Interestingly, since the axis CXCR4/SDF1 has been described as an important element for the apoptosis inhibition mediated by TIMP1, we hypothesize that both TIMP1 and CXCR4 expression in CTCs from ovarian cancer patients could be playing an important role for avoiding apoptosis phenomena. The gene discussed is CXCR4; the disease is ovarian carcinoma.