Fig. 4

Flow cytometry evaluation of TK1 expression on the surface of colorectal patient tissue. Healthy normal and malignant colon tissue was dissociated into a single cell suspension solution and stained with anti-TK1 antibody 91651, isotype control, anti-CD44 (positive control), and anti-NFkB (negative control). Unstained cells were also used as a negative control. a Flow cytometry histograms showing normal and malignant colon tissue stained with isotype control (gray area) and anti-TK1 antibody ab91651 (black line). There is a definitive shift in fluorescence in the malignant cells treated with ab91651, whereas there is no shift in fluorescence in the normal colon cells treated with the same antibody. b Quantification and analysis of flow cytometry data on the expression of TK1 on the surface of normal and malignant colon. Malignant colon tissues show a significantly higher expression of TK1 on their membrane compared to normal colon tissues (P = 0.002). Normal colon tissues show comparable results to those of the isotype control (P = 0.8004), suggesting TK1 expression on the surface of normal colon tissues is negligible