least 5-y (N=221), MGI decreased in prognostic utility (HR 1.65, 0.76−3.56; P=0.2), consistent with other proliferation-based gene signatures. In comparison, both H:I and BCI were significantly associated with risk of late relapse [HRs 2.89 (1.31−6.36; P=0.009); 3.31(1.3−8.39); P=0.012].

Prediction of late recurrences by breast cancer index in the NCIC CTG MA.17 cohort

2

Background: The MA.17 trial demonstrated that extended adjuvant endocrine therapy with letrozole after 5-y of tamoxifen markedly reduced the risk of recurrence in women with ER+ early stage breast cancer. This trial provides an opportunity to assess the ability of biomarkers to predict late recurrences in ER+ breast cancer. The Breast Cancer Index (BCI), a continuous risk index based on the combination of HOXB13:IL17BR (H:I) and the molecular grade index (MGI), estimates the individual risk of recurrence in ER+ breast cancer patients. In this study, the prognostic utility of BCI to predict late recurrences was examined.

Methods: FFPE tumor blocks were collected from patients who experienced a breast cancer recurrence up to unblinding of MA.17. Controls were matched 2:1 for age, tumor size, nodal status and prior chemotherapy, and were disease free for longer than cases. All cases were reviewed for standard histopathology and evaluated using the real-time RT-PCR BCI assay.

Results: Patient characteristics for the case-control study were similar to that from the overall study. Characteristics for cases (N=83) and controls (N=166) were not significantly different except for treatment. A higher percentage of controls compared to cases tended to be categorized as low risk by BCI (58% vs 43%), while a lower percentage of controls than cases tended to be categorized as high risk by BCI (34% vs 24%). In univariate analysis, treatment, BCI, H:I and HOXB13, but not tumor grade or MGI, were significant predictors of late recurrence. After adjusting for standard variables (age, tumor grade and treatment), BCI (OR 2.37; P=0.03), H:I (OR 2.55; P=0.04) and HOXB13 (OR 1.35; P=0.02) remained significant predictors of recurrence. HOXB13 expression at diagnosis predicted patient benefit from extended endocrine therapy with letrozole.

Conclusions: In this case-controlled study, the data demonstrate that BCI is a significant predictor of late recurrences in ER+ patients following 5-y of tamoxifen. The prognostic performance of BCI to predict late recurrences was largely dependent on HOXB13 expression. The integration of H:I and MGI within BCI provides prognostic utility for both early and late recurrences.

High bone turnover and accumulation of osteoid in patients with neurofibromatosis 1

Although it is known that neurofibromatosis 1 (NF1) patients suffer from vitamin D deficiency and display decreased bone mineral density (BMD), a systematic clinical and histomorphometrical analysis is absent. Our data demonstrate that NF1 patients display high bone turnover and accumulation of osteoid and that supplementation of vitamin D has a beneficial effect on their BMD.

INTRODUCTION

Neurofibromatosis 1 results in a wide range of clinical manifestations, including decreased BMD. Although it has been reported that NF1 patients have decreased vitamin D serum levels, the manifestation of the disease at the bone tissue level has rarely been analyzed.

METHODS

Thus, we performed a clinical evaluation of 14 NF1 patients in comparison to age- and sex-matched control individuals. The analysis included dual X-ray absorptiometry osteodensitometry, laboratory parameters, histomorphometric and quantitative backscattered electron imaging (qBEI) analyses of undecalcified bone biopsies.

RESULTS

NF1 patients display significantly lower 25-(OH)-cholecalciferol serum levels and decreased BMD compared to control individuals. Histomorphometric analysis did not only reveal a reduced trabecular bone volume in biopsies from NF1 patients, but also a significantly increased osteoid volume and increased numbers of osteoblasts and osteoclasts. Moreover, qBEI analysis revealed a significant decrease of the calcium content in biopsies from NF1 patients. To address the question whether a normalization of calcium homeostasis improves BMD in NF1 patients, we treated four patients with cholecalciferol for 1 year, which resulted in a significant increase of BMD.

CONCLUSION

Taken together, our data provide the first complete histomorphometric analysis from NF1 patients. Moreover, they suggest that low vitamin D levels significantly contribute to the skeletal defects associated with the disease.

Non-destructive and radiochemical determination of the neutron-induced production cross section of I-129 from Te and other neutron-induced cross sections on Te at 14.7 MeV

Cross sections of twelve neutron-induced reactions on tellurium at 14.7 MeV have been determined. Among them are the (n,2n) cross sections for the production of both 129Te isomers which were determined using gamma ray spectrometry. These reactions dominate the cosmogenic production of 129I in meteoroids and are therefore of special importance. In addition, the neutron-induced cross section on Te at 14.7 MeV for the production of 129I was also determined directly by accelerator mass spectrometry (AMS) after radiochemical separation. The results for the production cross section of 129I determined by the two methods agree within 5%.

On the origin of129I in rain water near Zürich

129I concentrations in precipitation at Dübendorf/Zürich, Switzerland, have been determined with monthly resolution for almost three years in the mid 1990s. The results confirm that annual mean129I concentrations in precipitation in central Europe have remained about constant since the late 1980s. Liquid and gaseous emissions from the nuclear fuel reprocessing plants at Sellafield and La Hague are discussed as the only possible sources of129I in precipitation in central Europe. Based on an upper limit estimate for iodine transferred from the sea to the atmosphere, the gaseous discharges constitute the potentially bigger129I reservoir for precipitation. Moreover, the time dependence of the annual gaseous129I releases from Sellafield and La Hague correlates much better with the129I concentrations in precipitation in central Europe since the late 1980s than does the time dependence of the liquid emissions from these sites. At monthly resolution, the129I concentrations in the precipitation samples close to Zürich exhibit a large variability. A meteorological transport analysis was carried out for four selected months with particularly low or high observed129I concentrations. It was found that meteorological transport alone, based upon assimilated wind fields and observed precipitation values, can not directly account for the large month-to-month variability.

Dementia and leukoencephalopathy due to lymphomatosis cerebri

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL). Clinically, the disease typically presents with a rapidly progressive dementia and unsteadiness of gait. Its presentation on cerebral MRI, which is characterised by diffuse leukoencephalopathy without contrast enhancement, often causes diagnostic confusion1 with suspected diagnoses ranging from Binswanger's disease to leukoencephalopathy or encephalomyelitis. Here we report a patient with subacute dementia and diffuse bilateral white matter changes in the cerebral hemispheres and additional involvement of the brainstem, basal ganglia and thalamus on MRI. Initially, she was considered to suffer from an autoimmune encephalitis, transiently responded to immunosuppression but then developed multiple solid appearing cerebral lymphomas.

Galactic-cosmic-ray-produced 3He in a ferromanganese crust: any supernova 60Fe excess on earth?

An excess of 60Fe in 2.4-3.2 x 10(6) year old ferromanganese crust (237 KD) from the deep Pacific Ocean has been considered as evidence for the delivery of debris from a nearby supernova explosion to Earth. Extremely high ;{3}He/;{4}He (up to 6.12 x 10(-3)) and 3He concentrations (up to 8 x 10(9) atoms/g) measured in 237 KD cannot be supernova-derived. The helium is produced by galactic cosmic rays (GCR) and delivered in micrometeorites that have survived atmospheric entry to be trapped by the crust. 60Fe is produced by GCR reactions on Ni in extraterrestrial material. The maximum (3)He/(60)Fe of 237 KD (80-850) is comparable to the GCR (3)He/(60)Fe production ratio (400-500) predicted for Ni-bearing minerals in iron meteorites. The excess 60Fe can be plausibly explained by the presence of micrometeorites trapped by the crust, rather than injection from a supernova source.

Iodine-129 in soils from Northern Ukraine and the retrospective dosimetry of the iodine-131 exposure after the Chernobyl accident

Forty-eight soil profiles down to a depth of 40 cm were taken in Russia and Ukraine in 1995 and 1997, respectively, in order to investigate the feasibility of retrospective dosimetry of the 131I exposure after the Chernobyl accident via the long-lived 129I. The sampling sites covered areas almost not affected by fallout from the Chernobyl accident such as Moscow/Russia and the Zhitomir district in Ukraine as well as the highly contaminated Korosten and Narodici districts in Ukraine. 129I was analyzed by radiochemical neutron activation analysis (RNAA) and accelerator mass spectrometry (AMS). 127I was measured for some profiles by RNAA or ion chromatography (IC). The results for 127I demonstrated large differences in the capabilities of the soils to store iodine over long time spans. The depth profiles of 129I and of 137Cs showed large differences in the migration behavior between the two nuclides but also for each nuclide among the different sampling sites. Though it cannot be quantified how much 129I and 137Cs was lost out of the soil columns into deeper depths, the inventories in the columns were taken as proxies for the total inventories. For 129I, these inventories were at least three orders of magnitude higher than a pre-nuclear value of 0.084+/-0.017 mBq m(-2) derived from a soil profile taken in 1939 in Lutovinovo/Russia. From the samples from Moscow and Zhitomir, a pre-Chernobyl 129I inventory of (44+/-24) mBq m(-2) was determined, limiting the feasibility of 129I retrospective dosimetry to areas where the 129I inventories exceed 100 mBq m(-2). Higher average 129I inventories in the Korosten and Narodici districts of 130 and 848 mBq m(-2), respectively, allowed determination of the 129I fallout due to the Chernobyl accident. Based on the total 129I inventories and on literature data for the atomic ratio of 129I/131I=13.6+/-2.8 for the Chernobyl emissions and on aggregated dose coefficients for 131I, the thyroid exposure due to 131I after the Chernobyl accident was estimated for the inhabitants of four villages in the Korosten and of three villages in the Narodici districts. The limitations and uncertainties of the 129I retrospective dosimetry are discussed.

Quantitative monitoring of the mRNA expression pattern of the TGF-beta-isoforms (beta 1, beta 2, beta 3) during transdifferentiation of hepatic stellate cells using a newly developed real-time SYBR Green PCR

Current methods to determine the mRNA of the TGF-beta-isoforms, beta 1, beta 2, and beta 3, are not sensitive enough to detect small alterations in the expression levels. Therefore, we established a SYBR Green I-based real-time quantitative PCR procedure with fragment-specific standards. The advantage of gene-specific quantification is the possibility to be abstain from the need to compare results with a house-keeping gene having a different sequence and PCR efficiency. Reproducibility of the results and analytical variances of the real-time PCR assays were tested. In transdifferentiating rat hepatic stellate cells (HSC) the TGF-beta 1-mRNA was found to be the predominant isoform expressed followed by TGF-beta 3 and low amounts of TGF-beta 2-mRNA. An alteration of the TGF-beta 1,-beta 2, and -beta 3 ratio during HSC transdifferentiation could not be detected. Furthermore, the GAPDH mRNA expression varied during HSC activation, and thus is not recommended as a standard in real-time PCR quantifications.

Identification of a promoter in position 56 within the long control region of human papillomavirus type 18

The expression of the oncogenes E6 and E7 of the cervical cancer associated human papillomavirus type 18 was shown to be directed from the promoter in position 105 (P105), which is reportedly the only early promoter located within the long control region (LCR). However, in C33A cells transiently transfected with a reporter construct containing the LCR of HPV18 in front of the luciferase gene a transcript initiating at position 56 was present in addition to those initiating from the P105. A perfect TATA Box consensus sequence 30 bp further upstream, which is highly conserved among HPVs associated with cervical cancer, was required for the activity of this novel promoter, denoted here as P56. The P56 specific transcript obviously depends on promoter downstream sequences, since transcripts initiating from the P56 were not present when the CAT gene was cloned downstream of the LCR. We detected transcripts initiating from both the P105 and the P56 in primary keratinocytes harboring episomal HPV18 as well as in the HPV 18 positive cervical carcinoma cell lines HeLa, C4-1 and SW756. Our data suggest that in HPV18, the expression of the early viral proteins including the oncogenes might be directed from a second promoter, located within the LCR.

Expression of Pbx1b during mammalian organogenesis

Mammalian Pbx genes (Pbx1-3) encode a family of TALE homeodomain proteins that function as transcriptional regulators in numerous cell types (Curr. Opin. Genet. Dev. 8 (1998) 423). The present study highlights distinctive features of Pbx1b expression during mouse embryonic development as a framework to understand its biological functions. Immunohistochemical analyses demonstrate extensive expression of Pbx1b throughout post-implantation development, with highest levels observed during early to mid-gestation. Its initial distribution is predominantly associated with condensing mesoderm, however, Pbx1b displays dynamic expression patterns in derivatives of all principal germ layers. In particular, Pbx1b localizes to sites of mesenchymal-epithelial interactions during periods of active morphogenesis in tissues such as the lung, kidney, tooth buds and vibrissae follicles. Furthermore, BrdU labeling studies reveal that Pbx1b expression domains partially overlap with regions of cellular proliferation. Taken together, these data suggest that Pbx1b contributes to multiple cellular processes during embryogenesis, which may include roles in cell-autonomous regulation as well as in the mediation of tissue interactions.

Wet and dry deposition of 129I in Seville (Spain) measured by accelerator mass spectrometry

Iodine-129 (T1/2 = 1.57 x 10(7) yr) concentrations have been determined by accelerator mass spectrometry in rainwater samples taken at Seville (southwestern Spain) in 1996 and 1997. This technique allows a reduction in the detection limits for this radionuclide in comparison to radiometric counting and other mass spectrometric methods such as ICP-MS. Typical 129I concentrations range from 4.7 x 10(7) 129I atoms/l (19.2%) to 4.97 x 10(9) 129I atoms/l (5.9%), while 129I depositions are normally in the order of 10(8)-10(10) atoms/m2d. These values agree well with other results obtained for recent rainwater samples collected in Europe. Apart from these, the relationship between 129I deposition and some atmospheric factors has been analyzed, showing the importance of the precipitation rate and the concentration of suspended matter in it.

HoxA9-mediated immortalization of myeloid progenitors requires functional interactions with TALE cofactors Pbx and Meis

Specific Hox genes are implicated in leukemic transformation, and their selective genetic collaboration with TALE homeobox genes, Pbx and Meis, accentuates their oncogenic potential. The molecular mechanisms underlying these coordinate functions, however, have not been characterized. In this study, we demonstrate that HoxA9 requires its Pbx interaction motif as well as its amino terminus to enhance the clonogenic potential of myeloid progenitors in vitro. We further show that HoxA9 forms functional trimeric DNA binding complexes with Pbx and Meis-like proteins on a modified enhancer. DNA binding complexes containing HoxA9 and TALE homeoproteins display cooperative transcriptional activity and are present in leukemic cells. Trimeric complex formation on its own, however, is not sufficient for HoxA9-mediated immortalization. Rather, structure-function analyses demonstrate that domains of HoxA9 which are necessary for cellular transformation are coincident with those required for trimer-mediated transcriptional activation. Furthermore, the amino terminus of HoxA9 provides essential transcriptional effector properties and its requirement for myeloid transformation can be functionally replaced by the VP16 activation domain. These data suggest that biochemical interactions between HoxA9 and TALE homeoproteins mediate cellular transformation in hematopoietic cells, and that their transcriptional activity in higher order DNA binding complexes provides a molecular basis for their collaborative roles in leukemogenesis.