Next, we evaluated the levels of CLPTM1L and cancer stem cell markers in a panel of high-grade serous ovarian carcinoma (HGSOC), ovarian cystadenocarcinoma, and endometrioid ovarian cancer cell lines and found that CLPTM1L is expressed highly in cisplatin resistant ovarian tumor cells PeO4, OVCAR5-CisR, HeyA8-CisR, A2780-CisR, and MCW-OV-SL3-CisR compared to their parent cells (Fig. 2a) along with increased expression of c-KIT, and CD44 and a reduction in CD24, which are features of ovarian cancer stem cells (Supplementary Fig. 2a). This evidence concerns the gene CLPTM1L and ovarian serous carcinoma.