An investigation into components of the surface layer of the skin that help protect against the spread of skin cancer

Linked Article:   Caley et al. Br J Dermatol 2021; 184 :923–934. Cutaneous squamous cell carcinoma (cSCC) is the second most common type of skin cancer in Western countries. Arising in the surface layer (epidermis) it has the ability to penetrate into the deeper layer (dermis), to spread to others parts of the body, and occasionally kill the patient. Natural protections against such spread include the body’s immune reaction and also the basement membrane, a structure which separates the epidermis from the dermis. Laminin subunit alpha‐3 is a specific component of the basement membrane. This collaborative study by investigators in several European countries and the USA investigated the role of laminin subunit alpha‐3 in influencing cSCC invasion and the immune reaction to the tumour. A variety of laboratory techniques was used including examining slides of previous cSCC cases, growing cancer cells in culture, and grafting genetically modified skin onto laboratory mice. They found that more aggressive tumours were associated with reduced expression of laminin subunit alpha‐3. Also, loss of laminin subunit alpha‐3 promoted increased production of an inflammatory cell called a tumour‐associated macrophage, which facilitate tumour invasion and spread. These findings suggest that assessing laminin subunit alpha‐3 expression in cSCC specimens might have useful prognostic value. They also suggest potential targets for therapy against elements of the immune response to these tumours.