IntroductionEarly diagnosis offers the best hope many have of beating cancer. Unfortunately, this is not the end of the fight for many cancer patients. Primary tumors can be successfully treated at an early stage, only to find that they have metastasized to other parts of the body. The common medical definition of metastasis is: The spread of cancer from one part of the body to another. Tumors formed from cells that have spread are called "secondary tumors" and contain cells that resemble those of the original (primary) tumor. This definition could be the reason why early treatment of a primary tumor is ineffective against metastatic tumor cells. As the definition suggests, the accepted model for tumor cell metastasis is based on clonal evolution, in which secondary tumors have genomes similar to those of the primary tumor. Recent studies, however, suggest that this may not be accurate. A significant divergence between primary and secondary tumors in renal cell metastases and breast metastases has been found in recent studies. An alternative model, of parallel evolution, would explain why therapies targeting primary tumors fail against metastatic cells. Further research into this alternative model could lead to therapies targeting not only the properties of the primary tumor but also those of secondary tumors. tumor and save many people from the burden of fighting cancer.MethodsThis study included 386 breast cancer patients and divided them into two groups. M0, patients with cells without metastases, and M1 patients, those with metastases and performed genomic analysis, or comparative genomic hybridization (CGH) of cytokeratin...... middle of paper ...... tumor cells that could potentially spread, mutate, change and develop into another tumor. More emphasis should be placed on the development of disseminated cells, because changes in their growth cannot be reflected by genomic data obtained from primary tumor data; therefore, they cannot be treated the same. The main idea of ​​this study is to highlight: "the need to validate potential cellular targets for adjuvant and systemic therapies directly on disseminated cancer cells" (Cancer Cell: July 2003). The article under discussion is: Gray, JW, Evidence is emerging for early metastases and parallel evolution of primary and metastatic tumors. Cancer Cell July 2003. Schmidt-Kittler, O. et al., From disseminated latent cells to overt metastases: genetic analysis of systemic progression of breast cancer. PNAS 100, 7734 (2003).