Circulating Tumour Cells in Clinical Practice: Can Lessons Learned From Locally Advanced/Metastatic Breast and Prostate Cancers Guide Their use for other Cancer Types? Lights and Shadows

Circulating tumour cells are cells probably involved in different phases of the metastatic process. They can be identified using standardized and repeatable methods and are characterized by EpCAM; Citokeratin 8, 18, 19 and DAPI positivity and CD45 negativity. CTC’s identification in patients with metastatic breast and prostate cancer has been demonstrated to have a prognostic and predictive role. It is not still clear if these cells can be used also in patients with non metastatic breast and prostate cancer, or in patients with different diseases (eg. metastatic and/or locally advanced head and neck cancer) or if they can used to to biologically characterize the disease during its natural history. This review, leaving from the report of the knowledge already consolidated, is devoted to identify the new trends in the research and in the clinical application of CTC, both in locally advanced/localized prostate and breast cancer, and in head and neck cancer.