Belgian biotechnology company Ablynx said on Monday it has signed a cancer research cooperation accord with US pharmaceuticals giant Merck & Co. which could be worth up to 1.7 billion euros ($2.3 billion). The contract, to identify proteins which may lead to cancer immunotherapy treatments, involves an initial payment of 20 million euros plus 10.7 million euros for the three-year research programme. Subsequent royalties on sales could lead to payment of 1.7 billion euros, Ablynx said in a statement. Merck will be responsible for development, manufacture and say of any treatments generated by the research. Immunotherapy treatments aim to boost the body's own immune response so as to fight cancer.