PTGS2 and classic Hodgkin lymphoma: Ohsava et al., Hsu et al., and Hazar et al. observed the cox-2 expressions in classical Hodgkin lymphoma (CHL) and detected cytoplasmic cox-2 expression in 7(70%) of 10 CHL cases, 7(70%) of 10 CHL cases 15 (48%) of 31 CHL cases, respectively [7,27].