title: Prognostic relevance of Period1 (Per1) and Period2 (Per2) expression in human gastric cancer.
abstract: Period1 (Per1) and Period2 (Per2) are members of the circadian genes. Mounting evidence suggests that the deregulation of the circadian clock plays an important role in the development of mammalian cancer. However, the expression and clinical significance of Per1 and Per2 in gastric cancer is still unexplored. Here, we evaluated the expression pattern of Per1 and Per2 in 246 gastric cancer specimens and their adjacent, non-tumorous tissues using immunohistochemical assays. Per1 expression was significantly associated with clinical stage (p < 0.001), depth invasion (p < 0.001), lymph node metastasis (p < 0.001) and pathologic differentiation (p < 0.001). On the other hand, Per2 was associated with clinical stage (p = 0.021) and depth invasion (p = 0.007). Per1 expression was positively correlated with Per2 expression in the 246 gastric cancer patients (r = 0.378, p < 0.001), and the expression levels of Per1 and Per2 were down-regulated in gastric cancer tissues when compared with adjacent, non-tumorous tissues in 45 gastric cancer samples (p < 0.001, p = 0.003). Patients with lower Per1 and Per2 tumor expression had a shorter survival time than those with higher expression. Univariate and Multivariate analyses indicated that Per2 expression is an independent prognostic factor (p = 0.023). Our results demonstrate that Per1 and Per2 may play important roles in tumor development, invasion and prognosis, and Per2 may serve as a novel prognostic biomarker of human gastric cancer.
authors.affiliation: Department of The Affiliated Tumor Hospital of Guangzhou Medical University Guangzhou, Guangdong, 510060, China.
authors.forename: Han
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of State Key Laboratory of Oncology in Southern China Guangzhou, Guangdong, 510060, China ; Department of Experimental Research, Sun Yat-sen University Cancer Center Guangzhou, Guangdong, 510060, China.
authors.forename: Zhao-Lei
authors.initials: ZL
authors.lastname: Zeng
authors.affiliation: Department of State Key Laboratory of Oncology in Southern China Guangzhou, Guangdong, 510060, China ; Department of Experimental Research, Sun Yat-sen University Cancer Center Guangzhou, Guangdong, 510060, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Medical Oncology, Sun Yat-sen University Cancer Center Guangzhou, Guangdong, 510060, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Medical Oncology, Sun Yat-sen University Cancer Center Guangzhou, Guangdong, 510060, China.
authors.forename: Miao-Zhen
authors.initials: MZ
authors.lastname: Qiu
authors.affiliation: Department of The Affiliated Tumor Hospital of Guangzhou Medical University Guangzhou, Guangdong, 510060, China.
authors.forename: Xiao-Ye
authors.initials: XY
authors.lastname: Hu
authors.affiliation: Department of The Affiliated Tumor Hospital of Guangzhou Medical University Guangzhou, Guangdong, 510060, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of State Key Laboratory of Oncology in Southern China Guangzhou, Guangdong, 510060, China ; Department of Experimental Research, Sun Yat-sen University Cancer Center Guangzhou, Guangdong, 510060, China.
authors.forename: Kai-Yan
authors.initials: KY
authors.lastname: Liu
authors.affiliation: Department of State Key Laboratory of Oncology in Southern China Guangzhou, Guangdong, 510060, China ; Department of Experimental Research, Sun Yat-sen University Cancer Center Guangzhou, Guangdong, 510060, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Liao
authors.affiliation: Department of Medical Oncology, Sun Yat-sen University Cancer Center Guangzhou, Guangdong, 510060, China.
authors.forename: Rui-Hua
authors.initials: RH
authors.lastname: Xu
authors.affiliation: Department of The Affiliated Tumor Hospital of Guangzhou Medical University Guangzhou, Guangdong, 510060, China.
authors.forename: Qing-Feng
authors.initials: QF
authors.lastname: Zou
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D002454:Cell Differentiation; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D056950:Period Circadian Proteins / Q000032:analysis*; D016016:Proportional Hazards Models; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000401:mortality / Q000473:pathology; D013997:Time Factors; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C539022:PER1 protein, human; C421902:PER2 protein, human; D056950:Period Circadian Proteins
keywords: Circadian clock gene; Per1; Per2; expression; gastric cancer; prognostic