Wrapper around limma for the comparison of two groups
limmaTwoGroups(object, group)object of class ExpressionSet
string indicating the variable defining the two groups to be compared
topTable output for the second (i.e. slope) coefficient of
the linear model.
Basically, the wrapper combines the lmFit, eBayes and
topTable steps
Smyth, G. K. (2004). Linear models and empirical Bayes methods for assessing differential expression in microarray experiments. Statistical Applications in Genetics and Molecular Biology, Vol. 3, No. 1, Article 3.