The expression pattern of H0XC10, H0XC11, H0XD10, and H0XD11 in the human endometrium through the menstrual cycle differs from that of HOXA10 and H0XA11, both of which rise dramatically in the mid-luteal phase. Whereas H0XA10 and H0XA11 are regulators of endometrial receptivity, HOXC and HOXD genes may have a role in the early development of endometrium and endometrial proliferation rather than in differentiation and receptivity to embryonic implantation. A network of HOX genes may be involved in regulating multiple aspects of endometrial development, including both proliferation and differentiation.
Although HOX gene expression has been classically associated with differentiation, recent studies have suggested a role in proliferation. At the start of cell division, proteins must be assembled onto replication origins to establish competence for initiation of DNA synthesis. The selection and activation of these replication origins is the key process in controlling chromosome replication during cell proliferation. H0XC10 protein binds a 74-bp sequence within the human DNA replication origin associated with the Lamin B2 gene in Cos7 cells. Additionally, H0XC10 is highly expressed in two exponentially growing cell lines, namely HeLa S3 cells and monocytic U937 cells.