The mouse lymphoma assay.

In this paper, the current status of the protocol for the Mouse Lymphoma Assay is discussed. A brief history describes the events leading to current protocol recommendations. Areas for further development such as cytotoxicity, 24-h treatments, acceptability criteria and statistical analysis are also considered. Recent guidelines are reviewed, and consensus issues from the Mouse Lymphoma workgroup assembled as part of the International Workshop on Genotoxicity Test Procedures (IWGTP) are included. There are two versions of the assay - soft agar and microwell - and both will be discussed. For assay procedures, the emphasis will be on a typical microwell protocol but an attempt will be made to highlight protocol variations between laboratories and between the microwell and agar versions of the assay.