SOX transcription factors with high-mobility-group DNA-binding domain (HMG box) play key roles in embryogenesis. Some members of the SOX family are negative regulators of the WNT-beta-catenin-TCF signaling pathway. We have previously cloned and characterized human SOX17, constituting a subfamily with SOX7 and SOX18. Another group mapped SOX7 gene to human chromosome 8p22, and reported almost ubiquitous expression of 5.0-kb SOX7 mRNA in human normal tissues. Here, expression of SOX7 mRNA was investigated by using SOX7 specific probe, which hybridized to 3.8-kb human SOX7 mRNA, but not to 5.0-kb mRNA. SOX7 mRNA was relatively highly expressed in adult lung, trachea, lymph node, placenta, fetal lung, and heart. In adult heart, SOX7 mRNA was more highly expressed in ventricules, inter-ventricular septum and apex than in atriums. SOX7 mRNA was significantly up-regulated in pancreatic cancer cell lines BxPC-3, PSN-1, Hs766T, and in 4 cases out of 8 cases of primary gastric cancer. SOX7 mRNA was relatively highly expressed in a gastric cancer cell line MKN45, esophageal cancer cell lines TE2, TE3, TE4, TE5, TE7, TE8, TE11, TE12, and TE13. On the other hand, SOX7 mRNA was significantly down-regulated in 7 out of 18 cases of primary colorectal tumors, in 4 out of 9 cases of primary breast cancer, in 4 out of 14 cases of primary kidney tumors, and also in some cases of primary lung and prostate cancer. SOX7 gene might be one of cancer-associated genes on human chromosome 8p22.