Issues

Cutaneous squamous cell carcinomas (cSCC) are among the most common human malignancies worldwide, with rapidly increasing incidence and associated morbidity and mortality. Human cSCC carry an extraordinarily high mutation burden, which is caused primarily by exposure to solar UV radiation. Whole exome sequencing of tumors that form in SKH-1 hairless mice following chronic intermittent exposure to solar-simulated UV radiation revealed a high similarity with human cSCC in terms of both frequency and type of mutations. The most frequent mutations are in Trp53 and genes encoding multiple Notch family members. Macroscopically, many animals display a “field change,” also known as “field cancerization,” which is a typical representation of the clinical situation. Additionally, the histopathological spectrum of the murine cSCC that develops in this model resembles very closely the spectrum of human cSCC. The cover micrograph shows an early invasive SCC that displays irregular budding with a tongue of squamous cells extending into the stroma, as well as single cell invasion. See article by Knatko, Praslicka, and colleagues (beginning on page 67) for more information.