IRAK2 and breast cancer: In search of the upstream molecular events of NF-κB signalling that might be aberrantly expressed in breast cancers, we interrogated The Cancer Genome Altas database and found that IRAK1, a known upstream regulator of NF-κB, is significantly overexpressed in various subtypes of breast tumours in comparison with normal breast epithelium (Fig. 1a, P<0.0001, Tukey's multiple comparisons test), whereas the other three members of the IRAK family IRAK2-4 did not show such a difference (Fig. 1a).