Risk of progression to myeloma or related disorder in 1148 patients with monoclonal gammopathy of undetermined significance. (A) The upper curve illustrates risk of progression of all patients without taking into account competing causes of death. The lower curve illustrates risk of progression after accounting for other competing causes of death. (B) The upper curve illustrates risk of progression of monoclonal gammopathy of undetermined significance in patients with an abnormal serum kappa-lambda FLC ratio (< 0.26 or > 1.65). The lower curve illustrates the risk of progression in patients with a normal ratio.