Klf activation following growth factor inhibition in human cancer.

We measured total gene expression in the primary tumors of humans treated with the vascular endothelial growth factor alpha (VEGF-A) inhibitor bevacizumab (Avastin) to describe the tumor transcriptional landscape in response to growth factor restriction and to identify genes that mediate the compensatory, feedback responses that define the general growth factor inhibition resistance gene signature. We report here activation of the Kruppel-lke factor KLF4 in the primary tumors of humans treated bevacizumab. Pluripotency and embryonic growth factor requirements are mechanistically linked here in the primary transcriptional response to VEGF-A inhibition in vivo.