CXCR4 and plasma cell myeloma: In order to investigate the effects of siH19 on hypoxic responses, transcriptional analysis was done on the HIF targets known to be involved in tumor progression and multiple myeloma dissemination: Vascular Endothelial Growth Factor (VEGF), C-X-C chemokine receptor type 4 (CXCR4) and the transcription factors Snail and Slug [19,20,23].