Table 1.

Classification of feature sets

Number	Feature Set description	Prior knowledge	Relative to group
Ia	Top 10 most differentially expressed genes	No	No
Ib	All differentially expressed genes	No	No
II	Z-score of differential expression	No	Yes
III	Enriched Gene Ontology terms	Yes	Yes
IV	Significant upstream regulators	Yes	Yes

With respect to (i) their use of prior knowledge independent of the current dataset and (ii) the computation of group-dependent features which will require two feature profiles at test time.