RSPO2 and ovarian cancer: To determine the specificity of RSPO2 on tumor growth, we next screened two siRNAs (siRS2-1# and siRS2-2#) that can effectively target RSPO2 in two ovarian cancer cell lines, and then used the most effective interference sequence siRS2-2# to construct the lentiviral vector (shRS2) (Figures S1C and S1D).