NFKB1 and pulmonary fibrosis: The majority of p-p65 S276 staining was found to locate in the nucleus in fibroblasts and myofibroblasts in MWCNT-exposed lungs (Figures 2A, B), consistent with the activation of NF-κB in fibroblasts and myofibroblasts during MWCNT-induced lung fibrosis development.