Cancer Invasion and Metastasis

The major cause of death from cancer is due to the growth of metastases that are resistant to therapy. While surgery can successfully treat primary tumors, the spread of cancer, that is, metastasis, has proven to be a largely insurmountable challenge. Despite almost 200 years of study, the mechanisms and processes involved in tumor progression to metastasis remain controversial. Based on a review of autopsy records, the role of host-tumor interactions was identified leading to the seed and soil hypothesis, which was substantiated a century later. Improving our understanding of the metastatic process and the tumor-cell phenotypes selected by this process is critical to develop successful treatments by the time of diagnosis. One primary challenge in most patients is that metastasis has already occurred prior to diagnosis. Thus, treating systemic disease, as well as identifying patients with early disease, is critical to successful intervention. During the last four decades, metastasis research has made some exciting advances in our understanding of the regulatory mechanisms of metastasis. Nevertheless, some critical aspects remain unclear and require additional, insightful study.