Selective Tyrosine Kinase Inhibitors and The Concept of "Targeted Therapy of Cancer". Will This Be A Real Cure For Cancer?

With the beginning of the 21th century, a new concept of cancer treatment has emerged, which is aimed to block specific tyrosine kinases coupled with growth factor receptors or oncogene products. The discovery of the imatinib/STI-571 (Gleevec, Glivec) and its phenomenal activity in chronic myeloid leukemia fostered a big interest in discovery of selective tyrosine kinase inhibitors and a great hope arouse that the ultimate therapeutics for cancer will be developed in near future. 

Nonetheless, these expectations seem to good to be true, when considering the great plasticity of the cancer cell's transcriptome. Many of the tyrosine kinase inhibitors approved by the FDA for the treatment of solid tumors provide only very limited survival benefits. The main reason of this phenomenon is based on the very fact that the tumor cells do not put their all eggs in one basket. There exist an enourmous alternative of growth factors and apoptosis-blocking proteins , which tumor cells could induce to compensate the noxious effects of anticancer agents targeting only limited signal pathways. Furthermore, these "targeted drugs" are enormously expensive and far from being cost-effective.

Here, a tragedy of self-suffocation exists in our current society. As well known and discussed in many scientific papers and in media, drug companies only interest with patentable molecule sources but not with generic drugs, natural vaccines (such as Coley toxin, which I will discuss later) or phytochemicals, which will not bring "enough" levels of financial benefit for them. This reality leads a vicious cycle to aim discovering more and more "precise targets", yet the cancer's transcriptional defence armamentarium is far more beyond the pharmaceutical companies armamentarium. 

In future - whether the pharmaceutical companies like or dislike- , cocktails of simple drugs targeting many diverse signalling pathways of cancer may provide real cures for cancer. Hereby, I do not try to mention that the discovery of selective tyrosine kinase inhibitors or the concept of "targeted therapy" is worthless. Instead, they may constitute powerful members of the combined anti-cancer cocktails in future. My basic point is not to expect ultimate cures for a devastating disease with single shots and single guns.