Gene expression assays in cancer

Some early studies demonstrated the potential of the new technology [39-41] to examine the differences between normal and malignant colonic tissue [39] and identifying potential subclassifications of breast cancer [41]. An interesting aside to these studies was the different analytical methods used by the authors to analyze and interpret the data. This variability of approach remains a feature of microarray studies and can hinder the comparison of data from different studies. However, there are now processes in place which attempt to standardize at least some of the analyses [42], 

It is not possible to review all applications of gene expression arrays in the field of cancer and a number of excellent reviews are available to examine different aspects of the field, for example [43-48]. However, as an introduction to how the methodology has been applied, we will discuss breast cancer as an illustrative example. 

Dissecting Out Tumor Types Using Gene Expression Analysis 

Gene Expression Profiling of Familial Breast Cancer 

It is appropriate to consider some of the general themes that have already become apparent in the short time that microarray technology has been available. Cancer biology is complicated by the mechanisms that can 

---