The purpose of the in vitro Chromosome Aberration (CAB) Assay is to evaluate a compound, or its metabolites, for the ability to induce chromosome aberrations in cultured mammalian somatic cells. The CAB Assay is an in vitro mammalian cell genotoxicity test, which evaluates the carcinogenic potential of a compound. It is designed to evaluate the effect of the parent chemical, as well as its metabolites, by the addition of a liver enzyme mixture. Mitotic index, or cytotoxicity, is used to select cultures which are stressed by the presence of the compound prior to scoring for chromosome aberrations. Chinese Hamster Ovary (CHO) cells are used as the cell line. The cell growth is arrested during metaphase to allow the chromosome evaluation.
Note: A mini-CAB test (Non-GLP) is offered with CHO cells as a four hr plus metabolic activation tests and is commonly used to allow sponsors to select between compounds for development. Because a positive¬Ýresult is most likely to occur in the 4 hr +S9 portion of the study, this is the only portion of the test that is performed in the mini-CAB; thus, this screening assay offers the opportunity for quicker turn-around to study completion, lower cost for early phase compound selection and less compound required for analysis versus a full CAB Assay.
