Roles of ZIC family genes in human gastric cancer.

The human zinc finger of the cerebellum (ZIC)family genes, comprised of 5 members, which are vertebrate homologues of the Drosophila odd-paired gene and encode zinc-finger transcription factors, have been shown to be involved in various diseases, including cancer. However, the roles of ZICs in human gastric cancer (GC) have not yet been fully elucidated. This study aimed to investigate the expression patterns of ZICs and determine their clinical significance in GC. The mRNA and protein expression levels of ZIC1-5 were detected by RT-qPCR and western blot analysis, respectively using 60 pairs of human GC and matched normal mucosa tissues. The expression pattern and subcellular localization of ZIC1 in 160 pairs of human GC and matched normal mucosa tissues were verified by immunohistochemistry. Moreover, the associations of ZIC1 expression with various clinicopathological characteristics and patient prognosis were evaluated. The mRNA and protein expression levels of ZIC1 were both found to be significantly decreased in the GC tissues compared to matched normal mucosa tissues (GC vs. normal, 2.15±0.69 vs. 4.28±0.95; P<0.001); however, ZIC2-5 expression exhibited no significant difference between the cancer and normal tissue samples. In addition, the downregulation of ZIC1 (ZIC1-low) was more frequently observed in the GC tissues with positive lymph node metastasis (P=0.006), an advanced TNM stage (P<0.001) and a great depth of invasion (P=0.01). Notably, a low ZIC1 expression was significantly associated with a poor disease-free and overall survival. Furthermore, multivariate analysis revealed that ZIC1 expression was an independent prognostic marker for patients with GC. In conclusion, among the human ZIC family genes, the dysregulation of ZIC1, but not of ZIC2, ZIC3, ZIC4 and ZIC5, may play a crucial role in the progression of GC. ZIC1 may thus serve as a novel molecular marker to predict the progression, survival and relapse of patients with GC.