Isolation, characterization and establishment of male breast cancer cells from male breast cancer patient-derived tumor (PDT)

Breast cancer is one of the most common cancers worldwide, but it is more fatal and rarer among men. There are no male patient derived breast cancer cell lines commercially available, limiting research on breast cancers in the male patients. Consequently, most research and therapeutic approaches are largely based on female research subjects because of limited information on male mammary carcinoma. Thus, development of male breast cancer cell lines would provide an excellent biological and preclinical model to study male specific mammary carcinoma. This study aims to establish novel male breast cancer cell lines using tumors derived from male mammary carcinoma patients. Mammary tumors were obtained from three consented male breast cancer patients undergoing mastectomy at the Simmons Cancer Institute. The breast tumor tissues were minced, enzymatically digested overnight at 370c, strained using sterile strainer, and centrifuged to pellet the cells on the following day. The pellets were suspended in HUMEC Ready Mix media and cultured for several weeks until adherent epithelial cells started to grow. The epithelial cell populations were purified by positive flow sorting using EpCAM antibody (epithelial marker) and considered immortal upon reaching passage 20. Out of three tumor samples, two unique male breast cancer cell lines from two different tumor samples have been successfully cultured and named as male breast cancer cell-1(MBCC-1) and male breast cancer cell-2 (MBCC-2). During the flow sorting, MBCC-1, which is currently in passage-50, was noted to be 70% epithelial (EpCAM positive) while MBCC-2 cells, which are currently at passage-19, were 20% EpCAM positive. The average circularity and diameter of the MBCC-1 ranges between 0.6-0.8uM and 12-19 microns while the average population doubling time is forty-two hours. Further, MBCC-1 is capable of anchorage independent growth by soft agar colony formation assay and shows positive expression for Cytokeratin, CD24, CD44, ALDH1, cKIT, ki-67 but is negative for Collagen-IV and fibroblast activation protein (FAP) protein. Studies are ongoing to further characterize both the male breast cancer cell lines, including biomarkers, gene expression profiling, karyotyping, cell proliferation rate, soft agar colony formation assay, nutrient dependency tests, and tumorigenicity assays. In summary, two novel male breast cancer cell lines have been established for studying the biology of male breast cancers.