Immunotherapy - applying antibodies against critical molecular targets in tumor cells

Among them you can find some of the most profit-making drugs on earth, like Avastin or Rituxan, selling for around 700 Mio $ each in 2008 (http://www.gene.com/gene/news/press-releases/display.do?method=detail&id=11767). So why are we not done yet? If you look at the websites for Avastin (http://www.avastin.de/) and Rituxan (http://www.rituxan.com/) you encounter the main problem. Avastin for example targets a variety of cancers in breast, lung and kidneys, and in all applicable forms of tumor the target is VEGF, the vascular endothelial growth factor (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=micad&part=Bevacizumab111In). The target for Rituxan is the membrane protein CD20. This explains why Avastin or Rituxan can be applied for different types of tumor and why we are still lacking pharmaceutical agents that target all types of breast cancer or all types of lung cancer. There is no common marker expressed in all types of breast cancer that can be targeted without afflicting serious damage to healthy tissue as well. Antbodies against specific surface molecules on tumor cells is still something to open a business.