As a regulator of coagulation, abnormal Protein Z (PZ) expression may lead to the formation of blood clots in humans. While previous studies have shown that PZ protein is altered in several types of cancer, however, additional observations are needed to understand the complex biology involved. Herein, we investigated local alterations in PZ expression in lung adenocarcinomas by measuring gene and protein expression in both cancerous and normal lung tissues. Twenty-two (22) specimens of lung adenocarcinoma and 22 specimens of normal lung tissues from human patients were compared for the expression of PZ. In addition, A549 adenocarcinoma cells were compared to a normal epithelial cell line, 16-HBE, for in vitro PZ expression. In tissues and cells, PZ protein and gene expression were determined using western blot, immunohistochemistry and PCR. Lung adenocarcinoma tissues showed elevated expression of both PZ mRNA and protein compared with healthy tissue. Only protein expression was increased in cultured cell lines, which holds implications for the dominant source of PZ in tissues, as well as protein modifications necessary for PZ function. Protein Z appears to be associated with the presence of lung adenocarcinoma and may be a viable prognostic biomarker for lung cancer.
Keywords: 16-HBE; A549; Lung adenocarcinoma; PZI; Protein Z.