Skin Tumor Biomarkers by Mass Spectrometry Imaging

The purpose of the study is to investigate the ability of mass spectrometry imaging to locate aggregates of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) ex-vivo, and to distinguish areas containing these carcinomas from normal skin. It is suggested that non-melanoma skin cancer (NMSC) cells show a different profile of endogenous lipids than healthe skin tissue which can be used as identifying biomarkers. If that hypothesis is correct it will be possible in the future to develop real-time tissue diagnosis and treatment of NMSC using mass spectrometry guided surgery. Method between 60 and 100 patients with BCCs, SCCs, and actinic keratoses (AK) will be recruited. For patients referred for Mohs surgical procedure at the Department of Dermatology, Bispebjerg Hospital, to treat BCCs or SCCs, three skin sections (5-10 um thick) of the tissue that is already removed will be use in our study. One section will be HE stained so we know exactly where the regions of interest are. Two sections will be used for MS analysis (MSI spectrum and REIMS spectrum). When patients are referred for a procedure to have treated several actinic keratoses (grade 1, 2 or 3) at Department of Dermatology, Bispebjerg Hospital we will take an extra punch biopsy (2-4 mm) depending on the size of the lesion. The biopsy is embedded and sectioned. We will use 3 skin sections (5-10 um thick) we will again use one section for HE staining and two for MS analysis. Multivariate statistical analysis will be performed on all mass spectra using Matlab or similar program. Linear discriminant analysis will be used to identify spectral differences between pre-malignant, cancer and normal tissue. Classification performance will be recorded with a leave-one- patient- out cross- validation scheme.