To clarify the mechanism by which CXCR4 modulates the proliferation rate of ovarian cancer cells, we next analyzed the viability of stable CXCR4-shRNA#1, #2-mediated knockdown-OVCAR420 (CXCR4-Kd#1/OVCAR420; CXCR4-Kd#2/OVCAR420) and CXCR4-overexpressing SKOV3 (CXCR4/SKOV3) cell lines after treatment with paclitaxel (PTX) at 0.01 to 1000 nM for 48 hours by the MTT assay. Here, CXCR4 is linked to ovarian cancer.