p21/WAF1 cyclin-kinase inhibitor expression in non-Hodgkin's lymphomas: a potential marker of p53 tumor-suppressor gene function.
p21WAF1 (wild-type p53-activated fragment 1) is involved in the control of mammalian cell cycle through the binding and inhibition of cyclin-dependent kinases (Cdk). Because the product of WAF1 gene is a potent downstream effector of the p53 tumor-suppressor gene function, its pattern of cellular expression might correlate with nuclear accumulation of p53-encoded protein and/or p53 gene mutations occurring in malignant lymphomas. To investigate this issue, we analyzed immunohistochemically the expression of p53 and p21WAF1 proteins in tissue involved by non-Hodgkin's lymphomas (NHLs;253 cases) of various histologic types. In a proportion of them (80 cases), we also investigated the possible presence of p53 gene mutations using single-strand conformation polymorphism analysis and direct DNA sequencing. The absence of both p21WAF1 and p53 proteins was observed in 147 of 217 cases (67.7%) among CD30-NHL and in only 8 of 36 (22.2%) CD30+cases, which were mostly anaplastic large-cell lymphomas. A consistent number (> 10%) of p21WAF1-expressing cells was shown in 48 of 253 (18.9%) NHL cases, with a higher incidence in CD30+cases (25/36 [69.4%]), which mostly (21/36) coexpressed p53. These latter cases were characterized by a germline configuration of the p53 gene. In 50 of 253 NHL samples (19.7%), 47 of which (21.6%) belong to the CD30-group, neoplastic cells were p53+/p21-. In all of these cases, the p53+cells accounted for more than 50% of neoplastic cells, up to 100%. Point mutations of p53 gene were solely observed in all investigated cases with this latter phenotype. Our findings strongly suggest that the combined immunohistochemical evaluation of p53 and p21WAF1 is a valuable means of assessing the functional status of the p53 tumor-suppressor gene product in NHL with potential application in the monitorage and prognostication of individual cases.
Istituto di Anatomia Patologica, Università di Verona, Italy.
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M
Chilosi
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C
Doglioni
A
A
Magalini
G
G
Inghirami
M
M
Krampera
G
G
Nadali
D
D
Rahal
S
S
Pedron
A
A
Benedetti
M
M
Scardoni
E
E
Macrì
M
M
Lestani
F
F
Menestrina
G
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Pizzolo
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Scarpa
D015415:Biomarkers; D002453:Cell Cycle / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D016213:Cyclins / Q000096:biosynthesis* / Q000235:genetics; D004252:DNA Mutational Analysis; D016158:Genes, p53; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D012074:Remission Induction; D016896:Treatment Outcome; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
D015415:Biomarkers; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D009363:Neoplasm Proteins; D016159:Tumor Suppressor Protein p53; D018844:Cyclin-Dependent Kinases