IL1B and breast carcinoma: Besides the autocrine mechanism of breast-cancer derived IL-1β in driving the cancer cell bone-seeking behavior, it was observed that MDA-MB-231 cells migrated to and colonized human bone tissue-conditioned medium that contained high levels of IL-1β, which indicates that IL-1β derived from the bone tissue microenvironment may also support the osteotropic breast cancer cell behavior [44].