Although the expression of EGFR mRNA did not positively correlate with the prognosis of human breast cancer patients (Fig 5B, high: n = 974, low: n = 930), high mRNA expression of EGFR significantly correlated with poor prognosis for HER2-positive breast cancer patients (Fig 5C; P = 0.034, high: n = 198, low: n = 22). Here, EGFR is linked to breast cancer.