Figure 1

SAV1 is downregulated in RCC with copy number loss at 14q22.1. a Positive correlation of copy number with the expression ratio (R = 0.8871) of the SAV1 gene in RCC cell lines (786-O, 769-P, KMRC-1, KMRC-2, KMRC-3, KMRC-20, TUHR4TKB, and Caki-2). Log₂ ratio of the normalized relative signal intensity of SAV1 by microarray (Y-axis) and log₂ ratio of the gene copy number (X-axis) are plotted for each cell line. R, Pearson correlation coefficient. p-values were calculated by t test. b Correlation of the expression level with copy number loss of SAV1 mRNA at 14q. Quantitative RT-PCR was performed for ccRCC cases that had been analyzed by array CGH in our previous study [7]. On the basis of gene copy number ratio, ccRCC cases were divided into two groups [cases without 14q loss; log₂ ratio -0.14 to 0.15 (n = 10), and cases with 14q loss; log₂ ratio < -0.14 (n = 12)] and analyzed for their expression of SAV1. The box plots show the log₂ ratio of SAV1 mRNA normalized by the median value for 6 samples of normal kidney (Normal). SAV1 mRNA levels are significantly lower in cases with 14q loss than in those without, and normal kidney (p < 0.005). The Y-axis displays the expression level (log₂). P values were calculated by the Mann-Whitney U-test. *p < 0.005. Vertical lines in each column indicate mean ratio, and bars show s.d.. c Correlation of the expression level of SAV1 mRNA with tumor grade. The box plots show log₂ ratio of SAV1 mRNA normalized by the median value for 6 samples of normal kidney. SAV1 mRNA levels are significantly lower in high-grade ccRCC tissue than in low-grade ccRCC and normal kidney (p < 0.005).