marker may be predictive of who will develop Tykerb rash
 

1: Ann Oncol. 2007 Sep 17; [Epub ahead of print]
Markers in the epidermal growth factor receptor pathway and skin toxicity during erlotinib treatment.

Tan AR, Steinberg SM, Parr AL, Nguyen D, Yang SX.
Medical Oncology Branch, Center for Cancer Research.
BACKGROUND: Skin toxicity is a common adverse effect of erlotinib and other anti-epidermal growth factor receptor (EGFR) agents. The aim of the study was to explore the relationship between markers in the EGFR pathway and skin rash. PATIENTS AND METHODS: Eighteen patients with metastatic breast cancer were treated with daily oral erlotinib at 150 mg. Skin biopsies were obtained at baseline and after 1 month of treatment in 15 patients. EGFR, phosphorylated EGFR (pEGFR), phosphorylated mitogen-activated protein kinase (pMAPK), and phosphorylated Akt (pAkt) or Ki67 were examined quantitatively by immunohistochemistry. RESULTS: 11 of 18 (61%, 95% confidence interval 35.7% to 82.7%) patients developed skin rash. pAkt at baseline was significantly higher in patients with no rash than those with a grade 1 or 2 rash (18.8 +/- 8.3 versus 2.4 +/- 1.2 versus 3.3 +/- 3.3; P = 0.0017 for trend). There was a trend towards a significant increase of pMAPK in skin posttreatment with increasing grade of rash (no rash versus grade 1 versus grade 2 rash: 4.5 +/- 2.3 versus 8.4 +/- 4.2 versus 19.4 +/- 4.6; P = 0.036). Other markers were not associated with rash. CONCLUSIONS: pAkt was significantly associated with not developing a rash and may have a predictive utility for skin toxicity in patients treated with erlotinib and possibly with other anti-EGFR agents.
PMID: 17878175 [PubMed - as supplied by publisher]