This is further underlined by the fact that the rule ‘STAT1 high in RA’ appears a total of five times in three different rule sets (rule set ‘Jena’, position 19; rule set ‘Berlin’, positions 1 and 10; rule set ‘Total’, positions 2 and 10; see Table 5 and Additional file 4 for details and the corresponding Affymetrix probe sets). Here, STAT1 is linked to rheumatoid arthritis.