EGFR and breast cancer: Age-adjusted linear regressions showed significantly lower levels of S-EGF in women with breast cancer as compared to healthy women (p < 0.001), whereas levels of S-EGFR (p < 0.001), S-HBEGF (p < 0.001), S-AREG (p = 0.002), and S-TGFα (p < 0.001) were significantly higher in women with breast cancer as compared to healthy women.