Thursday, April 5, 2012

This "Magic Bullet" is Critical for Future Cancer Treatment

Bright future ahead for antibody cancer therapy
March 15, 2012 in CancerAntibodies, once touted as the "magic bullets" of cancer care, are now fulfilling that promise and more advances are on the way, say cancer researchers at the Georgetown Lombardi Comprehensive Cancer Center

When we think of antibodies we typically think of an immune response. The reference here is different and is an excellent example of how molecular biology can provide insights that revolutionize clinical treatment.
The news article demonstrates how these types of antibodies, monoclonal antibodies, can prevent a signalling cascade that prevents immunological activity in tumours. Monoclonal antibodies are simply molecules designed to have the right shape in order to induce a change in a particular molecular activity. Monoclonal antibodies always held great promise and we are beginning to see that find clinical value. As the news articles notes, some of our most successful breast cancer drugs a mAbs. 
An ongoing mystery about immunological surveillance of tumours was the apparent identification of the tumour as being dangerous but a lack of response. This "recognition but fail to act" aspect of immunological responses has long baffled us but this research beautifully elucidates the underlying pathways and how we can challenge these to fight cancer. 
This study indicates that in relation some melanoma cancers this inhibition of the immune response is mediated by a specific receptor and the mAb prevents its activation. Thus ... 
A good example of the new class of antibody-based therapies is , a drug approved in 2011 to treat patients with metastatic melanoma, says Weiner. Ipilimumab is a fully  which binds to an immune antigen (CTLA-4) on cancer cells that transmits a signal inhibiting other from destroying the tumor. Ipilimumab blocks CTLA-4, thereby inducing an active immune response.
It's beautiful, I love that sort of precision. There has been other research highlighting that tumour cells do release humoral factors which inhibit the immune response. The research is active in this area and I think it will bring great benefit. They may have got lucky with melanoma because cancer cells demonstrate an uncanny adaptive capacity so the inhibition of one pathway may not be sufficient. It is immportant to remember that these results are statistical, you simply don't find evidence of 100% efficacy for an agent against tumours. There is now a clear reason for that: recent studies highlight how tumours are not heterogeneous in their make up, varying genetic signatures and cell types are found throughout large tumours. That very much highlights the value of an early diagnosis, recovery from small tumours is much better because the enemy hasn't had time to evolve. 
Mono-clonal antibodies are a very important component of our arsenal against cancers but there is no magic about it. The technology has arisen through decades of difficult thinking, experimenting, and application. There will come a day when mAbs will standard treatments for a range of pathologies, I won't be around to see that but I know this technology has a long way to go in realising its potential. 

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