Researchers at the University of Michigan Comprehensive Cancer Center revealed the genetic basis of phyllodes tumors, a rare type of breast cancer. The findings were published in the journal Molecular Cancer Research and the study entitled “Next-Gen Sequencing Exposes Frequent MED12 Mutations and Actionable Therapeutic Targets in Phyllodes Tumors”.
The team led by Dr. Scott Tomlins, performed a comprehensive analysis using next-generation sequencing techniques in order to identify genetic alterations, from archived tissue samples, that could potentially be responsible for tumor initiation and/or progression. “We know little about the biology of phyllodes tumors. In part, they have not been studied much because it’s difficult to accumulate a large number of samples. Using these new sequencing techniques, we were able to study archived tissue samples, which allowed us to identify enough samples to perform a meaningful analysis”, Dr. Tomlins, study’s senior author, said in a news release.
Phyllodes tumors are rare, accounting for around 1 percent of all types of breast tumors. The majority of these tumors are benign although they retain the potential to become metastatic. Only a few effective treatments are available once phyllodes tumors turn metastatic. There is no reliable method to predict which tumors will recur or spread after the initial treatment.
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The researchers analyzed 15 phyllodes tumors from archived tissue samples at the University of Michigan. Five of the samples were considered benign (not cancerous), five malignant (cancerous) and the remaining five borderline (with characteristics of both). Although it is a small sample size, it can be enough to characterize genetic features of such a rare tumor. The samples were sequenced alongside a set of genes known to play a role in cancer.
The team discovered two genes – EGFR and IGF1R – that were expressed in several malignant phyllodes tumors. Curiously, therapies have already been tested against the proteins encoded by these two genes in other types of cancer. These findings suggest that such therapies could also be tested for phyllodes tumors.
The gene MED12 was also found to be frequently mutated in all the phyllodes tumors analyzed. This gene has been associated with some rare gynecological tumors related to phyllodes tumors, and the team believes it could be linked to tumor initiation.
“Even though phyllodes tumors are rare, it’s important to have good treatment options for the aggressive cases. The first step is understanding the underlying biology of these tumors,” Dr. Tomlins explained. “Further study and validation is needed, but our work has identified several promising targets involved in phyllodes tumors.”