596 Mass spectrometry imaging: From skin cancer to melanoma

Abstract

Non-melanoma is a skin cancer that slowly develops in the upper layers of the skin. The term non-melanoma distinguishes more common types of skin cancer from less common skin cancer known as malignant melanoma. While classic histologic criteria have been described extensively over the past four or five decades, interpretation of these criteria in clinical practice still remains difficult. Today, the differences in appearance of a normal or a malignant lesion can be difficult to tell when just using light microscopy. Moreover, due to its differential growth, melanoma can spread quickly to other parts of the body through the lymph or circulatory systems. Those difficult calls that pathologists have may be overpassed by an adding value with mass spectrometry imaging (MSI) technology. Newer histological and molecular criteria/factors could be highlighted by MSI, which is able to simultaneously record the distribution of hundreds of biomolecules directly from tissue, without labeling and without prior knowledge. MSI is suited to biomedical research because the MSI-analyzed tissue section can be aligned with high definition histological images. The molecular signatures from specific histopathological entities may be extracted from the often-heterogeneous tissues encountered in biomedical research, especially in oncology. Our pre-clinical studies present examples that englobes pharmacokinetics, pharmacodynamics and toxicity analyses, all accomplished by MALDI MSI of skin.. Different compounds penetration profiles, metabolism, accumulation and tissue sub-structures targeting has been well highlighted. The results show a high co-localization histological specificity between the compound and its targeted area, where metabolites, lipids, peptides could be identified as treatment response biomarkers. These are key information for the evaluation of active compounds that will provide an understanding of diagnostic and prognostic factors in cutaneous melanoma. Finally, all these findings may give more information in available or new treatment modalities, as personalized medicine.