Ras mutational status is a biomarker for resistance to EGFR inhibitors in colorectal carcinoma.

The epidermal growth factor receptor (EGFR) has been validated as a therapeutic target in several human tumours, including colorectal cancer (CRC). Although EGFR expression is used for patient selection, clinical experience shows that levels of EGFR expression (measured by immunohistochemistry) do not predict clinical benefit. Ras mutations in codons 12, 13 and 61 (found in 40-45% of CRC cases) result in inhibition of GTPase activity, thus leading to the constitutive activation of the ras proteins, which may render tumour cells independent of EGFR signalling and thereby, resistant to cetuximab, panitumumab and EGFR TKIs.

Brivanib, a novel dual VEGF-R2/bFGF-R inhibitor.

The process of neo-vascularisation from pre-existing blood vessels (angiogenesis) plays a critical role in both tumour growth and dissemination in multiple cancer types. Tumour angiogenesis is an attractive target for cancer treatment, and the VEGF/VEGF-R and FGF/FGF-R systems have been identified as key factors for neo-angiogenesis. Several active compounds have been developed so far and some of them are already widely used in clinical protocols.