Background:

Colorectal cancer (CRC) is one of the most common cancers in Japan. Many factors influence this cancer, one of which is circadian rhythm disruption. Our research investigated the correlation between singlenucleotide polymorphisms (SNPs) in the Period 3 (PER3) (rs2640908), which is one of the circadian genes, and colorectal cancer in the Japanese population.

Methods:

The study participants consisted of 121 cases and 197 controls. DNA was extracted from participants’ peripheral blood cells, and polymerase chain reaction—restriction fragment length polymorphism analysis (PCRRFLP) was performed to detect genotypes of PER3.

Results:

Participants with T/T genotype were at lower risk of developing colorectal cancer than participants with C/C genotype (adjusted ORs = 0.32 (95% CI: 0.15–0.63)). When stratified by gender and smoking status, T/T genotype were associated with a decreased susceptibility to cancer in males only (adjusted ORs: 0.23 (95% CI: 0.09–0.59)), T/T genotype were also associated with a decreased susceptibility to cancer among both smokers and non-smokers.

Conclusions:

A significant association was found between the T allele of PER3 polymorphism and a reduced risk of colorectal cancer, especially in males. Smoking status showed no association with the relationship between PER3 genotype and CRC carcinogenesis (AU)