To investigate whether activation of NF‐κB signalling is responsible for tumour cell repopulation stimulated by feeder cells, we applied a dominant‐negative model with the pBabe plasmid and nonphosphorylatable IκBα (pBabe‐IκBα), leading to constitutive suppression of NF‐κB signalling. This evidence concerns the gene NFKBIA and neoplasm.