RT Journal Article SR Electronic T1 CDKN1B/p27 expression in peripheral T cell lymphoma not otherwise specified JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 83 OP 87 DO 10.1136/jcp.2010.083832 VO 64 IS 1 A1 Gazzola, Anna A1 Sista, Maria Teresa A1 Agostinelli, Claudio A1 Righi, Simona A1 Sapienza, Maria Rosaria A1 Mannu, Claudia A1 Rossi, Maura A1 Bacci, Francesco A1 Sabattini, Elena A1 Went, Philip A1 Zinzani, Pier Luigi A1 Pileri, Stefano A A1 Piccaluga, Pier Paolo YR 2011 UL http://jcp.bmj.com/content/64/1/83.abstract AB Aims Peripheral T cell lymphoma not otherwise specified (PTCL/NOS) is the commonest PTCL subtype. Recently, proliferation pathways have been found to be commonly altered in PTCL/NOS. CDKN1B/p27, a critical regulator of cell cycle and proliferation, has been suggested to be involved in T cell lymphomagenesis. This study aimed to evaluate the possible occurrence of CDKN1B/p27 aberrations in PTCL/NOS.Methods CDKN1B/p27 expression at RNA and protein level by DNA and tissue microarrays, in 28 and 98 cases, respectively, was studied. Additionally, direct sequencing of CDKN1B in 81 PTCL/NOS was performed.Results CDKN1B mRNA was similarly expressed in PTCL/NOS and normal T lymphocytes. In addition, structural abnormalities were not found; these included mutations and deletions in any exons, exon–intron junctions or regulatory regions. Furthermore, physiological expression of p27 in neoplastic cells was demonstrated by immunohistochemistry; this was mutually exclusive with Ki-67, as expected when the system is intact. Consistently, the expression of other molecules that are functionally related to CDKN1B/p27 in controlling cell cycle (including CCNE1) did not appear to be affected at either the mRNA or protein level. Finally, it was found that p27 expression was not significantly related with overall survival.Conclusion CDKN1B/p27 aberrations seem to be uncommon in PTCL/NOS pathogenesis.