CCSER1 and cancer: Indeed, overexpression of an isoform isolated from cancer cell lines, lacking a central portion of CCSER1, thus mimicking the situation present in primary tumours (r-CCSER1; Fig S4) was able to increase proliferation in both cancer (HeLa) and immortalized (RPE-hTERT) cell lines (Fig 3A), in line with a recent report (Kang & Park, 2019).