title: Thymidine phosphorylase expression in B-cell lymphomas and its significance: a new prognostic marker?
abstract: OBJECTIVE
  To explore thymidine phosphorylase (TP) expression in B-cell lymphomas (BCLs). TP is expressed by tumor and stromal cells in a variety of cancers.
  
  
  METHODS
  Paraffin-embedded tissues from follicular lymphomas, diffuse large BCLs (DLBCLs), and benign lymph nodes were studied using immunohistochemical staining with antibodies for TP and CD68. Prognostic markers were used to stain DLBCLs. We correlated TP expression in DLBCL indirectly with prognostic immunomarkers and directly with survival data.
  
  
  RESULTS
  TP expression in BCLs was noted in a subset of malignant B cells. TP expression in higher-grade lymphoma was identified in 66% of cases and 11% of lower-grade lymphomas. Macrophages/stromal cells demonstrated an intense cytoplasmic and/or nuclear staining pattern in both lymphoma and benign lymph nodes, confirmed by CD68 coexpression. Increased macrophage/ stromal cells in higher-grade lymphomas are associated with enhanced TP expression in neoplastic B cells (observation only). Sixty-eight percent of TP-positive DLBCLs were of nongerminal center origin, indicating poorer prognosis.
  
  
  CONCLUSIONS
  TP is more likely expressed by malignant B cells in higher-grade lymphomas, and expression of TP possibly results from changes intrinsic to the tumor cells or interactions between microenvironment and tumor. TP positivity in DLBCL correlates with nongerminal center origin and worse outcome.
authors.forename: Xingcao
authors.initials: X
authors.lastname: Nie
authors.forename: Peter M
authors.initials: PM
authors.lastname: Clifford
authors.forename: Rekha
authors.initials: R
authors.lastname: Bhat
authors.forename: Rebecca
authors.initials: R
authors.lastname: Heintzelman
authors.forename: Mini
authors.initials: M
authors.lastname: Abraham
authors.forename: J Steve
authors.initials: JS
authors.lastname: Hou
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D016393:Lymphoma, B-Cell / Q000201:enzymology* / Q000401:mortality / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D013939:Thymidine Phosphorylase / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D014408:Biomarkers, Tumor; D013939:Thymidine Phosphorylase