ROR1 and B-cell chronic lymphocytic leukemia: Although CLL cells have the morphological characteristics of mature B lymphocytes, they frequently over-express Wnt pathway genes associated with pro-B or pre-B cells, including Wnt3, Wnt16, the orphan Wnt receptor ROR1, and the LEF-1 transcription factor [10], [11], [12], [30], [31].