ERBB2 and breast cancer: However, when breast cancer patients were considered as two different groups based on HER2 expression, the comparison revealed that HER2- patients carried significantly lower amounts of IL-2 (P = 0.0222), IL-8 (P = 0.009), and IL-6 (P = 0.016) with respect to donors (Figure 4), whereas the cytokine profile of HER2+ cases was almost superimposable to that of healthy women (Figure 4).