Expression profiles of 10 members of Frizzled gene family in human gastric cancer.

Frizzled (FZD) genes encode seven-transmembrane type WNT receptors, which are implicated in carcinogenesis and embryogenesis. We have previously cloned and characterized FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, and FZD10. Here, we investigated expression profiles of all members of the FZD gene family in human gastric cancer. FZD mRNAs were detected by one-step cDNA-PCR. Specificity of cDNA-PCR was confirmed by nucleotide sequence analyses of cDNA-PCR products. Among seven gastric cancer cell lines, FZD7 was up-regulated in MKN7, which was consistent with a previous report. FZD5 was up-regulated in MKN45. FZD9 and FZD10 were up-regulated together in TMK1 and MKN74. FZD2 was up-regulated in TMK1, MKN7, MKN28, MKN45, MKN74 and KATO-III. Among 10 cases of primary gastric cancer, FZD9 was up-regulated in 2 cases, FZD2 and FZD8 were up-regulated in 4 cases. Effects of Helicobacter pylori (H. pylori) on expression of FZDs were further investigated, and it was revealed that FZDs were not up-regulated by H. pylori in MKN45 cells. These results indicate that FZD2, FZD8, and FZD9 might play key roles in human gastric cancer.