RSPO2 and neoplasm: Given that targeting tumor-derived RSPO2 with monoclonal antibodies effectively retarded the growth of patient-derived xenograft (PDX) tumors, including ovarian tumor (Chartier et al., 2016; Storm et al., 2016), the antibody-based RSPO2 blockage may be a useful adjuvant treatment to improve the outcomes of ovarian cancer patients with high RSPO2 expression.