Proteomic analysis shows that the main constituent of subepidermal localised cutaneous amyloidosis is not galectin-7

Abstract

Lichen or macular localised cutaneous amyloidoses have long been described as keratinic amyloidoses and believed to be due to the deposition of cytokeratin peptides originating from epidermis in the dermal papillae. However, recently it was suggested that galectin-7 is the causative protein for this type of amyloidosis. This was based on the detection of galectin-7 in a biopsy from a patient diagnosed with Bowen’s disease and localised cutaneous amyloidosis. In this study we report mass spectrometry-based proteomic analysis of the protein composition of localised cutaneous amyloid deposits from seven patients using laser microdissection and show that basal keratins are the main constituents of the amyloid deposits. Galectin-7 was not present in the dermal amyloid deposits and was only present in the overlying Congo red negative epidermis.

Keywords:

• Amyloidosis
• keratin
• galectin-7
• cutaneous
• mass spectrometry
• laser microdissection

Disclosure statement

A Dogan has received personal consultancy fees from Roche, Corvus Pharmaceuticals, Physicians’ Education Resource, Seattle Genetics, Peerview Institute, Oncology Specialty Group, Pharmacyclics, Celgene, Novartis, Takeda, EUSA Pharma and research grants from National Cancer Institute and Roche. Other authors have no relevant affiliations or financial involvement with any organisation or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

This work was supported by the Farmer Family Foundation, the Susan and Peter Solomon Divisional Genomics Program, and the National Institutes of Health, National Cancer Institute Cancer Center Support Grant P30 CA008748.