MKI67 and breast cancer: Luminal B breast cancer has a similar metastatic imaging profile compared to luminal A. As discussed with regard to luminal A subtype, cell proliferation imaging with fluorine-18 fluorothymidine PET can aid in diagnosis of luminal B due to its strong association with Ki-67 (higher uptake would be more indicative of a luminal B tumor rather than luminal A) [27].