Chol-siSTAT3 polyplexes (Figure 3A, grey circles) suppressed STAT3 mRNA copy numbers in primary 4T1 breast tumors to a similar extent as Chol-DsiSTAT3 polyplexes (Figure 3A, grey squares) at the highest equimolar dose [47 ± 5 (SD) vs. 46 ± 3%] with a similar half-maximal ED50 [0.2 Chol-siSTAT3 ± 0.1 (SD) vs. 0.3 Chol-DsiSTAT3 ± 0.1 mg/kg] (Figure 3A, dashed line vs. solid line). This evidence concerns the gene STAT3 and breast neoplasm.