Effect of JAK2 SNP rs2274472 on outcome for mCRC patients treated with first-line FOLFIRI and bevacizumab: Data from FIRE-3 trial.

595Background: The Jak2 (Janus kinase 2) / Stat5a (signal transduction and activators of transcription 5a) pathway plays a key role in regulating cell survival, proliferation and immune function. JAK2 is a non-receptor tyrosine kinase which is stimulated by a variety of cytokines. Moreover the JAK2 / STAT5 axis is activated by hypoxia and involved in regulating angiogenesis. We therefore hypothesize that variations in the JAK2 gene may predict outcome in patients with metastatic colorectal cancer (mCRC) treated with first-line FOLFIRI and bevacizumab (bev). Methods: Theimpact of 2 functional SNPs within the JAK2 and STAT5a genes on outcome was evaluated in 295 pts with mCRC treated with first-line FOLFIRI / bev in the randomized phase III FIRE-3 trial. 227 pts receiving FOLFIRI and cetuximab (FIRE-3) served as a negative control. Genomic DNA was extracted from formalin fixed paraffin embedded tissue and the SNPs were analyzed by PCR-based direct sequencing. Results: Baseline characteristics in the FOLFIRI...