New findings in breast cancer research by an international team of scientists contradict the prevailing belief that only basal-like cells with stem cell qualities can form invasive tumors. Research led by Ole William Petersen at the University of Copenhagen (CU) and Mina Bissell of the Lawrence Berkeley National Laboratory (Berkeley Lab) and has shown that luminal-like cells with no detectable stem cell qualities can generate larger tumors than their basal-like counterparts. This may hold important implications for the diagnosis and the treatment of breast cancer as well as future personalized cancer medicine.
What they discovered was that luminal-like cells without specific basal-like traits were fully capable of initiating tumors in laboratory test mice; in fact, the tumors generated by luminal-like cells were larger than those from basal-like cells. In addition, when tested in an invasion assay, these phenotypically pure luminal-like cells were more invasive than the basal-like cells.
"It demonstrates that basal-like cells, as defined currently, are not a requirement for breast tumor aggressiveness and that within a single tumor there are multiple cells with tumorigenic potential," Bissell says. "This casts doubt on the current hypothesis of hierarchical or differentiative loss of tumorigenicity."