Breast cancer metastasis driven by ErbB2 and 14-3-3zeta: A division of labor.

Metastasis remains the leading cause of cancer morbidity and mortality. ErbB2, a metastasis-promoting oncoprotein, is overexpressed in 50-60% of noninvasive ductal carcinoma in situ (DCIS). However, only 25% of invasive breast cancer (IBC) overexpress ErbB2, indicating that ErbB2 alone is not sufficient to drive metastasis and additional risk factors are necessary for the progression of ErbB2-overexpressing DCIS to IBC. A recent study published in Cancer Cell identified 14-3-3xi as a risk factor aiding the transition of ErbB2-overexpressing DCIS into IBC. Furthermore, the study elucidated molecular mechanisms by which ErbB2 and 14-3-3xi co-overexpression drives metastasis. Namely, ErbB2 promotes cell motility and migration via the activation of Src, while 14-3-3xi induces epithelial-mesenchymal transition by activating TGFbeta pathway to reduce cell adhesion. On the other hand, two studies recently published in British Journal of Cancer and Oncogene provide mechanistic insight into how ErbB2 signalling is transduced via Src, focal adhesion kinase and Ste20-like kinase to regulate focal adhesion turnover and modulate cell motility and migration. Taken together, these studies reveal that metastasis engages a variety of players that must show team spirit to win the game of spreading.