HSPB1 and colon carcinoma: However, in U937 human leukemic cells, MEF cells, macrophages (Salari et al., 2013) and rat colon carcinoma REG cells, HSPB1 appears to enhance NF-κB activation in response to either etoposide or TNF-α treatment (Parcellier et al., 2003), suggesting that the outcome of NF-κB regulation by HSPB1 may vary with cell type or stimuli.