TLR9 and breast cancer: Therefore, the major questions of this study were: (1) How does cell free rDNA content change in cancer; (2) What type of response in the MCF7 breast cancer cells is caused by TR-rDNA; and (3) What type of DNA sensors (TLR9 or AIM2) is stimulated in MCF7 in response to the action of TR-rDNA?