BIRC2 and plasma cell myeloma: We found that half of Myeloma XI tumors carried a deletion of NFκB-pathway genes, and 10% of tumors had two co-occuring deletions.23, 24, 25 Intriguingly, our data suggests NFκB-inducing kinase (NIK)-specific addiction of the t(4;14) group: BIRC2/BIRC3 deletions, including homozygous deletions, were enriched in t(4;14) tumours.