Geburtshilfe Frauenheilkd 2008; 68 - PO_Onko_04_31
DOI: 10.1055/s-0028-1089303

Which tyrosinekinase inhibitor for which patient? – VEGFR, target therapy

C Schem 1, M Kummerfeld 1, DO Bauerschlag 2, C Mundhenke 3, B Sipos 4, N Maass 3
  • 1Universitätsklinikum Schleswig-Holstein, Campus Kiel, Klinik Gynäkologie u. Geburtshilfe, Kiel
  • 2Klinik für Gynäkologie und Geburtshilfe, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel
  • 3Universitätsfrauenklinik Kiel, UK-SH, Campus Kiel, Kiel
  • 4Universitätsklinikum Schleswig-Holstein, Campus Kiel, Institut für Pathologie, Kiel, Kiel

Since the specific HER2 antibody trastuzumab is available, targeted therapy for breast cancer patients is becoming more and more the focus of new drug development. Additional tyrosine kinase inhibitors or antibodies are flooding the market for breast cancer treatment. Currently there are no indices available pointing out which patient will benefit best from these drugs.

In this study we analyzed 156 paraffin embedded breast cancer and 55 matching lymphnode tissue samples for VEGFR 1/2, PDGFR α/β, FLT3 and cKIT expression. Corresponding clinical data was taken into account. All samples were evaluated by experienced breast cancer pathologists.

Tyrosine kinase expression of VEGFR1/2 correlates with the nodal status (p<0,05) but does not correlate with the grading of the primary cancer site. VEGFR2 correlates with estrogenreceptor expression (p<0,05) The majority of breast cancer patients have a moderate or high expression of VEGFR1 whereas most patients have a low VEGFR2, PDGFRβ, FLT3 and cKIT expression. PDGFRα expression is in 42% moderate or high. The receptor expression of the lymphnode metastases correlates with the expression of the primary tumor (p<0,05). Correlations with clinical data and HER2 status will be presented.

Measured by IHC, most patients will benefit from VEGFR1 inhibition. But subgroups will also benefit from PDGFR inhibition. cKIT and FLT3 expression does not seem to have a clinical relevance for breast cancer patients. Clinical trials already showed positive effects of VEGFR antagonists in the treatment of palliative breast cancer patients. Ongoing trials will provide more defined answers. The future will tell if IHC pretreatment evaluation of target expression is valuable.