Breast cancer is one of the leading causes of death epidemiologically. Typically, it is the result of a mutation which may cause a change within the molecular mechanisms employed by the cells to survive. Any changes in these mechanisms have the potential to lead to division at a high rate. It can then lead to formation of masses in the breast. When such masses lack the ability to spread, they are called benign. Similarly, if they have the ability to invade, they are called metastatic. Our goal for this study is to explore the role of gene SPANXB1 (Sperm Protein Associated with Nucleus in Chromosome X) in metastasis of cancer. It has been reported to be present in melanoma and carcinoma of breast, lung, colon, and ovary. In the first aim of our study, we have observed higher SPANXB1 expression in cancer tissues and metastatic lymph node than in normal breast tissue. In the second aim of our study, we have expressed the SPANXB1 protein in MCF7 cells that are known to be so growing cancer cells, in addition we have also expressed this gene in non-cancerous HMLE cells. We found that both MCF7 and HMLE cells gain an increase in their invasion ability when SPANXB1 is expressed more, comparing to their native state where SPANXB1 is expressed less.