Hypoxia-induced treatment failure in advanced squamous cell carcinoma of the uterine cervix is primarily due to hypoxia-induced radiation resistance rather than hypoxia-induced metastasis

Poor outcome of treatment in advanced cervix carcinoma has been shown to be associated with poor oxygenation of the primary tumour. Hypoxia may cause radiation resistance and promote lymph-node metastasis. The purpose of the study reported here was to investigate whether hypoxia-induced treatment failure in advanced cervix carcinoma is primarily a result of hypoxia-induced radiation resistance or the presence of hypoxia-induced lymph-node metastases at the start of treatment. Thirty-two patients with squamous cell carcinoma of the uterine cervix were included in the study. Radiation therapy was given with curative intent as combined external irradiation and endocavitary brachytherapy. The oxygenation status of the primary tumour was measured prior to treatment using the Eppendorf p O 2 Histograph. Pelvic and para-aortal lymph-node metastases were detected by magnetic resonance imaging at the time of initial diagnosis. The primary tumours of the patients with metastases (n = 18) were significantly more poorly oxygenated than those of the patients without metastases (n = 14). Multivariate Cox regression analyses involving biological and clinical parameters identified the tumour subvolume having p O 2 values below 5mmHg (HSV (p O 2< 5mmHg) as the only significant, independent prognostic factor for locoregional control, disease-free survival and overall survival. The probabillities of locoregional control, disease-free survival and overall survival were significantly lower for the patients with HSV (p O 2< 5 mmHg) above the median value than for those with HSV (p O 2< 5 mmHg) below the median value. On the other hand, the outcome of treatment was not significantly different for the patients with metastases and the patients without metastases at the start of treatment, irrespective of clinical end-point. Consequently, treatment failure was primarily a result of hypoxia-induced radiation resistance rather than hypoxia-induced lymph-node metastasis, suggesting that novel treatment strategies aiming at improving tumour oxygenation or enhancing the radiation sensitivity of hypoxic tumour cells may prove beneficial in attempts to improve the radiation therapy of advanced cervix carcinoma. © 2000 Cancer Research Campaig

Persistent Impairment in Cerebral Vasoreactivity in Subacute Phase Following Concussion

Concussion diagnosis is characterized by a lack of objective markers, as there is a paucity of better understanding of the pathophysiology. Cerebral vasoreactivity (CVR), an important factor in cerebral blood flow (CBF) regulation with dynamic changes in metabolism can be assessed utilizing manipulation of arterial carbon dioxide. CVR utilizing transcranial Doppler ultrasonography may be a useful, objective vascular biomarker for physiological recovery. PURPOSE: To determine the link between clinical symptoms and CVR on Day-3, Day-21, and Day-90 following a concussion in comparison to the non-injured controls. METHODS: Twenty-seven male and female collegiate athletes (21 ±1years) sustaining a sports-related concussion were enrolled. Age and sports-matched non-injured controls were also enrolled. For the concussed athletes, data were obtained on Day-3, Day-21, and Day-90 (N= 17) following the head injury. Symptom severity and cognition were assessed using the Sports Concussion Assessment Tool-3rd Edition (SCAT-3). Depression was assessed utilizing the Patient Health Questionnaire (PHQ-9). Continuous middle cerebral artery blood flow velocity (MCAV) was obtained with transcranial Doppler ultrasonography (TCD) while subjects were seated in an upright position. End-tidal CO₂ (PetCO₂) was measured with an infrared CO₂ analyzer attached to a nasal cannula. MCAV was evaluated in response to changes in PetCO₂ for 2-minutes each during normal breathing (normocapnia), inspiring a gas mixture containing 8% CO₂, 21% oxygen (hypercapnia), and hyperventilating (hypocapnia). RESULTS: On Day-3 subsequent to the head injury, concussed athletes displayed higher symptom number (2.5±3 vs. 12.1±7; PCONCLUSION: Elevated symptoms and lower cognitive scores on Day-3 were resolved by Day-21 following a sports-related concussion. On the other hand, CVR remained impaired at 90 days following concussion suggesting persistent physiological impairment beyond symptom resolution, which could accentuate secondary injuries during this phase. Future studies with a large sample size and longer follow-up period are needed to validate the use of CVR as an objective marker

Profound influence of microarray scanner characteristics on gene expression ratios: analysis and procedure for correction

BACKGROUND: High throughput gene expression data from spotted cDNA microarrays are collected by scanning the signal intensities of the corresponding spots by dedicated fluorescence scanners. The major scanner settings for increasing the spot intensities are the laser power and the voltage of the photomultiplier tube (PMT). It is required that the expression ratios are independent of these settings. We have investigated the relationships between PMT voltage, spot intensities, and expression ratios for different scanners, in order to define an optimal scanning procedure. RESULTS: All scanners showed a limited intensity range from 200 to 50 000 (mean spot intensity), for which the expression ratios were independent of PMT voltage. This usable intensity range was considerably less than the maximum detection range of the PMTs. The use of spot and background intensities outside this range led to errors in the ratios. The errors at high intensities were caused by saturation of pixel intensities within the spots. An algorithm was developed to correct the intensities of these spots, and, hence, extend the upper limit of the usable intensity range. CONCLUSIONS: It is suggested that the PMT voltage should be increased to avoid intensities of the weakest spots below the usable range, allowing the brightest spots to reach the level of saturation. Subsequently, a second set of images should be acquired with a lower PMT setting such that no pixels are in saturation. Reliable data for spots with saturation in the first set of images can easily be extracted from the second set of images by the use of our algorithm. This procedure would lead to an increase in the accuracy of the data and in the number of data points achieved in each experiment compared to traditional procedures

Global MicroRNA Expression Profiling of High-Risk ER+ Breast Cancers from Patients Receiving Adjuvant Tamoxifen Mono-Therapy: A DBCG Study

PURPOSE: Despite the benefits of estrogen receptor (ER)-targeted endocrine therapies in breast cancer, many tumors develop resistance. MicroRNAs (miRNAs) have been suggested as promising biomarkers and we here evaluated whether a miRNA profile could be identified, sub-grouping ER+ breast cancer patients treated with adjuvant Tamoxifen with regards to probability of recurrence. EXPERIMENTAL DESIGN: Global miRNA analysis was performed on 152 ER+ primary tumors from high-risk breast cancer patients with an initial discovery set of 52 patients, followed by two independent test sets (N = 60 and N = 40). All patients had received adjuvant Tamoxifen as mono-therapy (median clinical follow-up: 4.6 years) and half had developed distant recurrence (median time-to-recurrence: 3.5 years). MiRNA expression was examined by unsupervised hierarchical clustering and supervised analysis, including clinical parameters as co-variables. RESULTS: The discovery set identified 10 highly significant miRNAs that discriminated between the patient samples according to outcome. However, the subsequent two independent test sets did not confirm the predictive potential of these miRNAs. A significant correlation was identified between miR-7 and the tumor grade. Investigation of the microRNAs with the most variable expression between patients in different runs yielded a list of 31 microRNAs, eight of which are associated with stem cell characteristics. CONCLUSIONS: Based on the large sample size, our data strongly suggests that there is no single miRNA profile predictive of outcome following adjuvant Tamoxifen treatment in a broad cohort of ER+ breast cancer patients. We identified a sub-group of Tamoxifen-treated breast cancer patients with miRNA-expressing tumors associated with cancer stem cell characteristics

Genome-wide estimation of transcript concentrations from spotted cDNA microarray data

A method providing absolute transcript concentrations from spotted microarray intensity data is presented. Number of transcripts per µg total RNA, mRNA or per cell, are obtained for each gene, enabling comparisons of transcript levels within and between tissues. The method is based on Bayesian statistical modelling incorporating available information about the experiment from target preparation to image analysis, leading to realistically large confidence intervals for estimated concentrations. The method was validated in experiments using transcripts at known concentrations, showing accuracy and reproducibility of estimated concentrations, which were also in excellent agreement with results from quantitative real-time PCR. We determined the concentration for 10 157 genes in cervix cancers and a pool of cancer cell lines and found values in the range of 10(5)–10(10) transcripts per µg total RNA. The precision of our estimates was sufficiently high to detect significant concentration differences between two tumours and between different genes within the same tumour, comparisons that are not possible with standard intensity ratios. Our method can be used to explore the regulation of pathways and to develop individualized therapies, based on absolute transcript concentrations. It can be applied broadly, facilitating the construction of the transcriptome, continuously updating it by integrating future data