

![0_image_0.png](0_image_0.png)

regardless of the number of trees in the random forest. This is very strong hint that the attributes that were deemed relevant are indeed connected with decision. This is remarkable result when compared with results obtained both with the synthetic and the semi-synthetic data sets, where the non-negligible number of false positives hits were obtained.

Yet the main aim of this experiment was to compare the results obtained with heuristic procedure based on random forests with the previously published lists of important genes. In the original paper Golub et al. reported 50 differentially over-expressed genes (further referred to as Gol1999). Dudoit et al. have reported 91 over-expressed genes (further referred to as Dud2002) and more recently the ranking of 30 genes, based on importance for classification by an ensemble of trees, was reported by Draminski et al. [4] (further referred to as Dram2008).

The data for the latter study was preprocessed differently than that used to obtain Dud2002, and in effect the set of important genes includes two genes which were not present neither in the gene set examined by Dudoit et al. [5]
and in the current work. These genes were excluded from further analysis and