An in vitro human skin test for assessing sensitization potential

Sensitization to chemicals resulting in an allergy is an important health issue. The current gold-standard method for identification and characterization of skin-sensitizing chemicals was the mouse local lymph node assay (LLNA). However, for a number of reasons there has been an increasing imperative to develop alternative approaches to hazard identification that do not require the use of animals. Here we describe a human in-vitro skin explant test for identification of sensitization hazards and the assessment of relative skin sensitizing potency. This method measures histological damage in human skin as a readout of the immune response induced by the test material. Using this approach we have measured responses to 44 chemicals including skin sensitizers, pre/pro-haptens, respiratory sensitizers, non-sensitizing chemicals (including skin-irritants) and previously misclassified compounds. Based on comparisons with the LLNA, the skin explant test gave 95% specificity, 95% sensitivity, 95% concordance with a correlation coefficient of 0.9. The same specificity and sensitivity were achieved for comparison of results with published human sensitization data with a correlation coefficient of 0.91. The test also successfully identified nickel sulphate as a human skin sensitizer, which was misclassified as negative in the LLNA. In addition, sensitizers and non-sensitizers identified as positive or negative by the skin explant test have induced high/low T cell proliferation and IFNγ production, respectively. Collectively, the data suggests the human in-vitro skin explant test could provide the basis for a novel approach for characterization of the sensitizing activity as a first step in the risk assessment process.

Osteosarcoma is characterised by reduced expression of markers of osteoclastogenesis and antigen presentation compared with normal bone

Background:

Osteosarcoma (OS) is the most common primary bone tumour in children and adolescents. Patients who respond poorly to chemotherapy have a higher risk of metastatic disease and 5-year survival rates of only 10–20%. Therefore, identifying molecular targets that are specific for OS, or more specifically, metastatic OS, will be critical to the development of new treatment strategies to improve patient outcomes.

Methods:

We performed a transcriptomic analysis of chemo-naive OS biopsies and non-malignant bone biopsies to identify differentially expressed genes specific to OS, which could provide insight into OS biology and chemoresistance.

Results:

Statistical analysis of the OS transcriptomes found differential expression of several metallothionein family members, as well as deregulation of genes involved in antigen presentation. Tumours also exhibited significantly increased expression of ID1 and profound down-regulation of S100A8, highlighting their potential as therapeutic targets for OS. Finally, we found a significant correlation between OS and impaired osteoclastogenesis and antigen-presenting activity. The reduced osteoclastogenesis and antigen-presenting activity were more profound in the chemoresistant OS samples.

Conclusion:

Our results indicate that OS displays gene signatures consistent with decreased antigen-presenting activity, enhanced chemoresistance, and impaired osteoclastogenesis. Moreover, these alterations are more pronounced in chemoresistant OS tumour samples.

Limb salvage for soft-tissue sarcomas of the foot and ankle

We evaluated the oncological and functional outcome of 27 patients who had limb salvage for a soft-tissue sarcoma of the foot or ankle between 1992 and 2007, with a mean follow-up of 7.5 years (1.05 to 16.2). There were 12 men and 15 women, with a mean age at presentation of 47 years (12 to 84). Referrals came from other hospitals for 16 patients who had previous biopsy or unplanned excision, and 11 presented de novo. There were 18 tumours located in the foot and nine around the ankle. Synovial sarcoma was the most frequent histological diagnosis. Excision was performed in all cases, with 16 patients requiring plastic surgical reconstruction with 13 free and three local flaps. Adjuvant treatment was undertaken in 20 patients, 18 with radiotherapy and two by chemotherapy. Limb salvage was successful in 26 of the 27 patients. There have been two local recurrences and two mesenchymal metastases. Four patients have died of their sarcoma and two of other causes.

Function was evaluated with the Toronto Extremity Salvage Score and a mean overall score of 89.40 (52.1 to 100) was obtained. A questionnaire revealed that all surviving patients are able to wear normal shoes and none require a walking aid.

Limb salvage can achieve good oncological and functional results with additional treatment.

Intra-operative implant brachytherapy in the management of soft-tissue sarcomas

BACKGROUND

The management of localized soft-tissue sarcomas remains complex. This is a retrospective review of a single institution experience with manual afterloaded brachytherapy following intra-operative implantation of the tumour bed during surgery.

METHODS

Twelve patients over a 3-year period had resection for localized soft-tissue sarcomas and desmoids with insertion of intra-operative brachytherapy implants combined with resection for localized soft-tissue sarcomas. Manual afterloading of the implant with iridium wires was performed postoperatively in all patients. The low dose rate brachytherapy dose varied from 13 to 20 Gy. Supplementary external beam radiation was administered pre-operatively or postoperatively to bring the total dose of adjuvant irradiation to 60-65 Gy.

RESULTS

After a median follow-up period of 29 months, the 3-year local disease-free survival rate was 63%. The 3-year actuarial survival rate was 83%. There were no failures within the high-dose region of the implant, although two patients had locoregional failures adjacent to the tumour bed at the edge of the radiation field. Three patients developed distant metastases. Side effects were noted in five patients. Wound breakdown and delayed wound healing occurred in two patients. One patient required an amputation as a result of chronic non-healing and wound pain. Pathological fractures occurred in two patients. Those patients who did not develop wound breakdown had good cosmetic and functional outcomes.

CONCLUSION

Intra-operative implantation of the tumour bed in combination with tumour resection for soft-tissue sarcomas results in a high degree of local control with acceptable complications. This modality offers the patient a high chance of avoiding a more radical surgical procedure such as limb amputation.