MALAT1 and breast cancer: Given that bone is a frequent metastasis site for breast cancer, we performed intratibial injection of 3-month-old female Malat1+/+, Malat1−/−, and Malat1−/−;Malat1Tg/Tg mice with the EO771 cell line, a cell line derived from a mouse mammary tumor on a C57BL/6 background38.