CYP19A1 and neoplasm: However, similar to ER PR data, the IL-6 data suggest that tamoxifen and aromatase inhibitors would likely target the largest tumor BCSC population represented by CD49f−CD24−(MM), but not the scarce stem/progenitor populations represented by CD49f+CD24+(PP), CD49f+CD24−(PM) or CD49f−CD24+(MP) cells.