Human WNT10A and WNT6 were cloned and characterized. WNT10A encoded a 417-amino-acid polypeptide with WNT core domain, and WNT6 encoded a 365-amino-acid polypeptide with N-terminal signal peptide, WNT core domain, and RGD motif. WNT10A and WNT6 genes were clustered in the head-to-tail manner with an interval less than 7.0 kb in human chromosome 2q35 region. Among human WNT family, WNT10A was most homologous to WNT10B (59.2% amino-acid identity), and WNT6 was most homologous to WNT1 (47.4% amino-acid identity). WNT10B and WNT1 genes were also clustered in human chromosome 12q13 region. Two WNT gene clusters in human chromosome 2q35 and 12q13 regions might be generated due to duplication of ancestral gene cluster. The 3.0- and 2.4-kb WNT10A mRNAs were expressed in fetal kidney, placenta, adult spleen and kidney. The 2.0-kb WNT6 mRNA was coexpressed with WNT10A in placenta and adult spleen. WNT10A and WNT6 were strongly coexpressed in SW480 (colorectal cancer). In addition to SW480, WNT10A was strongly expressed in HL-60 (promyelocytic leukemia) and Raji (Burkitt's lymphoma), and WNT6 in HeLa S3 (cervical cancer). Overexpression WNT10A and WNT6 might play key roles in human carcinogenesis through activation of WNT-beta-catenin-TCF signaling pathway, just like Wnt10b and Wnt1.