ERBB4 and neoplasm: The L985A and LL783/4AA mutations, which disrupt the tumor suppressor activity of the ErbB4 Q646C EGFP-TVV construct, retain cytoplasmic expression (data not shown), suggesting that ErbB4 trafficking to the cytoplasm is necessary, but not sufficient, for the tumor suppressor activity of the ErbB4 Q646C EGFP-TVV construct.