Inflammatory breast cancer (IBC) is a rare form of aggressive breast cancer characterized by the involvement of the skin and the lack of a solid tumor mass. Compared to other breast cancer types, there is little available research concerning risk factors for IBC. However, several studies have indicated that high body mass index (BMI) may contribute to the risk of IBC.
In fact, one study linked high BMI to heightened IBC risk in a linear fashion—the higher the BMI, the higher the risk. Abnormal cholesterol levels have also been found to be associated with increased IBC risk. Now a new study has reported that a high-fat diet increases IBC tumor growth in a mouse model of IBC.
Latest research links high-fat diet to IBC
The study referenced above was designed to investigate the association between a high-fat diet and IBC, taking account weaning status. IBC involves changes caused by tumor emboli (which clog the microvasculature) and changes in breast skin lymphatics. IBC has previously been linked to high BMI and length of breastfeeding.
In the study, the authors modeled the effects of both diet and weaning on aspects of IBC (lymphatic function, mammary gland microenvironment, IBC tumor growth) in mice who were inoculated with IBC (SUM149) tumors. The authors expected that weaning status and diet would have synergistic effects, thereby enhancing IBC tumor growth.
To conduct the study, mice were divided into two groups and fed either a high-fat diet (60 kcal%) or a normal/low-fat diet (10 kcal%) and bred twice (so that they would become multiparous). The mice were then further divided into two nursing groups: normal-duration nursing or forced early weaning. At 14 months, SUM149 IBC tumors were implanted.
Mice on the high-fat diet demonstrated increased pre-tumor lymphatic pulsing in both nursing groups compared to normal/low-fat diet mice. The high-fat diet promoted tumor growth regardless of weaning time. The high-fat diet in nulliparous mice had similar increases in lymphatic pulsing as in multiparous mice, demonstrating that this change was independent of parity.
The authors conclude that the high-fat diet induced increases in mammary gland lymphatic function, which was correlated with inflammation in the mammary gland and higher IBC tumor growth. The authors further conclude that the relationship between diet, lymphatic pulsing, and tumor growth warrants further study.
Please see our article on inflammatory breast cancer and the IBC tag for more information.