ERBB4 and neoplasm: Cohen et al. have shown that a clone of NIH3T3 cells transfected to co-express EGFR and HER2 shows higher levels of tumor-forming abilities in nude mice than other conditions (EGFR, HER2, HER3, HER4, EGFR+ HER3+, EGFR+ HER4+, and HER2+ HER3+) [5].