S100A4 over-expression underlies lymph node metastasis and poor prognosis in colorectal cancer

Figure 1 Identification of quantitatively dysregulated expression of S100A4. A: Quantification of S100A4 through the isotopically labeled fragment ion signals of the peptide “TDEAAFQK”. The areas under the monoisotopic peaks represent the relative abundance of peptides, light [lymph node metastasis (LNM)]/heavy (non-LNM) = 3.04:1; B: Identification of the peptide “TDEAAFQK” from S100A4 by MS/MS.

Figure 2 Confirmation of the overexpression of S100A4 in colorectal cancer. A: Western blotting analysis for S100A4 expression in colorectal cancer (CRC) specimens. β-actin was used as the internal loading control. The histogram shows the relative expression levels of S100A4 in non-LNM (16 cases) and lymph node metastasis (LNM) (16 cases) groups. Data represent the mean ± SE (P < 0.001, Student t test); B: Immunohistochemical study of S100A4 distribution and expression in CRC specimens at 20 × 10 magnification. a: There was no immunoreactivity in the normal mucosa; b: Weak staining in cancer cells in the non-LNM group; c: Strong staining in cancer cells in the LNM group; d: Marked metastatic lymph nodes (arrow); C: mRNA level of S100A4 via real-time quantitative polymerase chain reaction. S100A4 was consistently increased in the LNM group (16 cases) compared with non-LNM group (16 cases). The mRNA level was normalized to that of β-actin. Data represent the mean ± SE (P < 0.001, Student t test).

Figure 3 Overexpression of S100A4 correlated with poor prognosis in 112 colorectal cancer patients. A: Cumulative recurrence between the S100A4-positive and S100A4-negative groups (P < 0.001, log-rank test); B: Cumulative survival between the S100A4-positive and S100A4-negative groups (P < 0.001, log-rank test).