In a multivariate logistic regression analysis including all exons mutated in ⩾5% of cases (KRAS exons 2 and 3, NRAS exons 2 and 3, TP53 exons 5 and 6, BRAF exons 11 and 15 and CCND1 exon 1), KRAS exon 3 and NRAS exon 3 were significantly associated with the multiple myeloma disease category compared with patients with non-myeloma plasma cell dyscrasias (odds ratio (OR) 9.87, 95% CI 1.07–90.72, P=0.043 and OR 7.03, 95% CI 1.49–33.26, P=0.014, Table 4). This evidence concerns the gene NRAS and plasma cell myeloma.