Recent data support the high level of versatility of the technique, with the identification of a series of housekeeping proteins, such as Rab5b, CD81, and CD63, and tumor-specific markers, such as PSA, but also surrogate tumor markers, such as Cav-1 and carbonic anhydrase [24,43,44,46,47,53]. The gene discussed is CD63; the disease is neoplasm.