To screen appropriate cell lines for further experiments, we performed protein immunoassays to determine NPC1L1 levels in six cell types: cervical cancer cell line (Hela), colon cancer cell line (Caco-2), human osteosarcoma cells (U-2OS), human pancreatic cancer cells (SW1990), human breast cancer cell line (MCF-7), and liver cancer cell line (HepG2). Here, NPC1L1 is linked to breast cancer.