Detektion methylierter Tumormarker in Kopf-Hals-Tumoren und in der Tumorumgebung

Objective: The recurrence rate in head and neck cancers (HNSCC) is high. Alterations in methylation patterns promote the emergence and recurrence of cancer. One hypothesis is that some cancers relapse due to incomplete resection undetected by standard histopathology. Due to the field cancerization concept, HNSCCs are surrounded by genetic and epigenetic alterations in histologically normal-appearing tissue. The aim of the study is to analyze HNSCC samples upon already established DNA methylation tumor markers (HOXA9, ZNF671, ZIC1, PAX6, ZNF833) at the tumor margins and the surrounding tissue. Methods: 15 HNSCC samples were collected during surgery and were frozen immediately. Adjacent sections were used for immunohistochemical staining (Ki-67, AE1/AE3, ASMA). Sections in between were placed on PEN-membrane slides used for laser capture microdissection (LCM). For DNA methylation analyses, methylation-specific real-time PCR (msPCR) upon the previously mentioned tumor markers was performed.Results: The immunohistochemical staining and msPCR could be well established. As expected, microdissected tumor cells show valid results with high methylation score for the tumor markers, whereas non-tumor cells show valid, but negative results. Next step is to analyze tissues, with the required morphology for addressing the question of field cancerization effects.Conclusion: Performing msPCR using cells from LCM for detecting DNA methylation of the tumor markers resulted in high sensitivity and specificity. A clear differentiation between tumor and non-tumor cells could be shown. Results regarding the detection of aberrant methylation in histo-pathologically normal tissue at the resection margins supporting or contradicting the field-cancerization effects will be shown at the congress.

Frau Dr. Wiehle, Frau Dr. Schmitz und Herr Sust sind Angestellte der oncgnostics GmbH.