The actin-binding protein LCP1 is usually expressed in hematopoietic cells and participates in the immune response of hematopoietic cells.24 However, the LCP1 protein is often ectopically expressed in nonhematopoietic malignant cancer cells and is considered a marker of cancer progression.9,25–27 In particular, LCP1 phosphorylation at Ser5 has been shown to be important for the immune response of leukocytes and the invasion and migration of cancer cells.27 In this study, we found for the first time that LCP1 is overexpressed in olaparib-resistant ovarian cancer cells. The gene discussed is LCP1; the disease is ovarian cancer.