A humanized orthotopic tumor microenvironment alters the bone metastatic tropism of prostate cancer cells

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men, and bone is the most frequent site of metastasis. The tumor microenvironment (TME) impacts tumor growth and metastasis, yet the role of the TME in PCa metastasis to bone is not fully understood. We used a tissue-engineered xenograft approach in NOD-scid IL2Rγ^null (NSG) mice to incorporate two levels of humanization; the primary tumor and TME, and the secondary metastatic bone organ. Bioluminescent imaging, histology, and immunohistochemistry were used to study metastasis of human PC-3 and LNCaP PCa cells from the prostate to tissue-engineered bone. Here we show pre-seeding scaffolds with human osteoblasts increases the human cellular and extracellular matrix content of bone constructs, compared to unseeded scaffolds. The humanized prostate TME showed a trend to decrease metastasis of PC-3 PCa cells to the tissue-engineered bone, but did not affect the metastatic potential of PCa cells to the endogenous murine bones or organs. On the other hand, the humanized TME enhanced LNCaP tumor growth and metastasis to humanized and murine bone. Together this demonstrates the importance of the TME in PCa bone tropism, although further investigations are needed to delineate specific roles of the TME components in this context.

Radiation and Androgen Deprivation Therapy With or Without Docetaxel in the Management of Nonmetastatic Unfavorable-Risk Prostate Cancer: A Prospective Randomized Trial

Although docetaxel is not recommended when managing men with unfavorable-risk prostate cancer (PC) given negative or inconclusive results from previous randomized trials, unstudied benefits may exist.

Voxel-based supervised machine learning of peripheral zone prostate cancer using noncontrast multiparametric MRI

Purpose

The aim of this study was to develop and assess the performance of supervised machine learning technique to classify magnetic resonance imaging (MRI) voxels as cancerous or noncancerous using noncontrast multiparametric MRI (mp‐MRI), comprised of T2‐weighted imaging (T2WI), diffusion‐weighted imaging (DWI), and advanced diffusion tensor imaging (DTI) parameters.

Materials and methods

In this work, 191 radiomic features were extracted from mp‐MRI from prostate cancer patients. A comprehensive set of support vector machine (SVM) models for T2WI and mp‐MRI (T2WI + DWI, T2WI + DTI, and T2WI + DWI + DTI) were developed based on novel Bayesian parameters optimization method and validated using leave‐one‐patient‐out approach to eliminate any possible overfitting. The diagnostic performance of each model was evaluated using the area under the receiver operating characteristic curve (AUROC). The average sensitivity, specificity, and accuracy of the models were evaluated using the test data set and the corresponding binary maps generated. Finally, the SVM plus sigmoid function of the models with the highest performance were used to produce cancer probability maps.

Results

The T2WI + DWI + DTI models using the optimal feature subset achieved the best performance in prostate cancer detection, with the average AUROC , sensitivity, specificity, and accuracy of 0.93 ± 0.03, 0.85 ± 0.05, 0.82 ± 0.07, and 0.83 ± 0.04, respectively. The average diagnostic performance of T2WI + DTI models was slightly higher than T2WI + DWI models (+3.52%) using the optimal radiomic features.

Conclusions

Combination of noncontrast mp‐MRI (T2WI, DWI, and DTI) features with the framework of a supervised classification technique and Bayesian optimization method are able to differentiate cancer from noncancer voxels with high accuracy and without administration of contrast agent. The addition of cancer probability maps provides additional functionality for image interpretation, lesion heterogeneity evaluation, and treatment management.

Tumour innervation and neurosignalling in prostate cancer

Prostate cancer progression has been shown to be dependent on the development of autonomic nerves into the tumour microenvironment. Sympathetic nerves activate adrenergic neurosignalling that is necessary in early stages of tumour progression and for initiating an angiogenic switch, whereas parasympathetic nerves activate cholinergic neurosignalling resulting in tumour dissemination and metastasis. The innervation of prostate cancer seems to be initiated by neurotrophic growth factors, such as the precursor to nerve growth factor secreted by tumour cells, and the contribution of brain-derived neural progenitor cells has also been reported. Current experimental, epidemiological and clinical evidence shows the stimulatory effect of tumour innervation and neurosignalling in prostate cancer. Using nerves and neurosignalling could have value in the management of prostate cancer by predicting aggressive disease, treating localized disease through denervation and relieving cancer-associated pain in bone metastases.

Telomere regulation: lessons learnt from mice and men, potential opportunities in horses

Telomeres are genetically conserved nucleoprotein complexes located at the ends of chromosomes that preserve genomic stability. In large mammals, somatic cell telomeres shorten with age, owing to the end replication problem and lack of telomere-lengthening events (e.g. telomerase and ALT activity). Therefore, telomere length reflects cellular replicative reserve and mitotic potential. Environmental insults can accelerate telomere attrition in response to cell division and DNA damage. As such, telomere shortening is considered one of the major hallmarks of ageing. Much effort has been dedicated to understanding the environmental perturbations that accelerate telomere attrition and therapeutic strategies to preserve or extend telomeres. As telomere dynamics seem to reflect cumulative cellular stress, telomere length could serve as a biomarker of animal welfare. The assessment of telomere dynamics (i.e. rate of shortening) in conjunction with telomere-regulating genes and telomerase activity in racehorses could monitor long-term animal health, yet it could also provide some unique opportunities to address particular limitations with the use of other animal models in telomere research. Considering the ongoing efforts to optimise the health and welfare of equine athletes, the purpose of this review is to discuss the potential utility of assessing telomere length in Thoroughbred racehorses. A brief review of telomere biology in large and small mammals will be provided, followed by discussion on the biological implications of telomere length and environmental (e.g. lifestyle) factors that accelerate or attenuate telomere attrition. Finally, the utility of quantifying telomere dynamics in horses will be offered with directions for future research.

Multi-observer contouring of male pelvic anatomy: Highly variable agreement across conventional and emerging structures of interest

INTRODUCTION

This study quantified inter-observer contouring variations for multiple male pelvic structures, many of which are of emerging relevance for prostate cancer radiotherapy progression and toxicity response studies.

METHODS

Five prostate cancer patient datasets (CT and T2-weighted MR) were distributed to 13 observers for contouring. CT structures contoured included the clinical target volume (CTV), seminal vesicles, rectum, colon, bowel bag, bladder and peri-rectal space (PRS). MR contours included CTV, trigone, membranous urethra, penile bulb, neurovascular bundle and multiple pelvic floor muscles. Contouring variations were assessed using the intraclass correlation coefficient (ICC), Dice similarity coefficient (DSC), and multiple additional metrics.

RESULTS

Clinical target volume (CT and MR), bladder, rectum and PRS contours showed excellent inter-observer agreement (median ICC = 0.97; 0.99; 1.00; 0.95; 0.90, DSC = 0.83 ± 0.05; 0.88 ± 0.05; 0.93 ± 0.03; 0.81 ± 0.07; 0.80 ± 0.06, respectively). Seminal vesicle contours were more variable (ICC = 0.75, DSC = 0.73 ± 0.14), while colon and bowel bag contoured volumes were consistent (ICC = 0.97; 0.97), but displayed poor overlap (DSC = 0.58 ± 0.22; 0.67 ± 0.21). Smaller MR structures showed significant inter-observer variations, with poor overlap for trigone, membranous urethra, penile bulb, and left and right neurovascular bundles (DSC = 0.44 ± 0.22; 0.41 ± 0.21; 0.66 ± 0.21; 0.16 ± 0.17; 0.15 ± 0.15). Pelvic floor muscles recorded moderate to strong inter-observer agreement (ICC = 0.50-0.97), although large outlier variations were observed.

CONCLUSIONS

Inter-observer contouring variation was significant for multiple pelvic structures contoured on MR.

Characterization of prostate cancer using diffusion tensor imaging: A new perspective

PURPOSE

This study is aimed at evaluating the potential role of quantitative magnetic resonance diffusion tensor imaging (DTI) and tractography parameters in the detection and characterization of peripheral zone prostate cancer with a particular attention for fiber tract density.

MATERIALS AND METHODS

DTI was acquired from eleven high risk, transrectal ultrasound (TRUS)-guided biopsy proven prostate cancers with perineural invasion (histological Gleason score ≥ 7) on a 3 T magnet. Twenty parameters derived from DTI were quantified in cancer and healthy regions of the prostate. In addition, fiber tract density in normal versus cancer tissues was also calculated using DTI tractography. Support vector machine with a radial basis function kernel and area under receiver operator characteristic (ROC) were used to describe and compare the diagnostic performance of combined fractional anisotropy (FA) and mean diffusivity (MD) and other statistically significant DTI parameters. Spearman correlation analysis between DTI parameters and Gleason scores was conducted.

RESULTS

Eighteen DTI parameters yielded statistically significant differences between cancer and healthy regions (p-value < 0.05). The ROC curve of all statistically significant DTI parameters between cancer and healthy regions was higher than the area under ROC curve using FA + MD alone (95% confidence interval = 0.988, range = 0.975-1.00) vs (95% confidence interval = 0.935, range = 0.898-0.999), respectively (p-value < 0.05). Fiber tract density was also found to be higher in cancer than in healthy tissues (+38.22%, p-value = 0.010) and may be related to the increase in nerve and vascular density reported in prostate cancer. The linear and relative anisotropy were highly correlated with Gleason score (Spearman correlation factor r = 0.655, p-value = 0.001 and r = 0.667, p-value < 0.001, respectively).

CONCLUSIONS

DTI has the potential to provide imaging biomarkers in the detection and characterization of prostate cancer. Novel quantitative parameters derived from DTI and DTI tractography, including fiber tract density, support the use of DTI in the assessment of high grade prostate cancer.

Leukocyte telomere length in the Thoroughbred racehorse

Thoroughbred racehorses possess superior cardiorespiratory fitness levels and are at the pinnacle of athletic performance compared to other breeds of horses. Although equine athletes have undergone years of artificial selection for racing performance, musculoskeletal injuries and illnesses are common and concerns relating to animal welfare have been proposed. Leukocyte telomere length is indicative of biological age, and accelerated telomere shortening occurs with excess physical and psychological stress. This study was designed to explore the association between leukocyte telomere length, biological factors (age, sex and coat colour), training status, winnings and race history parameters. Blood was collected from 146 Thoroughbred racehorses from around Geelong, Victoria, Australia. DNA was extracted from leukocytes; telomere length was measured using qPCR and analysed in context with traits obtained from the Racing Australia website. Age was inversely correlated with telomere length (r = -0.194, P = 0.019). The oldest horses (≥11 years) in the highest age quartile possessed shorter telomeres compared to younger horses in the first, second and third quartiles (≤2, 3-5 and 6-10 years respectively; P < 0.05). No statistically significant associations were observed between telomere length and biological factors, training status, winnings or race history parameters in age-adjusted analyses. The study findings suggest that Thoroughbred horses may undergo age-related telomere shortening similar to other mixed breeds and humans. Despite concerns from some quarters regarding the welfare of racehorses, there was a lack of accelerated biological ageing observed in the present study, as indicated by leukocyte telomere length.

Exercise and epigenetic inheritance of disease risk

Epigenetics is the study of gene expression changes that occur in the absence of altered genotype. Current evidence indicates a role for environmentally induced alterations to epigenetic modifications leading to health and disease changes across multiple generations. This phenomenon is called intergenerational or transgenerational epigenetic inheritance of health or disease. Environmental insults, in the form of toxins, plastics and particular dietary interventions, perturb the epigenetic landscape and influence the health of F1 through to F4 generations in rodents. There is, however, the possibility that healthy lifestyles and environmental factors, such as exercise training, could lead to favourable, heritable epigenetic modifications that augment transcriptional programmes protective of disease, including metabolic dysfunction, heart disease and cancer. The health benefits conferred by regular physical exercise training are unquestionable, yet many of the molecular changes may have heritable health implications for future generations. Similar to other environmental factors, exercise modulates the epigenome of somatic cells and researchers are beginning to study exercise epigenetics in germ cells. The germ cell epigenetic modifications affected by exercise offer a molecular mechanism for the inheritance of health and disease risk. The aims of this review are to: (i) provide an update on the expanding field of exercise epigenetics; (ii) offer an overview of data on intergenerational/transgenerational epigenetic inheritance of disease by environmental insults; (iii) to discuss the potential of exercise-induced intergenerational inheritance of health and disease risk; and finally, outline potential mechanisms and avenues for future work on epigenetic inheritance through exercise.

Wellbeing during Active Surveillance for localised prostate cancer: a systematic review of psychological morbidity and quality of life

BACKGROUND

Active Surveillance (AS) is recommended for the treatment of localised prostate cancer; however this option may be under-used, at least in part because of expectations of psychological adverse events in those offered or accepting AS.

OBJECTIVE

(1) Determine the impact on psychological wellbeing when treated with AS (non-comparative studies). (2) Compare AS with active treatments for the impact on psychological wellbeing (comparative studies).

METHOD

We used the PRISMA guidelines and searched Medline, PsychInfo, EMBASE, CINHAL, Web of Science, Cochrane Library and Scopus for articles published January 2000-2014. Eligible studies reported original quantitative data on any measures of psychological wellbeing.

RESULTS

We identified 34 eligible articles (n=12,497 individuals); 24 observational, eight RCTs, and two other interventional studies. Studies came from North America (16), Europe (14) Australia (3) and North America/Europe (1). A minority (5/34) were rated as high quality. Most (26/34) used validated instruments, whilst a substantial minority (14/34) used watchful waiting or no active treatment rather than Active Surveillance. There was modest evidence of no adverse impact on psychological wellbeing associated with Active Surveillance; and no differences in psychological wellbeing compared to active treatments.

CONCLUSION

Patients can be informed that Active Surveillance involves no greater threat to their psychological wellbeing as part of the informed consent process, and clinicians need not limit access to Active Surveillance based on an expectation of adverse impacts on psychological wellbeing.

Do women have a role in early detection of prostate cancer? - Lessons from a qualitative study

BACKGROUND

Prostate cancer is the most common internal cancer in Australian men; more than 3000 men die annually from it. Public awareness of prostate cancer is an important factor in early detection and treatment. Women are known to act as 'health managers' for their families and may have a role to play in early detection.

OBJECTIVE

To describe community perceptions of prostate cancer and identify information needs within the Australian context.

METHOD

A qualitative study using focus group and individual interviews with 44 community volunteers, 18 men with recent diagnosis of prostate cancer and nine of their wives/partners (n=71).

DISCUSSION

Men in the community are poorly informed about prostate cancer, prefer to ignore (male) health issues, and expect their general practitioners to provide authoritative advice on testing for prostate cancer. While women are also poorly informed, they are keen to change the prevailing situation of silence and lack of information in the community, and need to be included in public education campaigns.

Telling their stories, telling our stories: physicians' experiences with patients who decide to forgo or stop treatment for cancer

There is currently very little research on how physicians respond to patients with cancer who decide to forgo or stop medically recommended "curative" therapy. The purpose of this article is to report on a qualitative study with 12 oncology specialists in Israel and Australia that addresses this question. The findings indicate that physicians tend to construct patients and their decisions in terms of mutually exclusive categories that focus on curability of the disease, rationality of the patient's decision, and patients' personal attributes. Physicians' constructions of their experience focus on uncertainty and concern. Although contextual factors play a role in how physicians act in this situation, Israeli and Australian oncologists are remarkably similar in how they describe their own and their patients' experiences.

Miniature LiF: Mg, Cu, P TLDs to study the effect of applicator material in 192-Ir brachytherapy

Dose calculations in brachytherapy planning typically don't take into account inhomogeneities and the material of applicators. We evaluated the justification of the latter by investigating the dose delivered in 192-Ir interstitial implants employing plastic catheters and steel needles using miniature LiF:Mg,Cu,P thermoluminescence dosimeters (TLDs) which fit in the applicators. Within the uncertainty of the measurement (+/- 5%) no difference could be found in the dose distribution from 192Ir in steel needles or plastic catheters. Computerized treatment planning (Philips/ADAC Pinnacle) was in good agreement with the measured data.

RSV testing in bronchiolitis: which nasal sampling method is best?

Lower nasal swab and higher nasopharyngeal aspirate samples were compared for RSV immunofluorescence and pain score in infants hospitalised with acute bronchiolitis. The nasal swab procedure was significantly less painful but was negative in approximately one third of RSV positive cases.

Tirapazamine, Cisplatin, and Radiation versus Fluorouracil, Cisplatin, and Radiation in patients with locally advanced head and neck cancer: a randomized phase II trial of the Trans-Tasman Radiation Oncology Group (TROG 98.02)

PURPOSE

To select one of two chemoradiotherapy regimens for locally advanced squamous cell carcinoma (SCC) of the head and neck as the experimental arm for the next Trans-Tasman Radiation Oncology Group phase III trial.

PATIENTS AND METHODS

One hundred twenty-two previously untreated patients with stage III/IV SCC of the head and neck were randomized to receive definitive radiotherapy (70 Gy in 7 weeks) concurrently with either cisplatin (75 mg/m(2)) plus tirapazamine (290 mg/m(2)/d) on day 2 of weeks 1, 4, and 7, and tirapazamine alone (160 mg/m(2)/d) on days 1, 3, and 5 of weeks 2 and 3 (TPZ/CIS), or cisplatin (50 mg/m(2)) on day 1 and infusional fluorouracil (360 mg/m(2)/d) on days 1 through 5 of weeks 6 and 7 (chemoboost).

RESULTS

Three-year failure-free survival rates were 55% with TPZ/CIS (95% CI, 39% to 70%) and 44% with chemoboost (95% CI, 30% to 60%; log-rank P = .16). Three-year locoregional failure-free rates were 84% in the TPZ/CIS arm (95% CI, 71% to 92%) and 66% in the chemoboost arm (95% CI, 51% to 79%; P = .069). More febrile neutropenia and grade 3 or 4 late mucous membrane toxicity were observed with TPZ/CIS, while acute skin radiation reaction was more severe and prolonged with chemoboost. Compliance with protocol treatment was satisfactory on both arms.

CONCLUSION

Both regimens are feasible and are associated with significant but acceptable toxicity profiles in the cooperative group setting. Based on the promising efficacy seen in this trial, TPZ/CIS is being evaluated in a large phase III trial.

Tirapazamine, Cisplatin, and Radiation versus Fluorouracil, Cisplatin, and Radiation in patients with locally advanced head and neck cancer: a randomized phase II trial of the Trans-Tasman Radiation Oncology Group (TROG 98.02)

PURPOSE

To select one of two chemoradiotherapy regimens for locally advanced squamous cell carcinoma (SCC) of the head and neck as the experimental arm for the next Trans-Tasman Radiation Oncology Group phase III trial.

PATIENTS AND METHODS

One hundred twenty-two previously untreated patients with stage III/IV SCC of the head and neck were randomized to receive definitive radiotherapy (70 Gy in 7 weeks) concurrently with either cisplatin (75 mg/m(2)) plus tirapazamine (290 mg/m(2)/d) on day 2 of weeks 1, 4, and 7, and tirapazamine alone (160 mg/m(2)/d) on days 1, 3, and 5 of weeks 2 and 3 (TPZ/CIS), or cisplatin (50 mg/m(2)) on day 1 and infusional fluorouracil (360 mg/m(2)/d) on days 1 through 5 of weeks 6 and 7 (chemoboost).

RESULTS

Three-year failure-free survival rates were 55% with TPZ/CIS (95% CI, 39% to 70%) and 44% with chemoboost (95% CI, 30% to 60%; log-rank P = .16). Three-year locoregional failure-free rates were 84% in the TPZ/CIS arm (95% CI, 71% to 92%) and 66% in the chemoboost arm (95% CI, 51% to 79%; P = .069). More febrile neutropenia and grade 3 or 4 late mucous membrane toxicity were observed with TPZ/CIS, while acute skin radiation reaction was more severe and prolonged with chemoboost. Compliance with protocol treatment was satisfactory on both arms.

CONCLUSION

Both regimens are feasible and are associated with significant but acceptable toxicity profiles in the cooperative group setting. Based on the promising efficacy seen in this trial, TPZ/CIS is being evaluated in a large phase III trial.

All delays before radiotherapy risk progression of Merkel cell carcinoma

Prolonged waiting times for radiotherapy have resulted in many centres assigning priorities to various patient or diagnostic groups. A high risk of progression on a waiting list is one factor that would reasonably influence the priority. The present descriptive study of 27 patients with Merkel cell carcinoma (MCC) found that a median wait of 24 days for radiotherapy is associated with a high risk of progression. Eleven (41%) of 27 patients developed progressive disease, including five (45%) of 11 patients waiting for adjuvant radiotherapy. Patients treated adjuvantly also had longer waiting times prior to their initial radiotherapy consultation (median 41 days), which may have contributed to the rate of progression. Merkel cell carcinoma is an aggressive but curable malignancy and appropriate management should include efforts to minimize all potential delays prior to the commencement of radiotherapy.

Dosimetric intercomparison for two Australasian clinical trials using an anthropomorphic phantom

INTRODUCTION

Many different factors can affect the accurate delivery of dose to the clinical target volume in radiotherapy. This is particularly important in the context of multicenter clinical trials where different equipment and techniques may be used for supposedly identical treatments. A dosimetric intercomparison employing an anthropomorphic phantom (level III dosimetric intercomparison) can be used to check many of the factors that could affect treatment by mimicking the radiotherapy pathway of a patient as closely as possible.

METHODS AND MATERIALS

An anthropomorphic phantom (ART) was taken to 18 radiotherapy centers in Australia and New Zealand and treated for two different treatment scenarios based on current clinical trials of the Trans-Tasman Radiation Oncology Group (TROG): a two-field treatment of a carcinoma of the tonsil (TROG 91.01), and a four-field prostate treatment (TROG 96.01). The dose distribution was assessed in two consecutive treatments using thermoluminescence dosimeters (TLDs) placed throughout the target volume and in "critical" structures such as the lens of the eye or the rectum. The study also included a check of absolute dose calibration in a slab phantom (level I dosimetric intercomparison). The influence of a variety of treatment parameters on the dose homogeneity in the target and the measured dose in the target and the critical organs was evaluated.

RESULTS

The dose measurements confirmed that in all participating centers the correct dose was delivered to the ICRU reference point (tonsil: 99.8 +/- 2.3%; prostate: 100.9 +/- 1.9% [1 SD]). Also the absolute dose calibration and the mean dose in the target volume were within the specified action levels of plus minus 5% for all participating centers. No influence of shielding, beam modifiers, beam weighting, treatment planning approach (CT, 2D, 3D), and type of equipment used on the dose in the target and its homogeneity could be demonstrated. However, treatment technique and energy used influenced the dose to the critical organs. It was shown that the interpretation of results could be improved by including two complementary treatment scenarios and a level I intercomparison with the level III dosimetric intercomparison.

CONCLUSION

The study demonstrated the feasibility of a level III dosimetric intercomparison service at a cost of approximately $1000(US) per center in Australasia. It confirmed that the dose delivered by all participating centers was as intended in the two treatment scenarios chosen. While this provides reassurance to the oncology community and the general public, the service must be extended to all centers and other potentially more complex treatment scenarios. The present study has built the foundation for this by establishing a baseline and action levels and suggesting improvements in phantom design which will be included in future TROG quality assurance exercises.

LiF:Mg,Cu,P 'pin worms': miniature detectors for brachytherapy dosimetry

Dose measurements in brachytherapy 192Ir implants are often difficult due to large dose gradients and complex photon spectra. Therefore, tissue-equivalent detectors with a high spatial resolution, such as the highly promising LiF:Mg,Cu,P thermoluminescent detectors (TLDs) are required. It was the aim of the present work to ascertain if miniature LiF:Mg,Cu,P TLDs can effectively measure the dose distribution around 192Ir implants. 'Pin worm' TLDs (type MCP, diameter 0.6 mm, length 2 mm) were compared with GR-200R (SSDL, Beijing) rods cut in half. The TLDs were tested for reproducibility and energy dependence using high dose rate (HDR) and low dose rate (LDR) brachytherapy units. 192Ir measurements were performed in a tissue equivalent phantom accommodating hollow needles and catheters routinely used in brachytherapy. Pin worms had an average reproducibility of less than +/-2% (1 SD) and a detection limit of less than 10 microGy. The small dimensions of the pin worms allowed their placement within brachytherapy needles and catheters. The measured relative dose distribution was in good agreement with the predictions of a computerised treatment planning system (ADAC Pinnacle); however, limitations in the TLD energy correction did not allow for absolute dose comparison.

Enrichment of neurons and neural precursors from human embryonic stem cells

Human embryonic stem (hES) cells proliferate and maintain their pluripotency for over a year in vitro (M. Amit, M. K. Carpenter, M. S. Inokuma, C. P. Chiu, C. P., Harris, M. A. Waknitz, J. Itskovitz-Eldor, and J. A. Thomson. 2000. Dev. Biol. 227: 271-278) and may therefore provide a cell source for cell therapies. hES cells were maintained for over 6 months in vitro (over 100 population doublings) before their ability to differentiate into the neural lineage was evaluated. Differentiation was induced by the formation of embryoid bodies that were subsequently plated onto appropriate substrates in defined medium containing mitogens. These populations contained cells that showed positive immunoreactivity to nestin, polysialylated neural cell adhesion molecule (PS-NCAM) and A2B5. After further maturation, these cells expressed additional neuron-specific antigens (such as MAP-2, synaptophysin, and various neurotransmitters). Calcium imaging demonstrated that these cells responded to neurotransmitter application. Electrophysiological analyses showed that cell membranes contained voltage-dependent channels and that action potentials were triggered by current injection. PS-NCAM and A2B5 immunoselection or culture conditions could be used to produce enriched populations (60-90%) which could be further differentiated into mature neurons. The properties of the hES-derived progenitors and neurons were found to be similar to those of cells derived from primary tissue. These data indicate that hES cells could provide a cell source for the neural progenitor cells and mature neurons for therapeutic and toxicological uses.

Feeder-free growth of undifferentiated human embryonic stem cells

Previous studies have shown that maintenance of undifferentiated human embryonic stem (hES) cells requires culture on mouse embryonic fibroblast (MEF) feeders. Here we demonstrate a successful feeder-free hES culture system in which undifferentiated cells can be maintained for at least 130 population doublings. In this system, hES cells are cultured on Matrigel or laminin in medium conditioned by MEF. The hES cells maintained on feeders or off feeders express integrin alpha6 and beta1, which may form a laminin-specific receptor. The hES cell populations in feeder-free conditions maintained a normal karyotype, stable proliferation rate, and high telomerase activity. Similar to cells cultured on feeders, hES cells maintained under feeder-free conditions expressed OCT-4, hTERT, alkaline phosphatase, and surface markers including SSEA-4, Tra 1-60, and Tra 1-81. In addition, hES cells maintained without direct feeder contact formed teratomas in SCID/beige mice and differentiated in vitro into cells from all three germ layers. Thus, the cells retain fundamental characteristics of hES cells in this culture system and are suitable for scaleup production.

The fanconi anemia proteins FANCA and FANCG stabilize each other and promote the nuclear accumulation of the Fanconi anemia complex

Fanconi anemia (FA) is an autosomal recessive cancer susceptibility syndrome with 8 complementation groups. Four of the FA genes have been cloned, and at least 3 of the encoded proteins, FANCA, FANCC, and FANCG/XRCC9, interact in a multisubunit protein complex. The FANCG protein binds directly to the amino terminal nuclear localization sequence (NLS) of FANCA, suggesting that FANCG plays a role in regulating FANCA nuclear accumulation. In the current study the functional consequences of FANCG/FANCA binding were examined. Correction of an FA-G cell line with the FANCG complementary DNA (cDNA) resulted in FANCA/FANCG binding, prolongation of the cellular half-life of FANCA, and an increase in the nuclear accumulation of the FA protein complex. Similar results were obtained upon correction of an FA-A cell line, with a reciprocal increase in the half-life of FANCG. Patient-derived mutant forms of FANCA, containing an intact NLS sequence but point mutations in the carboxy-terminal leucine zipper region, bound FANCG in the cytoplasm. The mutant forms failed to translocate to the nucleus of transduced cells, thereby suggesting a model of coordinated binding and nuclear translocation. These results demonstrate that the FANCA/FANCG interaction is required to maintain the cellular levels of both proteins. Moreover, at least one function of FANCG and FANCA is to regulate the nuclear accumulation of the FA protein complex. Failure to accumulate the nuclear FA protein complex results in the characteristic spectrum of clinical and cellular abnormalities observed in FA.

Maturation and lineage-specific expression of the coxsackie and adenovirus receptor in hematopoietic cells

Adenovirus vectors have been used to transfer genes into both hematopoietic progenitor cells and tumor cells, including carcinoma cells that have metastasized to bone marrow (BM). However, the relative susceptibility of different subsets of hematopoietic cells is unknown. In permissive cells adenoviral-mediated gene transfer is mediated by the coxsackievirus and adenovirus receptor (CAR) protein and alpha(v) integrins expressed on the cell surface of the target cells. This prompted us to investigate the expression of CAR on subpopulations of hematopoietic cells, determine whether this protein played a role in adenovirus-mediated gene transfer of hematopoietic cells and whether we could modulate CAR to enhance gene transfer efficiency. In this report we show that CAR is expressed on approximately 40% of all human BM cells, including erythroid and myeloid cells, but not lymphoid cells. Of the CD34(+) cells, 10%-15% expressed CAR, but this did not include most colony-forming progenitor cells, nor the most primitive CD38(-) subpopulation. The presence of CAR correlated well with gene transfer efficiency, but we were unable to induce CAR expression on immature, noncommitted progenitor cells. In conclusion, our results show that primitive hematopoietic progenitor cells lack CAR expression, but that expression is acquired during erythroid and myeloid differentiation.

Verification of the dose distribution for 192Ir mould treatments using radiochromic film and LiF:Mg,Cu,P TLDs

Radioactive moulds are an effective way of treating skin lesions. The aim of the study was to verify the dose distribution in a low dose rate 192Ir hand mould treatment using radiochromic film and LiF:Mg,Cu,P TLDs. Measurements were compared with two computerised treatment planning systems--Theraplan VO5B and ADAC Pinnacle3 V4.0b. Radiochromic film measured doses that were typically 25-30% lower than the TLD and planning computer doses (which agreed within +/- 5%). However, radiochromic film provided a two-dimensional map, which is particularly useful for dose distributions that are difficult to predict. This was demonstrated in the effects of adding thumb shielding to the hand mould. TLD results provided only point dose verification. Dose rates to the inner surface of the thumb were reduced from 15-20 cGy/hr to 2-4 cGy/hr by using 7.5 mm lead shielding. This is consistent with three half value layer reductions. For unshielded treatments, TLD results agreed with the treatment planning computers all within +/- 13%, including an uncertainty of +/- 10% on the source strength certificate for the activity. Due to the detector's sensitivity, miniaturisation would be the next approach for further more accurate verification with LiF:Mg,Cu,P TLDs.

A quality assurance audit: phase III trial of maximal androgen deprivation in prostate cancer (TROG 96.01)

In 1997 the Trans-Tasman Radiation Oncology Group (TROG) performed a quality assurance (QA) audit of its phase III randomized clinical trial investigating the effectiveness of different durations of maximal androgen deprivation prior to and during definitive radiation therapy for locally advanced carcinoma of the prostate (TROG 96.01). The audit reviewed a total of 60 cases from 15 centres across Australia and New Zealand. In addition to verification of technical adherence to the protocol, the audit also incorporated a survey of centre planning techniques and a QA time/cost analysis. The present report builds on TROG's first technical audit conducted in 1996 for the phase III accelerated head and neck trial (TROG 91.01) and highlights the significant progress TROG has made in the interim period. The audit provides a strong validation of the results of the 96.01 trial, as well as valuable budgeting and treatment planning information for future trials. Overall improvements were detected in data quality and quantity, and in protocol compliance, with a reduction in the rate of unacceptable protocol violations from 10 to 4%. Audit design, staff education and increased data management resources were identified as the main contributing factors to these improvements. In addition, a budget estimate of $100 per patient has been proposed for conducting similar technical audits. The next major QA project to be undertaken by TROG during the period 1998-1999 is an intercentre dosimetry study. Trial funding and staff education have been targeted as the key major issues essential to the continued success and expansion of TROG's QA programme.

Containment bag for jet lavage irrigation of the foot and ankle

A clear plastic surgical bag which has an incorporated closure string may be used to contain fluid during jet lavage irrigation of foot and ankle wounds. This method may prevent fluid from spraying about, improving barrier precautions for both patient and operating room personnel.

Acute toxicity and cost analysis of a phase III randomized trial of accelerated and conventional radiotherapy for squamous carcinoma of the head and neck: a Trans-Tasman Radiation Oncology Group study

The primary purpose of the present analysis was to assess the feasibility and acute toxicity of a pure accelerated fractionation regimen in a cooperative group setting. This analysis included the first 320 patients entered on to the Trans-Tasman Radiation Oncology Group (TROG) randomized controlled trial which compared accelerated radiotherapy (ART) with conventional radiotherapy (CRT) in stage III and IV squamous cell carcinoma (SCC) of the head and neck. Patients were randomized to either 59.4 Gy in 33 fractions over 24 days (ART) or to 70 Gy 35 fractions over 49 days (CRT) after being stratified for site and stage. Accrual began in 1991 and the trial was closed on 3 April 1998 with the targeted 350 patients. The 3-year survival for the whole group was 54%, and the 3-year disease-free survival was 41%. Toxicity data were available on 303 patients (148 ART; 155 CRT). Mucosal toxicity was worse in the accelerated arm, and it peaked approximately 3 weeks earlier than the conventional arm. Skin toxicity was equivalent but occurred approximately 7 days earlier in the accelerated arm. Acute effects in both arms healed completely. Hospitalization was more common in the ART arm (71 vs 52 patients; P = 0.01) but the total bed days in hospital was not greatly different (1707 bed days for ART and 1607 bed days for CRT). Patients were more likely to require nasogastric (NG) feeding in the ART arm (49 vs 33 patients; P = 0.02). There were 1157 NG feeding days for ART and 1154 NG feeding days for CRT. The average cost of radiation treatment per patient including hospitalization, NG feeding and accommodation was $11,750 in the ART arm and $11,587 in the CRT arm. The accelerated arm has been shown to be a tolerable, practical and cost-equivalent regimen. The assessment of the therapeutic ratio of this accelerated protocol (ART) will be determined when the analysis of late effects and loco-regional control is made when the data are more mature.

Quality assurance audit in an Australasian phase III trial of accelerated radiotherapy for head and neck cancer (TROG 91.01). Trans-Tasman Radiation Oncology Group

The Trans-Tasman Radiation Oncology Group (TROG) initiated a randomized trial, testing accelerated (twice daily) radiotherapy against conventional radiotherapy for stage III and stage IV squamous cell carcinoma of the head and neck in 1991. In 1996, the Trial Management Committee arranged for a technical audit of 76 cases from 11 institutions, conducted by investigators from interstate institutions. A 10% unacceptable protocol violation rate was detected, which compares favourably with initial Radiation Therapy Oncology Group (RTOG) experience in the late 1970s. Infrastructural deficits with poor quality of documentation, incomplete retrieval of films and document return have been demonstrated in some cases. The Trans-Tasman Radiation Oncology Group is actively pursuing procedural and resourcing issues in order to redress this and is actively expanding its Quality Assurance (QA) Programme with an intercentre dosimetry study. Ultimately, comprehensive clinical and technical QA site visits are planned.

Simultaneous adjuvant radiotherapy and chemotherapy for stage I and II breast cancer

The purpose of the present paper was to evaluate treatment outcome after conservative breast surgery or mastectomy followed by simultaneous adjuvant radiotherapy and cyclophosphamide, methotrexate and fluorouracil (CMF) therapy. Two hundred and sixty eight (268) patients were treated at two Australian and two New Zealand centres between 1981 and July 1995. One hundred and sixty-nine patients underwent conservation surgery and 99 had mastectomies. Median follow-up was 53 months. Conventionally fractionated radiation was delivered simultaneously during the first two cycles of CMF, avoiding radiation on the Fridays that the intravenous components of CMF were delivered. In conservatively treated patients, 5-year actuarial rates of any recurrence, distant recurrence and overall survival were 34.5 +/- 5.2%, 25.4 +/- 4.5% and 75.5 +/- 4.8%, respectively. Crude incidence of local relapse at 4 years was 6.3% and at regional/distant sites was 26.3%. Highest grades of granulocyte toxicity (< 0.5 x 10(9)/L), moist desquamation, radiation pneumonitis and persistent breast oedema were recorded in 10.7, 8.5, 8.9 and 17.2%, respectively. In patients treated by mastectomy, 5-year actuarial rates of any recurrence, distant recurrence and overall survival were 59.7 +/- 7.3%, 56.7 +/- 7.4% and 50.1 +/- 7%. The crude incidence of local relapse at 4 years was 5.6% and at regional/distant sites it was 45.7%. The issue of appropriate timing of adjuvant therapies has become particularly important with the increasing acknowledgement of the value of anthracycline-based regimens. For women in lower risk categories (e.g. 1-3 nodes positive or node negative), CMF may offer a potentially better therapy, particularly where breast-conserving surgical techniques have been used. In such cases CMF allows the simultaneous delivery of radiotherapy with the result of optimum local control, without compromise or regional or systemic relapse rates. Further randomized trials that directly address the optimal integration of the two modalities, such as the one carried out in Boston, are clearly necessary.

Variable region domain exchange influences the functional properties of IgG

In the present study we have characterized a family of anti-dansyl Abs with the variable region of the heavy chain on human Ckappa and the variable region of the light chain on different human gamma constant regions (creating inside-out molecules). Although fully assembled molecules were secreted, this variable region exchange slowed the kinetics of Ab assembly. Although the variable region exchange does not lead to a detectable change in the microenvironment of the combining site, it did alter the kinetic parameters of binding to immobilized Ag, slowing both the on and off rates. When effector functions were evaluated, inside-out IgG1 and IgG3 were more effective in complement-mediated cytolysis than their wild-type counterparts. Variable region domain exchange may be one approach to obtaining Abs of identical specificity with altered binding characteristics.

How should we introduce high-dose chemotherapeutic strategies into the adjuvant management of high-risk breast cancer in Australasia?

BACKGROUND

Development of bone marrow support techniques has altered the standard chemotherapeutic management of haematological malignancies, and these techniques are now being increasingly utilized in solid tumours. In breast cancer, survival benefits have resulted from conventional dose adjuvant chemotherapy, but outcomes remain poor in many women with high-risk disease. Improved response rates with high-dose chemotherapy (HDC) in metastatic disease have led to the investigation of these techniques in adjuvant therapy of high-risk localized disease. In some high-risk patient subgroups survival is extremely poor, with 5-year rates below 30%. Improved adjuvant strategies for patients in these subgroups are therefore urgently required. In Australasia, oncology departments are currently considering accrual of women with high-risk disease into the International Breast Cancer Study Group (IBCSG) 15-95 Trial investigating HDC/stem cell transplantation.

METHODS

The present paper reviews the available data on the efficacies and toxicities of currently available high-dose chemotherapeutic strategies; discussing methodological considerations relevant to their introduction and safe use in the adjuvant setting in Australia and New Zealand.

RESULTS

Although response rates with HDC in metastatic disease are encouraging, the clinical effectiveness of current HDC regimens in adjuvant management has not been established and is limited by significant toxicity.

CONCLUSIONS

The introduction of HDC strategies for high-risk breast cancer in Australia encounters difficulties both in trial design and potential clinical practice.

Do inflammatory processes contribute to radiation induced erythema observed in the skin of humans?

BACKGROUND

Two prospective trials were designed to determine whether there may be a role for inflammatory mediators in human skin erythema at both high and low doses per fraction and for 'out of field' effects.

METHODS

Trial 1. Effects of topical indomethacin (1%) and hydrocortisone (1%) applied before and during radiotherapy were compared for erythema induced by 20 Gy in four fractions (n = 26, 6 MV). Trial 2. Effects of topical hydrocortisone (1 %) applied before and during radiotherapy and no medication were compared for erythema induced by 1, 3, 5 and 7 Gy in five fractions (n = 21, 120 kV). Erythema was measured using reflectance spectrophotometry (RFS) and laser Doppler (LD) on a weekly basis.

RESULTS

Trial 1. A bi-phasic reaction time course was suggested in two-thirds of the cases. The first phase did not appear to be influenced by hydrocortisone cream but the second was significantly attenuated. Indomethacin had no effect on either reaction phase. Erythema measured several centimetres outside of the field was reduced by hydrocortisone but not by indomethacin. Trial 2. Trial 2 confirmed the presence of measurable erythema, invisible to the eye, that coincided in its time course to the first phase of erythema noted in trial 1. This reaction was more intense than predicted by the LQ formula and was non-significantly attenuated by topical hydrocortisone. RFS readings proved to be less subject to inter- and intra-patient variations than the LD unit used.

CONCLUSION

Inflammatory responses may play a role in the mediation of the erythematous response to radiation in human skin. Further studies are warranted.

Normal variation in cutaneous blood content and red blood cell velocity in humans

This study was designed to determine normal variations in cutaneous blood content, red blood cell content and skin thickness in healthy human volunteers. The blood content (BC) of human skin and the velocity of red blood cells (RBV) has been comprehensively mapped over 30 anatomical sites in 28 volunteers between the age of 7 and 77 years using reflectance spectrophotometry (RFS) and laser Doppler (LD) techniques respectively. Total skin thickness, which may have a relationship with blood content, has been mapped at the same anatomical sites in six of the volunteers using two-dimensional array, 12 MHz ultrasound equipment. The major determinant of BC and RBV was found to be anatomical site. Regardless of age, gender or prior sun exposure, anatomical sites above the waist produced higher readings than below. BC and RBV were found to be dependent on age and gender at most sites with higher readings being observed in males and younger volunteers. The largest difference was seen in males under 55 years whose RFS readings above the waist were significantly higher than in older males or females of any age. Heavy prior sun exposure and skin thickness could not be demonstrated to impact on either RFS or LD readings independently of the effects of anatomical site, gender or age. In general, RFS and LD readings paralleled one another and correlated linearly at most anatomical sites. While RFS readings tended to decrease in the cranio-caudal direction, LD readings were relatively uniform across the body except for the head and groin where they were higher, and the abdomen where they were lower. The site-to-site variations in RFS readings observed in this study correspond well to capillary density variations noted in previous studies.

TLD extrapolation for skin dose determination in vivo

Prediction of skin reactions requires knowledge of the dose at various depths in the human skin. Using thermoluminescence dosimeters of three different thicknesses, the dose can be extrapolated to the surface and interpolated between the different depths. A TLD holder was designed for these TLD extrapolation measurements on patients during treatment which allowed measurements of entrance and exit skin dose with a day to day variability of +/-7% (S.D. of mean reading). In a pilot study on 18 patients undergoing breast irradiation, it was found that the angle of incidence of the radiation beam is the most significant factor influencing skin entrance dose. In most of these measurements the beam exit dose contributed 50% more to the surface dose than the entrance dose.