Additionally, multiple known endocrine hormones, such as insulin, prostaglandins, glucocorticoids, prolactin, and progesterone, have been observed to play a role in cancers by modulating malignant phenotypes or anti-tumor immune responses (Klil-Drori et al., 2017; Wang and DuBois, 2018; Dandawate et al., 2019). Here, PRL is linked to cancer.