Mitochondrial DNA drives tumor dormancy escape in ER+ breast cancer

Although the estrogen receptor (ER) positive variant of breast cancer is touted as the most indolent and favorable, the majority of breast cancer deaths are in fact from this subtype. There are several features of this category of breast cancers that likely account for this outcome. The first is that metastatic relapse can occur many years after initial diagnosis of primary disease. The second is that once the cancer cells awaken into full-blown metastatic disease, they are largely resistant to ER-directed therapies (i.e. hormonal therapy, HT). The third is that when metastases do occur, they are invariably in many locations. This observation suggests that these dormant/sleeping metastatic cells are “globally” awakened as if by a “systemic” infection. We suggest that these three processes be not only linked, but underlie the lethal features of metastatic disease. We hypothesized that mtDNA is necessary for the escape from therapy induced tumor dormancy of luminal breast cancer cells Total RNA was isolated after 2 months of treatment of breast cancer cell lines MCF7 cells with hormonal therapy (tamoxifen, 1uM) and biologically CTRL replicates are also present. Treatments with HT led to tumor dormancy in vitro. Samples for each group were processed for Illumina bead arrays (Illumina HT-12) by the MSKCC genomics core facility according to the specifications of the manufacturer.