Figure 2. Alternatively spliced form of FIR (FIRΔexon2) was expressed in ESCC tissues and anti-FIRΔexon2 autoantibodies were detected in the serum of the patients.

(A) The expression levels of FIRΔexon2 and FIR mRNA in esophageal cancer (T) and corresponding non-cancer tissues (N) were examined by qRT-PCR and Western blot. Both FIR and FIRΔexon2 mRNAs were higher in cancer tissue than in non-cancer tissues. (B) The ratio of FIRΔexon2/FIR mRNA expression was higher in esophageal cancer tissues (T: 3.23 in average) than in non-cancer tissues (N: 2.29 in average) without statistical significance (t-test, P=0.221). Note, c-Myc expression showed no significant difference between esophageal cancer and non-cancer tissue examined in this experiment. (C) The degree of expression of FIRs was correlated positively with the number of metastasized lymph nodes. In serum of esophageal cancer patients, anti-FIRΔexon2 autoantibodies were detected compared to FIR. (D) Relative anti-FIR or anti-FIRΔexon2 antibodies detected in the sera of esophageal cancer patients. (E) Anti-FIRΔexon2 autoantibodies, FIRs, and FBW7 expression in cancer tissues. The average of the number of lymph nodes metastasis was significantly smaller in positive cases (N=6, 1.67+1.86) than in negative cases (N=14, 2.29+2.95) in terms of anti-FIRΔexon2 autoantibodies detection. P-values were calculated by Student’s t-test. ^*P<0.05, ^****P<0.0001. Error bars indicated standard error. Esophageal cancer tissue (T) and non-cancer tissues (N) were examined without chemoradiation therapy before operation.