It has been shown that upregulated CDKN1A expression regulates cell proliferation in TNBC cells by rescuing the inhibitory effects of liver receptor homolog-1 (LRH-1) in a p53-independent manner [29], which provides the attractive prospect that the CDKN1A/PTN/PTPRZ1 axis could be targeted for the treatment of tumours that are resistant to chemotherapy. This evidence concerns the gene PTN and neoplasm.