Prognostic Value of the Expression of Receptor Tyrosine Kinase-Like Orphan Receptor 1 (ROR-1) in Chronic Lymphocytic Leukemia.

Background: The transmembrane receptor tyrosine kinase-like orphan receptor 1 (ROR1) has acted on the causation and sustentation of mature B-cell lymphomagenesis for chronic lymphocytic leukemia (CLL) cells. The study attempted to show whether there is a relationship between the level of ROR1 surface expression in CLL cells and disease findings. Materials and Methods: The level of ROR1 cell surface expression was determined in accordance with the flow cytometric analysis of CLL patients at the first diagnosis time.  Two groups were formed according to the high and low ROR1 levels. The cut-off point for the ROR1 level was calculated for advanced-stage disease using receiver operating characteristic (ROC) curves. A two-sided p-value <0,05 was considered statistically significant. Results: 108 CLL cases with a median age of 60 were enrolled. The median percentage of ROR1 cell surface marker positivity in the CD5/CD19 positive leukemic cell was 62%. The CLL cases with high ROR1 levels have thrombocytopenia (p=0.042), anemia (p=0.028), and high beta-2 microglobulin value ≥3 mg/dL (p=0.002) and the need for first-line treatment (p=0.043). Conclusion: The poor prognostic parameters such as splenomegaly, anemia, higher beta-2 microglobulin levels, intermediate/advanced RAİ stage disease, and need for first-line treatment had associated high-level ROR 1 expression of our CLL patients. It needs to be investigated for its effect on predicting disease burden and aggressiveness with more comprehensive studies on ROR1 expression levels in CLL cases.