ERBB4 and neoplasm: For example, at the same cut-off value of ≥5% of tumour cells with positive immunostaining, the expression of wtEGFR was accompanied by co-expression with HER2 (35%), HER4 (30%), EGFRvIII (36), CD44 (44%), CD109 (4%), and HER2/HER4 (29%), respectively (Table 3).