Abstract
The objective of the current study was to investigate the expression pattern and clinicopathological significance of Period1 (Per1), Period2 (Per2) and Period3 (Per3) in patients with non-small cell lung cancer (NSCLC). In 130 archived NSCLC tissues, the positive rate of Per1 (86/130, 66.2%), Per2 (77/130, 59.2%) and Per3 (82/130, 63.1%) were reduced in human lung cancer samples compared with adjacent normal lung tissues (Per1, 119/130, 91.5%; Per2, 115/130, 88.5%; Per3, 121/130, 93.1%), as measured by immunohistochemical staining. Loss of Per1 was correlated with poor differentiation (P < 0.001), tumor status (P=0.04), high p-TNM stage (P < 0.001) and lymph node metastasis (P=0.045). The similar tendencies were also found in the correlation of the expression of Per2 and Per3 with clinicopathological factors. In addition, a significant correlation was found between Per1 and Per2 (P < 0.001) in 130 cases of NSCLC. Similarly, a significant correlation was found between Per2 and Per3 (P=0.045). Patients with lower expression of Per1, Per2 and Per3 had a shorter survival time than those with higher expression. These results indicate that loss of Per may promote tumor progression in NSCLC, and may serve as a novel prognostic biomarker of NSCLC.