Research on circadian clock genes in common abdominal malignant tumors

ABSTRACT

Circadian rhythm describes the 24-h oscillation in physiology and behavior of living organisms and presents a timing controller for life activity. Studies in recent years have reported that the abnormal expression of clock genes is closely related to the development of common abdominal malignant tumors. The expression of the 14 kinds of clock genes in 6 abdominal malignant tumors from Cancer Genome Atlas (TCGA) data was integrated and analyzed using R and Perl programming languages to show the association between clock gene expression and prognosis of cancer patients. Analysis of TCGA data indicated that the overexpression of Per1-3, Cry2, CLOCK, NR1D2 and RORA with underexpression of Timeless and NPAS2 was associated with a favorable prognosis in kidney cancer. In liver cancer, high expressions of Cry2 and RORA were correlated with prolonged overall survival (OS) in patients, while high expressions of NPAS2 and Timeless were correlated with a poor survival. High expression of CLOCK was positively correlated with OS in colon cancer patients. High expression of Cry2 and low expression of DEC1 were associated with a favorable prognosis in pancreatic cancer patients, respectively. Most of these clock-genes expressions were closely related to the clinical stage and degree of tumor differentiation of patients. Aberrant clock gene expression is related to the biological characteristics of abdominal malignant tumors, which likely has a causal role in cancer development and survival.

KEYWORDS:

• Circadian clock
• abdominal malignant tumor
• prognosis

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

This study was supported by the National Natural Science Foundation of China: [Grant Number 81702885], the Research Project of Hubei Provincial Science and Technology Department: [Grant Number 2017CFB178], the Fundamental Research Funds for the Central Universities: the Independent Innovation Fund of Huazhong University of Science and Technology: [Grant Number HUST: 2016YXMS241], Chinese Foundation for Hepatitis Prevention and Control “Tian Qing” Liver Research Fund: [Grant Number TQGB20170005].