Pathological and diagnostic implications of DCAF16 expression in human carcinomas including adenocarcinoma, squamous cell carcinoma, and urothelial carcinoma.

DCAF16 is a DDB1-CUL4 associated factor. The expression pattern of DCAF16 in human carcinomas is largely unknown. Here, we investigated DCAF16 expression in a series of human normal epithelial tissues and carcinomas using immunohistochemistry. DCAF16 expression was detected mainly in the cytoplasm in epithelial tissues including thyroid follicles (3/3), epithelium of the prostate glands (2/8), epithelium of the gastric glands (1/2), bronchial epithelium (1/1), epithelium of the intestine (1/1), and hepatocellular epithelium (3/5). There were only 2 cases showing strong immunostaining. Nuclear expression of DCAF16 was detected in a few human carcinomas (0.8%, 9/83). Cytoplasmic DCAF16 expression was detected in human carcinomas including adenocarcinoma (80.0%, 52/65), squamous cell carcinoma (30.8%, 4/13), and urothelial carcinoma (100%, 5/5). The total positive rate of DCAF16 expression was 73.5% (61/83), higher than that in normal tissues (45.8%, 11/24) (P < 0.05). The positive rate of DCAF16 expression in adenocarcinoma (80.0%, 52/65) was higher than that in squamous cell carcinoma (30.8%, 4/13) (P < 0.05). Interestingly, we found that DCAF16 expression in human carcinomas was significantly associated with a higher degree of differentiation (P < 0.05). Our results suggest that DCAF16 is expressed in various human carcinomas including adenocarcinoma, squamous cell carcinoma, and urothelial carcinoma and is not suitable to be used as a diagnostic marker for these cancers. In addition, DCAF16 expression in human carcinomas was elevated compared with that in normal epithelial tissues, suggesting its possible role in oncogenesis. However, the mechanism involved in elevation of DCAF16 expression and its function in human carcinoma needs to be further investigated.