ZIP7 (SLC39A7) expression in colorectal cancer and its correlation with clinical prognosis

BACKGROUND: Colorectal cancer (CRC) is a common gastrointestinal malignant tumor that occurs in the colon site and accounts for 9% of the total malignant tumors. Among malignant tumors, its morbidity and mortality respectively rank third and fourth, seriously threatening human health and causing a heavy economic burden on society. ZIP7 (SLC39A7), a kind of zinc transporter, plays a crucial role in the self-renewal of intestinal epithelial cells; however, its role in CRC has not been extensively examined. Therefore, our study aimed to analyze the biological function and expression of this zinc transporter in CRC, along with its correlation with disease activity. METHODS: In this study, 118 cases of colorectal carcinoma tissues, 30 normal tissue samples from adjacent cancer tissues, and 30 normal intestinal mucosa tissue samples from non-intestinal cancer patients were collected in our hospital between February 2014 and February 2015. The expressions of ZIP7 were examined immunohistochemically, and the relationship between ZIP7 expression and the clinical pathological features of CRC were analyzed. After appropriate surgical treatment, the patients accepted a 5-year follow-up for evaluation of their recurrence situation and 5-year survival rate. RESULTS: Immunohistochemically, out of 80 CRC tissue samples, 67.8% were found to be positive for ZIP7, 55% (44 cases) were strong positives, and 45% (36 cases) were weak positives. There was a striking coherence between the expression of ZIP7, the depth of lymph node metastasis, CRC invasion, and CRC Dukes stage (P<0.05). Subsequent studies indicated that the mortality rate was positively correlated with the staining intensity of ZIP7 (P<0.05), and the Cox proportional hazards model confirmed that ZIP7 is an independent element of prognostic in patients with CRC (RR =3.896; 95% CI: 1.526–9.951; P=0.004). CONCLUSIONS: The high expression of ZIP 7 in epithelial cells is related to the clinical stage and prognosis of CRC and can be utilized as a biomarker to predict the prognosis of CRC patients.