Figure 1. (A) Up- and downregulation of cdk5 expression in human cancers. Analysis of cdk5 expression in cancer vs corresponding normal tissues was performed using the Oncomine microarray online data mining software with threshold p value < 0.05; fold change = all; gene rank = all; data type = mRNA.11,12 Out of 308 independent data analyses of 137 microarray data sets, consisting of a total of 12,902 patients, 146 analyses showed upregulated and 41 analyses showed downregulated expression of cdk5 compared with normal tissues. In the “other” category, cancers with upregulated cdk5 expression include uterine and parathyroid cancers, while cancers with downregulated cdk5 expression include testicular and skin cancers. *Note that several multicancer data sets were separately analyzed for different cancer types and, thus, the total number of data sets analyzed (137) does not match with the actual cumulative number of data sets (149). (B) Survival of relapsed multiple myeloma patients following bortezomib treatment is linked to cdk5 expression. Kaplan-Meier survival analyses show that patients with cdk5 expression in the highest quartile have significantly reduced survival relative to patients with cdk5 expression in the lowest quartile (p = 0.0021; n = 42).12 Bortezomib treatment (1.3 mg/m2) was performed on days 1, 2, 8 and 11 for eight 3-week cycles followed by three 5-week cycles with bortezomib administered on days 1, 8, 15 and 22. No significant difference was observed in the dexamethasone-treated group (p = 0.4891, n = 18; data not shown).