SPRR2A and cancer: In particular, Desmoplakin (DSP), Desmocollin-1 (DSC1), Desmoglein-1 (DSG1), and small proline-rich protein 2A (SPRR2A) were identified only in lung cancer EVs and resulted from “cell-cell adhesion” process that, as already described, plays a pivotal role in the development and progression of cancer [64].