CTTN and breast cancer: Kaplan–Meier plots of DMFS in the total population showed significant correlation between poor DMFS and high mRNA levels of ABL2 and CTTN. Strikingly, the combined effect of ABL2 and CTTN overexpression considerably reduced DMFS values with a synergy index (SI) of 1.28, suggesting that Arg and cortactin act synergistically to promote breast cancer metastasis.