MKI67 and infection: Staining for vimentin and EpCAM demonstrated that most HER2+ cells in the lungs of Il6-KO:MMTV-Her2 mice retain vimentin expression and maintain EpCAM-negative status, which together with the failure to enter the cell cycle, as shown through immunofluorescence for Ki67, supports an IL-6 requirement for infection-induced DCC conversion from dormancy to awakening (Fig. 3e,f).