Comparison of genes and pathways commonly dysregulated in both endometrium and myometrium of women with versus without adenomyosis revealed a role for prolactin (PRL) signalling, supporting a longstanding hypotheses for involvement of PRL and PRLR in the pathogenesis and pathophysiology of this disorder (Mori et al., 1981). The gene discussed is PRLR; the disease is adenomyosis.