The Syrian Hamster Embryo (SHE) Low pH Cell Transformation Assay

The Syrian hamster embryonic (SHE) cell transformation assay (CTA) at pH 6.7 can determine the ability of a test article to induce morphological transformation (MT) in cultured SHE cells. The assay uses SHE cells prepared at gestation day ∼13 and frozen. Target cells are seeded onto a layer of feeder cells (X‐ray irradiated SHE cells) and treated with test article for 24 hr or 7 days. After a growth period of 7 days, the cells are fixed, stained, and evaluated for MT. Normal colonies typically contain a monolayer of cells with an organized, often flowing, pattern of growth and minimal cell criss‐crossing at a confluent density. Transformed colonies contain randomly oriented, stacked cells, with cell criss‐crossing throughout the colony. The transformed cells are frequently more basophilic than their normal counterparts, with increased nuclear/cytoplasmic ratios. This assay provides a valuable tool for evaluating the carcinogenic potential of a test article. Curr. Protoc. Toxicol. 35:20.3.1‐20.3.16. © 2008 by John Wiley & Sons, Inc.