High-fat diets promote colon orthotopic transplantation tumor metastasis in BALB/c mice.

High-fat diets (HFDs) are a risk factor for colorectal cancer. The present study investigated whether HFDs increase colon cancer metastasis in BALB/c mice. A total of 40 BALB/c mice were divided into four groups, including the tumor, tumor-HFD, HFD and control groups. After 3 weeks, the tumor weights and metastases were observed. The serum levels of triglyceride, total cholesterol, lapin, interleukin-6 (IL-6) and tumor necrosis factor were analyzed using ELISA. The CD34, vascular endothelial growth factor (VEGF) and angiotensin 2 (ANG2) protein and mRNA levels in tumor tissues were analyzed with immunohistochemistry and reverse transcription-polymerase chain reaction. The metastasis frequency increased in the tumor-HFD group. However, there was no difference in the mean tumor weight between the tumor-HFD and tumor groups. The serum cholesterol levels were increased in the tumor-HFD and HFD groups compared with the control group. The levels of serum IL-6 and tumor necrosis factor-α were increased in the tumor-HFD group compared with other groups. The CD34 protein level, and VEGF protein and mRNA levels were increased in the tumor-HFD group compared with the tumor group. No difference was identified between the ANG2 protein and mRNA levels in of the two groups. It was concluded that HFD increased the serum level of cholesterol and cytokines, and potentially induced tumor angiogenesis, promoting transplanted orthotopic colon tumor metastasis in BALB/c mice.