PCNA and primary effusion lymphoma: Similarly, amino acid and DNA sequence analyses of KSHV, which has been strongly implicated as the etiologic factor in the development of Kaposi's sarcoma and primary effusion lymphomas (PEL) (Chang et al., 1994; Cesarman et al., 1995), identified a “cyclin-box” showing similarity to human cyclin D2 (Chang et al., 1996; Li et al., 1997).