Efficacy of anti-cancer agents in cell lines versus human primary tumour tissue

The discovery of anti-cancer drugs has become dependent on cell lines, which are used to screen potential compounds for activity as well as to explore cancer biology. Cell lines produce rapid results, but their relevance to patient outcomes is questionable as they undergo selection over many passages to a point where they are no longer representative of their originating tumour. This has led to the increasing use of primary cell cultures, primary tumour cell explants, early passage cell lines, and xenografts to improve the accuracy of results during drug development. Over the last few years, there has been an increasing interest in these methods and they are now firmly established, with a plethora of different techniques available. For instance, explant and three-dimensional models allow cell:cell interactions to be examined in live cells, and endpoints can include the measurement of gene expression and image analysis. In the future, anti-cancer drug development is likely to use a combination of molecular, cell line, primary or early passage cell culture, and xenograft methods for lead optimisation before clinical trials are contemplated.