*2.5. Immunocytochemistry (ICC)*

The cells were fixed with 4% paraformaldehyde and permeabilized with 0.1% Triton X-100 in PBS. Following fixation, cells were incubated at 4 ◦C overnight with anti–CD44 or anti–SOX2 primary antibodies in PBS with 1% BSA and 0.1% Triton X-100. Stained proteins were visualized using secondary antibodies against anti-mouse immunoglobulin/FITC or anti-rabbit immunoglobulin/PE (1:400, BD Bioscience). Nuclei were counterstained with DAPI (Sigma, St. Louis, MO, USA). Following staining, cells were observed with an Olympus IX71 fluorescence microscope (Olympus, Tokyo, Japan).
