TNBC-TICs produce significantly more metastatic foci than TNBC, TPBC-TICs, TPBC or parental 4T1 cells. Female BALB/c mice (6-8 weeks old) were injected with 104 parental 4T1 cells (4T1wt), triangles), TPBC, TPBC-TICs, TNBC or TNBC-TICs into the left breast pad. Twenty-one days post tumor cell implantation animals were euthanized and lungs filled with a solution of India Ink (1:6 in PBS) via intratracheal route. Bars represent the mean number of lung metastatic foci (102 × SEM) and are the sum of three independently performed experiments with five mice per group. *p < 0.001 vs parental 4T1 cells (4T1wt).