SPAG9 and breast cancer: Studies on SPAG9 also showed that it is associated with cellular proliferation, migration and invasion of cancer cells [18–21], and is capable of eliciting humoral immune responses in a majority of epithelial ovarian cancers (67%) [13], breast cancers (80%) [16], cervical cancers (80%) [17], renal cell carcinoma (77%) [14], colorectal cancer (74%) [15] and hepatocellular carcinoma [22].