Low expression levels of TP53, highly correlated with deletion and adversely affects outcome. (A) The 194 patients with newly diagnosed MM on TT2 were divided into 2 groups based on TP53 deletion. Kaplan-Meier estimates show 5-year actuarial probabilities of 36% being event-free and 52% alive in cases with TP53 deletion and 51% event-free and 70% alive in those without TP53 deletion (P < .005). (B) TP53 deletion is highly correlated with low TP53 expression. TP53 expression levels, as measured by Affymetrix microarray signal, relative to TP53 copy number by FISH is displayed. Expression levels in 154 cases with no evidence of deletion (minimum, 680; maximum, 5241; median, 1599; mean, 1487) are significantly higher than in 36 cases with monoallelic deletion (minimum, 226; maximum, 2600; median, 889; mean, 1044), which are higher than in 4 cases with biallelic deletion (minimum, 138; maximum, 599; median, 470; mean, 419). (C) Low TP53 gene expression is related to outcome. Samples from 351 patients with newly diagnosed MM on TT2 were divided into 2 groups based on TP53 Affymetrix signal being greater than or less than 733 (lowest 10%). Kaplan-Meier estimates showed 5-year actuarial probabilities of 28% being event-free and 41% alive in cases with TP53 less than 733 and 50% event-free and 68% alive in those with TP53 more than 733 (P < .001).