In 2015, Pomila Singh and her colleagues further used cancer stem cell (CSC) markers (e.g., doublecortin-like kinase 1 (DCLK1) and leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5)) with epithelial cell markers (CD44 and ANXA2) to detect circulating CSCs in patients with malignant colon adenocarcinomas. Here, DCLK1 is linked to cancer.