Abstract
Gain of chromosome 1q is a hallmark of breast cancer, and likely reflects oncogene amplification. We previously identified mitotic kinesin KIF14 (kinesin family member 14) as an overexpressed candidate oncogene in the 1q31.3β1q32.1 minimal region of genomic gain in breast cancer cell lines. KIF14 also showed high expression in other cancers, notably an association with survival in lung tumors. We now report KIF14 expression in 99 primary breast tumors and 10 normal breast controls. Measured by realβtime RTβPCR, KIF14 was overexpressed 10βfold on average in tumors relative to normals (t test p = 0.000054); expression increased with grade (ANOVA p = 0.000006). Infiltrating ductal carcinomas had higher KIF14 levels than lobular (p = 0.017), and estrogen receptor (ER) negative tumors had higher KIF14 levels than ER positive tumors (t test p = 0.030). KIF14 expression correlated positively with Kiβ67 mRNA level (Spearman r = 0.692, p = 0.000001), fraction of positive nodes (r = 0.227, p = 0.024) and percent invasive cells (r = 0.360, p = 0.0002), and negatively with percent fatty stroma (r = β0.258, p = 0.010) and percent normal epithelium (r = β0.291, p = 0.003). KIF14 expression is thus tumorβspecific and increased in more aggressive tumors. Indeed, KIF14 expression predicted overall survival (univariate Cox p = 0.010), with an odds ratio of 3.60 (1.37β9.48), in 50 tumors with available outcome data. KIF14 overexpression also predicted decreased diseaseβfree survival (logβrank p = 0.049). These findings are the first evidence of association between expression of a mitotic kinesin and prognostic variables in breast cancer. Β© 2006 WileyβLiss, Inc.