4) Dotan E, Cohen SJ, Alpaugh KR, et al. Circulat-ing tumor cells: evolving evidence and future challenges. Oncologist. 2009; 14: 1070-82.
5) Christiansen JJ, Rajasekaran AK. Reassessing ep-ithelial to mesenchymal transition as a prerequi-site for carcinoma invasion and metastasis. Can-cer Res. 2006; 66: 8319-26.