Striking and highly significant differences were found between normal kidney and tumor tissue, with high levels in tumor samples of transcripts of HIF target genes SLC2A1 (encoding Glucose transporter GLUT-1), monocarboxylate transporter SLC16A3 (MCT4), CA9, and LDHA, and low levels of LDHB in contrast to matched normal kidney (Fig. 4e). This evidence concerns the gene CA9 and neoplasm.