Fig. 4

Relative HER4 and HER3 mRNA levels in breast cancer specimen. a HER3- and (b) HER4-high (open circles) and -low (filled circles) expressing tumors were identified using the cutoff algorithm [47]. The differences between high and low HER3 and HER4 expression are significant with p < 0.01 for HER3 and p < 0.001 for HER4