The exciting use of cDNA microarrays to reveal molecular subclasses of human tumors has spread to the study of animal models that mimic human tumors. With unsuspected subclasses of human lymphomas, melanomas, colon carcinomas, and breast carcinomas uncovered, researchers naturally have been inspired to apply microarray analysis to animal tumor models that in some instances have been studied for decades. How closely, they wonder, will experimental tumors resemble human tumors in details of gene expression?
Complete answers will take years, if for no other reason than the extraordinary number of models investigators need to examine. For breast cancer alone there are at least 100 different mouse mammary tumor models, says Jeffrey E. Green, head of the Transgenic Carcinogenesis Group at the National Cancer Institute (NCI). Green, Richard Simon, chief of NCI's Biometric Research Branch, and their colleagues recently published the first analysis of gene expression profiles of mouse mammary tumors.1
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