Translational Therapeutics

British Journal of Cancer (2007) 96, 445–449. doi:10.1038/sj.bjc.6603596 www.bjcancer.com
Published online 23 January 2007

Ki67 expression levels are a better marker of reduced melanoma growth following MEK inhibitor treatment than phospho-ERK levels

K S M Smalley1, R Contractor1, N K Haass1, J T Lee1, K L Nathanson2,4, C A Medina2, K T Flaherty3,4 and M Herlyn1

  1. 1The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania, 19104, USA
  2. 2Division of Medical Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
  3. 3Hematology-Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
  4. 4Abramson Cancer Center of the University of Pennsylvania, Philadelphia, PA 19104, USA

Correspondence: Dr KSM Smalley, E-mail: ksmalley@wistar.org

Revised 13 December 2006; Accepted 19 December 2006; Published online 23 January 2007.

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Abstract

The loss of tumour phospho-extracellular responsive kinase (pERK) positivity is the major treatment biomarker for mitogen-activated protein kinase/extracellular responsive kinase (MEK) inhibitors. Here, we demonstrate that there is a poor correlation between pERK inhibition and the anti-proliferative effects of MEK inhibitors in melanoma cells. We suggest that Ki67 is a better biomarker for future clinical studies.

Keywords:

melanoma, Ki67, biomarker, BRAF, MAP kinase, Akt