Upregulation of SHP2 expression correlates with the migratory and invasive ability of oral cancer cells. (A) Oral tumors and histologically normal oral mucosa adjacent to the tumors were stained with anti-SHP2 antibody. The IHC semi-quantitative score was derived by two independent pathologies, multiplying the staining intensity by the percent of tumor cells stained. IHC scores for each core of a specimen were averaged (n = 19) and statistically analyzed. (B) cDNA from paired oral tumor samples were subjected to RT-PCR (n = 18). Relative expression of SHP2 transcript to internal control gene, GAPDH was calculated as described in Materials and Methods. (C) Cell proliferation was performed by MTT assay. Cells were counted at 570 nm wavelength and the relative absorbance was represented as mean ± SD from at least four independent experiments. (D) Cells were seeded onto the transwell chamber coated with matrigel as described in Methods. Images are representative of cells adhering to the lower chamber after the invasive process. Cells were stained with crystal violet solution, and images were taken by photography (Upper panel). Invading cells per file on the lower chamber were counted. The data are expressed as mean ± SD from three independent experiments; P < 0.05. (Lower panel) (E) An increased SHP2 transcript level was associated with higher invasive ability of HSC3 cells. The expression of SHP2 for HSC3-Inv4 and HSC3-Inv8 was normalized to HSC3 parental cells.