FC-IBC-02: A New in vitro-in vivo Model of Triple Negative Inflammatory Breast Cancer

Inflammatory breast cancer (IBC) is the most aggressive type of advanced breast cancer and is associated with a poor prognosis. We have developed a new model of IBC derivated from the pleural effusion of a 49-year-old woman with metastatic secondary IBC. FC-IBC02 tumor cells were isolated from the pleural effusion and cultured under non-adherent conditions, resulting in the formation of spheroids or mammospheres. FC-IBC02 are triple negative (estrogen receptor negative, progesterone receptor negative and ErbB2 negative) and strongly positive for E-cadherin, beta-catenin and vimentin. FC-IBC02 cells developed breast tumors when they were injected into the mammary fat pad of SCID mice and characteristic tumor emboli were detected. Breast tumor xenografts were poorly differentiated triple negative carcinomas and all injected mice developed metastasis in the lungs and lymph nodes. These IBC tumor cells showed genomic alterations in all chromosomes, with the gains/amplifications more common than the deletions/losses. Duplicated regions were on 1q, 2p, 3q, 8q and 18p and chromosomes 7 and 9. The 8q chromosome arm where the MYC oncogene resides was amplified up to seven fold. Chromothripsis (local chromosome shattering) was observed on chromosome 11q and losses were found on 8p, 11q, 16q and 17p (location of TP53). FC-IBC-02 cells expressed the stem cell marker CD44, EpCAM and strongly expressed EGFR and ALK. In summary, this novel preclinical model demonstrated that IBC is a disease enriched for highly tumorigenic cells which harbor a stem cell phenotype. This IBC model is ideal for the study of the metastatic process and to evaluate targeting therapeutic modalities. Total RNA were isolated from IBC-02, IBC-02 in mammosphere growth, IBC3, SUM149, SUM190, MDA-MB231, and MDA-MB468 cell lines. Affymetrix Human U133 Plus 2.0 arrays were used for whole-genome gene expression assays. Duplicate samples were analyzed for each cell line.