Fig. 1

MCL-1 is overexpressed in human esophageal squamous cell carcinoma. a, b Western blot analysis was performed to examine MCL-1, BCL-2 and BCL-xL expression in several ESCC cell lines and normal Het-1A cells. β-actin was used as a loading control (a). The density of each protein was shown (b). The intensity was evaluated using Image J (NIH) computer software. *p < 0.05, **p < 0.01, ***p < 0.001, significant difference compared with the Het-1A cells. c Western blot analysis was performed to examine BAX and BAK expression in several ESCC cell lines. β-actin was used as a loading control. d Representative results of RT-PCR analysis showed Mcl-1 mRNA levels in ESCC tumors (T) compared with normal adjacent epithelia tissues (N). β-actin was used as a loading control (left panel). The levels of Mcl-1 mRNA in malignant and the corresponding normal adjacent tissues of 49 ESCC patients were shown (right panel). The intensity was evaluated using Image J (NIH) computer software. **, p < 0.01, significant difference between groups as indicated. e Representative results of Western blot analysis showed MCL-1 protein levels in malignant tissues (T) and the corresponding normal adjacent tissue samples (N). GAPDH was used as a loading control (left panel). The levels of MCL-1 protein in malignant and the corresponding normal adjacent tissues of 49 ESCC patients were shown (right panel). The intensity was evaluated using Image J (NIH) computer software. *, p < 0.05, significant difference between groups as indicated. f Representative results of immunohistochemistry staining showed up-regulation (cases 2), no significant change (case 18) and down-regulation (case 20) of MCL-1 protein in ESCC tumors (T) compared with the corresponding normal adjacent tissues (N) (original magnification, ×200)