Furthermore, other CRRGs, such as PPA2, DGAT1, and CABYR, have been shown to be involved in the oncogenic effects of other cancers and to affect patient prognosis, despite the fact that related studies are uncommon in BC (Luo et al., 2007; Cheng et al., 2020; Zhu et al., 2021). Here, PPA2 is linked to breast cancer.