A study led by Sendurai Mani, Ph.D., associate professor of Translational Molecular Pathology at MD Anderson, and Jeffrey Chang, Ph.D., assistant professor of Integrative Biology at The University of Texas Health Science Center at Houston, found that tumors resembling six-day-old mouse embryos are more prone to metastasize than those that look like tissues from adult mice. Specifically, the researchers noticed that the same genes that are turned on in developing mice are also present in metastatic tumors.
“Looking at the embryo to learn more about cancer is a novel and important finding for researchers,” said Mani. “It is difficult to predict metastasis by merely analyzing the primary tumor and often, no mutations can be found. Clinicians still need to know whether a tumor is going to metastasize.”
For cancer cells to metastasize, they must change their characteristics. In the primary tumor, cancer cells must grow quickly before they stop growing and enter a “migratory state” where they disseminate to the metastatic site. To establish tumor spread, they need to switch back to a fast-growing cell. Scientists call this ability to change characteristics “plasticity.”
Mani’s team wondered if tumors likely to spread would behave like embryos, in particular, early stage embryos.
“During early stages of embryo development, this phenomenon of plasticity is more prevalent compared to that in embryos at later stages or even in adult tissues, and our findings clearly demonstrate that metastatic tumors bear remarkable similarities in gene expression profiles to that of mouse embryos at day 6.5 of early gestation,” said Mani.
“Our findings clearly demonstrated that metastatic tumors are more like the embryo,” he said. “We found that tumors having gene expression signatures similar to mouse embryonic development day 6.5 were more prone to develop metastasis compared to tumors with more adult-differentiated signatures.”