ERBB3 and cancer: Figure 3 depicts the result with Ab4 anti-HER3 rat mAb. Reactivity of Ab4 with unfixed living cells originated from non-epithelial cancers (KNS glioma and several lymphoma/leukemia) and non-cancer tissues (HEK293 embryonic kidney and INT407 fetal intestine) was negative or negligible. However, Ab4 was definitely reactive with human cell lines from various epithelial origins (esophagus, stomach, colon, lung, liver, urinary bladder, breast, uterus et al.).