ERBB2 and cancer: HER2 expression level did not have a statistically significant correlation with age (p = 0.123), cancer location (p = 0.953), cancer size (p = 0.228), N stage (p = 0.877), TNM stage (p = 0.202), lymphatic invasion (p = 0.357), vascular invasion (p = 0.476), and perineural invasion (p = 0.077).