The R-ISS scores were according to the expected [46], although a bit higher proportion (30%) of our participants had R-ISS 3, which probably reflects that our cohort is population based and thereby included more patients with high Beta-2-microglobulin due to renal insufficiency than are observed in randomized clinical trials, because these patients do not fulfil inclusion/exclusion criteria [46]. Here, B2M is linked to Renal insufficiency.