As reported by Wen and colleagues, in vitro stimulation of PDCD4 expression cannot be accomplished in TNBC when a DNA-hypermethylating agent has been introduced; yet this intervention leads to a positive result in ER+ breast cancer subtype, indicating that TNBC has a hindered expression of PDCD4 that could be pro-tumorigenesis [184]. Here, PDCD4 is linked to breast carcinoma.