Breast cancer is the most common malignancy amongst women and developing new strategies for treating metastatic cancer and preventing metastasis altogether is a crucial step in decreasing breast cancer mortality. A recent project led by Zelei Yang, a doctoral student at the University of Alberta, looks at the connection between a particular infection and the process of metastasis in mouse models.
Yang recently published a paper in the journal Cancers outlining the findings of the project entitled "Latent Cytomegalovirus Infection in Female Mice Increases Breast Cancer Metastasis." She is a member in the labs of CRINA co-director Dr. David Brindley and CRINA member Dr. Denise Hemmings. Yang received a partial stipend from the Cancer Research Institute of Northern Alberta (CRINA), thanks to the Roses of Hope Foundation, a charitable organization backed by La Vie En Rose and its clients in support of women's health.
As Yang's paper outlines, once breast tumors metastasize, the 87% 5-year survival rate drops to just 22%. Yang's project was sparked by the discovery of a surprising statistic - while cytomegalovirus (CMV) infects anywhere between 40 and 70% of women, it infects 95% of breast cancer patients. Yang investigated the finding by infecting mice with either mCMV (mice cytomegalovirus) or a negative control medium for particular spans of time (4 days, 11 days, or 10 weeks) to establish active, intermediate or latent infections. She then gathered data by examining tumor mass, type (single, multi-lobed, small fused), blood content and collagen content.
The findings reveal interesting data about the role of cytomegalovirus infection in metastasis. The infection didn't affect tumor growth, or the number and size of breast tumors. However, an increased amount of tumors were multi-lobed with decreased collagen content and greater blood content. Greater blood content and blood vessels in tumors suggests greater angiogenesis, which would promote metastasis. The lower collagen content in the tumors indicated the cancer cells are more easily able to escape the primary site, another factor that supports increased metastasis. The mCMV infection increased the number and size of lung metastasis in particular, demonstrating that a latent mCMV infection increases metastasis to the lungs.
Increased metastasis is prognostic of decreased survival, so the results of the study raise the possibility that preventing hCMV (human cytomegalovirus) infections or treating the effects of hCMV infections could potentially decrease metastasis and increase the life expectancy of breast cancer patients.
Zelei Yang has always been passionate about making a difference through cancer research. "The rate of cancer has increased a lot in recent decades, especially for breast cancer, which I'm most interested in as a female," said Yang.
However, the interdisciplinary nature of the project was one of the major reasons Yang was interested in this project specifically. "It's a virology and also immunology," said Yang. "Instead of just looking at cancer, I wanted something that was incorporating other departments, I thought that was more interesting than just looking at a specific oncogene." CRINA facilitates collaborations between members within different fields that may potentially lead to impactful discoveries in the field of cancer research.