Association of zinc transporter expression with clinicopathological features and prognosis in patients with breast cancer.

Zinc transporters, including ZIP6 (SLC39A6, also known as LIV-1) and ZIP10 (SLC39A10), are reportedly involved in breast cancer progression and metastasis. We aimed to clarify the association of the expression of zinc transporters with clinicopathological features and prognosis in breast cancer. We retrospectively included 200 patients who underwent surgery for invasive ductal carcinoma of the breast (invasive diameter ≥ 10 mm) at our institution between January 1, 2010 and June 30, 2023. Immunohistochemical staining for ZIP6 and ZIP10 was performed, and their expression levels were evaluated. Survival analyses were performed by stratifying patients into four groups based on combined ZIP6 and ZIP10 expression (high/low). We found that the expression levels of ZIP6 and ZIP10 showed a statistically significant positive correlation. Low ZIP6 expression was associated with aggressive clinicopathological features, including a higher Ki-67 labeling index, higher histological grade, and larger tumor size. Although survival differences did not reach statistical significance, combined evaluation of ZIP6 and ZIP10 expression revealed distinct survival tendencies among the expression groups. These findings suggest that combined assessment of ZIP6 and ZIP10 expression may provide additional prognostic information beyond ZIP6 expression alone. Future studies with larger cohorts and longer follow-up are warranted to validate these findings.