ATF5 and neoplasm: Co-localized TUNEL and PDGF-B-HA+ tumor marker staining continued to be evident at 64 h after Pen-d/n-ATF5-RP treatment, but the signals indicated cell degeneration and fragmentation (Figure 5E) compared with cells treated with this peptide for 16 h (Figure 5A) or with Pen-Control-RP peptide (Figure 5D).