Seminal work published by Kwabi-Addu and his coauthors in the Clinical Cancer Research showed that methylation of GSTPi, RARβ2, RASSF1A, NK2 homeobox 5 (NKX-2-5), and estrogen receptor 1 (ESR1) tumours suppressor genes in prostate tissues is age-independent [67]. Here, NKX2-5 is linked to cancer.