Stimulation of MCF-7 tumor progression in athymic nude mice by 17beta-estradiol induces WISP-2/CCN5 expression in xenografts: a novel signaling molecule in hormonal carcinogenesis.

There was 100% solid tumor formation following inoculation of MCF-7 cells. However, MCF-7 tumor progression was significantly greater in the mice exposed to 17beta-estradiol (17beta-E2) compared to unexposed mice. WISP-2/CCN5 mRNA expression was correspondingly increased in 17beta-E2 exposed MCF-7 tumors compared to unexposed xenografts. Moreover, estrogen exposure followed by anti-estrogen tamoxifen treatment drastically inhibited the tumor growth and WISP-2 expression in nude mice. Therefore, the study suggests that higher WISP-2/CCN5 expression by estrogen may be associated with the estrogen-induced growth of MCF-7 tumors in vivo. Finally, overexpression of WISP-2/CCN5 may be considered as a prognostic marker of estrogen-sensitive tumor growth.