IL6 and B-cell chronic lymphocytic leukemia: Previous studies have identified significant elevations of serum IL-6 levels in patients who develop various diseases, such as rheumatoid arthritis; Crohn’s disease; and some types of cancer, such as lymphomas, chronic lymphocytic leukemias, prostate cancer, breast cancer, gastric cancer, and neuroblastoma [50,51,52,53,54].