The Syrian hamster embryo (SHE) assay (pH 6.7): mechanisms of cell transformation and application of vibrational spectroscopy to objectively score endpoint alterations

Using morphological transformation as an endpoint, the Syrian hamster embryo (SHE) cell transformation assay (pH 6.7) is an in vitro system with a high sensitivity and specificity for testing the carcinogenic potential of test agents. Advantages of the assay are that SHE cells are metabolically competent, genetically stable and acquire spontaneous transformation with a low frequency; additionally, it detects both genotoxic and non-genotoxic carcinogens. However, in comparison with other short-term mammalian cell assays, it is time consuming, laborious and, most importantly, the visual scoring of morphological transformation might be subjective. In this review, we examine the background to the test and why it has the potential for use in safety risk assessment. Additionally, we propose a novel approach to objectively interrogate and classify SHE colonies using vibrational spectroscopy coupled to a mathematical framework for high-throughput screening. It is our view that this alternative approach has the potential to improve the sensitivity and specificity of the in vitro SHE assay.