Biomedical subjects

Sherrie L Perkins

Publications and source records attributed to Sherrie L Perkins.

At least 37 records · Page 2Linked to original sources

PubMed2004

Immunohistochemical expression patterns of germinal center and activation B-cell markers correlate with prognosis in diffuse large B-cell lymphoma.

Recent studies with cDNA microarrays showed that diffuse large B-cell lymphoma (DLBCL) cases with gene expression profiles similar to germinal center (GC) B cells had much better prognosis than DLBCL cases with gene expression profiles resembling activated B cells. The goal of the current study is to evaluate if using a panel of GC B-cell (CD10 and Bcl-6) and activation (MUM1/IRF4 and CD138) markers by immunohistochemistry defines prognosis in patients with de novo DLBCL. Immunohistochemical stains for the above markers were performed on paraffin-embedded tissues from 42 de novo DLBCL patients. Median follow-up in all patients was 41 months (range, 1-103 months) and in surviving patients was 65 months (range, 14-103 months). These cases could be classified into three expression patterns: GC B-cell pattern (pattern A) expressing CD10 and/or Bcl-6 but not activation markers; activated GC B-cell pattern (pattern B) expressing at least one of GC B-cell markers and one of activation markers; and activated non-GC B-cell pattern (pattern C) expressing MUM1/IRF4 and/or CD138 but not GC B-cell markers. Patients with pattern A had much better overall survival than those with the other two patterns (Kaplan-Meier survival analysis, P < 0.008, log rank test). Using multivariate Cox proportional hazards regression analysis, the international prognostic index scores and the expression pattern of these markers were independent prognostic indicators. Our results suggest that expression patterns of this panel of GC B-cell and activation markers by immunohistochemistry correlate with the prognosis of patients with DLBCL. Immunohistochemical analysis on paraffin-embedded tissues is more readily available than gene expression profiling by cDNA microarray and may provide similar prognostic information.

Adult↗

PubMed2004

Chromosome abnormalities may correlate with prognosis in Burkitt/Burkitt-like lymphomas of children and adolescents: a report from Children's Cancer Group Study CCG-E08.

Among pediatric non-Hodgkin lymphomas, the most frequent type is small noncleaved-cell lymphoma (including Burkitt and Burkitt-like). Specific chromosome abnormalities are associated with prognosis in childhood acute lymphoblastic leukemia (ALL); however, chromosome abnormalities have not been evaluated for prognostic value in pediatric Burkitt and Burkitt-like lymphomas. For Children's Cancer Group protocol CCG-E-08 Etiologic Study of Non-Hodgkin Lymphoma in Childhood, 19 patients were enrolled with cytogenetic analysis of Burkitt or Burkitt-like lymphoma and simultaneously enrolled on treatment protocols CCG-503 or CCG-552. Pathology material and karyotypes at initial diagnosis underwent central review. Demographics included an age range of 2 to 14 years (median 8 years) and a male:female ratio of 14:5. All patients had advanced disease (stages III and IV, or ALL). Disease relapsed in five patients (event-free survival 74%, median follow-up 10.4 years). Chromosome abnormalities were identified in 18 patients (95%) including t(8;14)(q24.1;q32) in 12 (63%); t(8;22)(q24.1;q11.2) in 1 (5%); partial duplication of 1q in 7 (37%); and 13q32 abnormalities in 2 (11%). In patients who had relapses, in addition to the t(8;14)(q24. ;q32), two had abnormalities of 13q32 and two had partial duplication of 1q. CMYC translocations were absent in Burkitt-like lymphomas from all three patients. Burkitt and Burkitt-like lymphomas in children have a high frequency of chromosome abnormalities. Burkitt lymphoma abnormalities often involve CMYC translocations, usually a t(8;14)(q24.1;q32). Additional chromosome abnormalities that involved 13q32 and partial duplication of 1q were associated with poor prognosis. Burkitt-like lymphomas were not associated with CMYC translocations. Further studies are warranted in larger cohorts of children and adolescents with Burkitt and Burkitt-like lymphomas.

Adolescent↗

PubMed2004

Pediatric red cell disorders and pure red cell aplasia.

Anemia in children may arise from a wide variety of pathogenetic mechanisms that include congenital and acquired disorders. Often the diagnostic considerations include disorders that are not seen commonly in adults and lifelong disorders that arise in children and persist throughout life. Consideration of diverse causes of anemia such as red cell membrane disorders, red cell enzymopathies, congenital dyserythropoietic anemias, congenital sideroblastic anemias, and hereditary pure red cell aplasia (Diamond-Blackfan anemia), as well as infectious causes such as parvovirus B19 infection, often is required when diagnosing anemia in an infant or young child. Knowledge of these entities that are important causes of anemia in the pediatric population, including clinical manifestations and laboratory workup, will aid in recognition of the specific disease entities and effective workup of pediatric red cell disorders.

Anemia↗

PubMed2004

Comparative immunohistochemical analysis of pediatric Burkitt lymphoma and diffuse large B-cell lymphoma.

Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) account for nearly all pediatric nonlymphoblastic B-cell lymphomas. Because clinical behavior, prognosis, and response to therapy might differ, diagnostic accuracy is important. Morphologic examination often is sufficient, but occasionally, diagnostic ancillary studies are required. In adults, immunophenotyping is useful; however, pediatric data are limited. We characterized the immunohistochemical expression of 6 proteins (c-myc, CD10, bcl-6, bcl-2, CD138, and MIB-1) in pediatric BL (33 cases) and DLBCL (20 cases) with classic morphologic features. Significant differences in c-myc (BL, 30/33 [91%] vs DLBCL, 5/20 [25%]; P < .0001), bcl-2 (BL, 1/25 [4%] vs DLBCL, 7/19 [37%]; P < .02), and mean MIB-1 (BL, 99% vs DLBCL, 56%; P < .0001) expression were observed. There were no significant differences for CD10 (100% expression in BL and DLBCL), bcl-6 (BL, 23/33 [70%] vs DLBCL, 15/20 [75%]), or CD138 (no expression). Thus, pediatric BL and DLBCL have distinctive immunohistochemical profiles, and staining for c-myc, MIB-1, and bcl-2 might be useful in morphologically difficult cases.

Adolescent↗

PubMed2004

Advances in the diagnostic approach to childhood lymphoblastic malignant neoplasms.

Acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL) not only are the most common cancer in children, but also among the most curable. Contemporary therapy has achieved highly successful survival rates by risk stratification into low- and high-risk treatment groups. This has permitted tailoring therapy intensity to produce higher remission rates, even in unfavorable prognostic groups. Accurate diagnosis, subclassification, and identification of relevant prognostic factors for lymphoblastic malignant neoplasms, using a multiparametric approach including immunophenotyping, cytogenetic and molecular analysis, and more traditional pathologic criteria, provides information that allows each patient to receive appropriate treatment.

Child↗

PubMed2004

Assessing immunoglobulin heavy chain rearrangements in pediatric CD20-positive and CD20-negative classic Hodgkin's disease.

Approximately 15% of all cases of childhood classical Hodgkin's disease (HD) express CD20, a B-cell marker associated with immunoglobulin heavy chain rearrangements. Immunoglobulin heavy chain rearrangements in Reed-Sternberg cells could be used to assess minimal residual disease (MRD), as was shown with immunoglobulin heavy chain patient-specific primers (PSPs) in non-Hodgkin's lymphoma. The aim of this study was to analyze pediatric HD for future design of immunoglobulin heavy chain PSP for MRD detection. DNA was extracted from paraffin-embedded tissue from unstained slides of 8 pediatric CD20+ nodular sclerosis HD cases and 10 CD20-nodular sclerosis HD cases. Immunoglobulin heavy chain polymerase chain reaction and sequencing were performed on 16 of 18 cases, which had adequate DNA for further analysis. Sequence analysis from 3 cases (19% of HD cases) demonstrated unique V(D)J regions, which could potentially be used to design PSP. Unique PSPs could be used to assess MRD in advanced-stage HD specimens. Future studies should focus on improved detection and analysis of more cases to identify appropriate specimens in assessing clinical implications of MRD detection.

Adolescent↗

PubMed2003

Involvement of multiple signaling pathways in follicular lymphoma transformation: p38-mitogen-activated protein kinase as a target for therapy.

Follicular lymphoma (FL) is the most common form of low-grade non-Hodgkin's lymphoma. Transformation to diffuse large B cell lymphoma (DLBCL) is an important cause of mortality. Using cDNA microarray analysis we identified 113 transformation-associated genes whose expression differed consistently between serial clonally related samples of FL and DLBCL occurring within the same individual. Quantitative RT-PCR validated the microarray results and assigned blinded independent group of 20 FLs, 20 DLBCLs, and five transformed lymphoma-derived cell lines with 100%, 70%, and 100% accuracy, respectively. Notably, growth factor cytokine receptors and p38beta-mitogen-activated protein kinase (MAPK) were differentially expressed in the DLBCLs. Immunohistochemistry of another blinded set of samples demonstrated expression of phosphorylated p38MAPK in 6/6 DLBCLs and 1/5 FLs, but not in benign germinal centers. SB203580 an inhibitor of p38MAPK specifically induced caspase-3-mediated apoptosis in t(14;18)+/p38MAPK+-transformed FL-derived cell lines. Lymphoma growth was also inhibited in SB203580-treated NOD-SCID mice. Our results implicate p38MAPK dysregulation in FL transformation and suggest that molecular targeting of specific elements within this pathway should be explored for transformed FL therapy.

Apoptosis↗

PubMed2003

Childhood and adolescent large-cell lymphoma (LCL): a review of the Children's Cancer Group experience.

We reviewed the clinical characteristics, treatment, and outcome of 67 children with localized and 212 with disseminated large-cell lymphoma (LCL) treated during a 20-year period in 5 consecutive Children's Cancer Group (CCG) non-Hodgkin's lymphoma (NHL) trials. Clinical outcomes for patients treated on the four earlier studies with moderate-dose chemotherapy administered over 12-18 months were compared with patients treated most recently with short, intensive therapy. Median age at diagnosis was 12 years (range: 0-19 years). Male to female ratio was 1.8:1.0. Five-year event-free survival (EFS) was 92% +/- 3.3% and 50 +/- 3.5% for patients with localized LCL and disseminated LCL, respectively. After adjustment for lactate dehydrogenase (LDH), age at diagnosis, and BM involvement, short and intensive therapy as delivered on the most recent study, CCG-5911, was associated with an improved outcome (P< 0.05) compared to the four previous studies. Elevated LDH (> or = 500 IU/L) at diagnosis and young age (<5 years) were both significant independent predictors of poorer long-term EFS (P< 0.05). Long-term survival after relapse or other treatment failure was only 31% +/- 4.7%. In summary, more recent shorter and intense therapy appears to be associated with superior event-free survival for children and adolescents with disseminated LCL. Large numbers of patients treated with shorter and intense therapy are required to confirm these preliminary observations.

Adolescent↗

PubMed2003

Burkitt's and Burkitt-like lymphoma in children and adolescents: a review of the Children's Cancer Group experience.

Historically, the survival of children and adolescents with Burkitt's and Burkitt-like lymphoma had been poor. Recently, short and intensive chemotherapy appears to have improved disease outcome. We therefore reviewed the results of four successive Children's Cancer Group trials conducted on 470 children with disseminated Burkitt's and Burkitt-like lymphoma. Of the patients studied, the median age was 8 years (0-21 years), the male:female ratio was 4:1, 58% had lactate dehydrogenase (LDH) > or = 500 IU/l, 23% had M2 or M3 bone marrow (BM), and 12% demonstrated central nervous system involvement. In a multivariate analysis, the 4-year event-free survival (EFS) in patients > or = 15-years-old compared with < 15-year-old was 34 +/- 7 versus 59 +/- 2% (P < 0.05), the 4-year EFS of M2/M3 compared with M1 BM was 38 +/- 5 versus 63 +/- 3% (P < 0.001), and the 4-year EFS with LDH > or = 500 IU/l compared with LDH < 500 IU/l was 49 +/- 3 versus 71 +/- 4% (P < 0.001). Furthermore, patients treated on the most recent protocol, which was short and more intensive, had a significantly improved survival compared with those on previous trials (4-year EFS 80 +/- 6 versus 54 +/- 2%, P < 0.001). In summary, the outcome for childhood Burkitt's and Burkitt-like lymphoma has recently improved with the use of short and intensive B-cell non-Hodgkin's lymphoma-directed therapy.

Adolescent↗

PubMed2003

BCL-2 is consistently expressed in hyperplastic marginal zones of the spleen, abdominal lymph nodes, and ileal lymphoid tissue.

BCL-2 is an antiapoptotic protein overexpressed in follicular lymphomas, principally as a result of the t(14;18)(q32;q21), and useful in distinguishing follicular lymphoma (usually BCL-2 positive) from follicular hyperplasia (BCL-2 negative). BCL-2 is also overexpressed in other lymphoma types without the t(14;18), including marginal zone B-cell lymphoma, because of other, poorly understood mechanisms. It has been suggested that BCL-2 immunoreactivity can distinguish between malignant (BCL-2 positive) and reactive (BCL-2 negative) marginal zone B cells. In this study, we evaluated 26 spleen, 10 abdominal lymph node, and 3 ileum specimens with marginal zone B-cell hyperplasia for BCL-2 expression immunohistochemically. We also analyzed these cases using polymerase chain reaction methods to evaluate for the presence of clonal rearrangements of the immunoglobulin heavy chain gene (IgH) using consensus V FRIII and J region primers, and the t(14;18) involving both the major breakpoint and the minor cluster regions of the bcl-2 gene. All (100%) cases of splenic, abdominal lymph node, and ileal marginal zone hyperplasia displayed strong BCL-2 reactivity in the marginal zone B cells. In all cases analyzed, IgH polymerase chain reaction demonstrated a polyclonal pattern, and bcl-2/JH DNA fusion sequences were not detected. Our results indicate that BCL-2 is consistently expressed by reactive marginal zone B cells of the spleen, abdominal lymph nodes, and ileal lymphoid tissue and should not be used as a criterion for discriminating between benign and malignant marginal zone B-cell proliferations involving these sites.

Abdomen↗

PubMed2003

Malignant peripheral nerve sheath tumor: a comparison of grade, immunophenotype, and cell cycle/growth activation marker expression in sporadic and neurofibromatosis 1-related lesions.

This study investigates differences in expression of the cell cycle/growth activation markers p53, p16, and p27, and their relationship with nerve sheath cell and proliferation markers among plexiform neurofibromas (PNF), NF1-related and non-NF1 MPNSTs of different histologic grades and between benign-appearing and malignant areas in the MPNSTs associated with PNFs. Formalin-fixed, paraffin-embedded archival tissue from PNFs and MPNSTs were immunostained using the avidin-biotin-complex method with antibodies to S-100 protein (S-100), Leu7 (CD57), CD34, p16, p27, p53, Mib-1, and topoisomerase II-alpha (TopoIIalpha), with appropriate controls. All PNFs and most low-grade MPNSTs displayed diffuse or focal reactivity for S-100, Leu7, CD34, p16, and p27 and negative reactivity for p53, Mib-1, and TopoIIalpha. Most high-grade MPNSTs displayed decreased or negative reactivity to S-100, Leu7, CD34, p16, and p27 but increased reactivity to p53 (59%), Mib-1 (72%), and TopoIIalpha (72%). In addition, combined nuclear and cytoplasmic (nucleocytoplasmic) p27 staining, which was not seen in the PNF or low-grade MPNST, was observed in 33% of high-grade MPNSTs. These findings suggest that p53, p16, and p27 may be involved in tumor progression in the PNF-MPNST sequence. However, alterations in p53, p16, and p27 do not distinguish between low-grade MPNST and PNF, including PNF adjacent to high-grade MPNST. Although p53, p16, and p27 are unlikely to be reliable markers for early detection of tumor progression in MPNST, p53 reactivity was more frequent in NF1-associated high-grade MPNST and appeared to be a marker for high tumor grade. Combining immunohistochemical stains with histologic grading with careful examination of mitotic activity may provide insight into the progression of peripheral nerve sheath tumors.

Adolescent↗

PubMed2003

Assessment of minimal residual disease in childhood non-hodgkin lymphoma by polymerase chain reaction using patient-specific primers.

A feasibility study was undertaken to identify patient-specific primers (PSPs) from childhood non-Hodgkin lymphoma (NHL) specimens to detect minimal residual disease (MRD). Eleven tumor specimens were amplified using immunoglobulin heavy chain and T-cell receptor primers to identify PSPs, which were then used to evaluate staging/follow-up specimens. Disease was detected in 19 of 21 staging and 16 of 17 follow-up specimens. Among seven patients in remission by 1 month, PSPs identified MRD in follow-up specimens. This study demonstrated the feasibility of PSPs to identify disease in staging and follow-up specimens, which could be used to develop strategies for MRD analysis in a larger setting.

Adolescent↗

PubMed2003

Analysis of the PI-3-Kinase-PTEN-AKT pathway in human lymphoma and leukemia using a cell line microarray.

Tissue microarray technology facilitates rapid assessment of expression of molecular markers by enabling the simultaneous analysis of hundreds of tissue specimens. We have applied this technology to establish a microarray composed of cell pellets derived from 40 human lymphoma/leukemia-derived cell lines harboring a variety of molecular abnormalities. The application of cell line microarrays to the assessment of biologic marker evaluation was validated by studying the immunohistochemical expression of PTEN and phosphorylated AKT, two mediators of the phosphatidylinositol (PI)-3-kinase pathway. In addition to the high throughout analysis of protein expression in lymphoma/leukemia cells, this methodology also enables the evaluation of subcellular localization of protein expression. Cytoplasmic PTEN expression was observed in the majority of cell lines (87%), whereas a minor subset demonstrated nuclear expression. Phosphorylated AKT was also expressed predominantly within the cytoplasm in 65% of cell lines, whereas nuclear expression was seen in a minority. An inverse relationship between PTEN and phosphorylated AKT was observed in 63% of cell lines. No cell lines showed absence of PTEN expression, whereas 50% of cell lines showed low PTEN expression. Our data support the integrity of the PI-3-kinase-PTEN-AKT pathway in a majority of cell lines derived from hematologic malignancies and clearly demonstrates the utility of microarray technology in the in situ assessment of expression of molecular markers in tumor-derived cell lines.

Biomarkers, Tumor↗

PubMed2003

Analysis of CD10+ hairy cell leukemia.

Hairy cell leukemia (HCL) has been reported to sometimes express CD10. However, the reported frequencies have been quite variable and the significance of CD10 expression has not been addressed. Cases of HCL submitted to our flow cytometry service during a 2-year period were evaluated for CD10 expression. Information regarding demographics, clinical manifestations, tissue morphologic features, and response to treatment was reviewed. Of the 97 HCL cases identified, 10 expressed CD10. The level of CD10 staining was typically well above control levels and also could be detected easily by immunohistochemical analysis. All cases analyzed were negative for bcl-6. Our study suggests that approximately 10% of otherwise typical cases of HCL show aberrant CD10 expression. CD10+ HCL cases seem to be morphologically and clinically similar to CD10-HCL cases. Appreciating that HCL can express CD10 may be especially important when evaluating specimens with suboptimal morphologic features and/or limited immunophenotyping panels.

Adult↗

PubMed2003

Follicular hyperplasia, follicular lysis, and progressive transformation of germinal centers. A sequential spectrum of morphologic evolution in lymphoid hyperplasia.

We studied mantle B-cell and T-cell ingression in hyperplastic follicles (HFs), follicular lysis (FL), and progressive transformation of germinal centers (PTGC) in 19 paraffin-embedded, H&E-, bcl-2-, CD20-, and CD3-stained lymph nodes. We enumerated the T cells (CD3+) and mantle B cells (bcl-2+/CD3-) per 100 cells in 5 high-power fields of each entity (mean +/- SD). Compared with HF, FL had increased numbers of T cells migrating into germinal centers (39.8 +/- 10.0 vs 25.8 +/- 7.8; P < .0001). and a mild increase of mantle B cells (12.3 +/- 11.4 vs 2.1 +/- 1.6; P < .001). PTGC showed an increase of T-cell ingression compared with HF (36.5 +/- 12.1 vs 25.8 +/- 7.8; P < .0001) and more migration of mantle B cells into the follicle than FL (41.0 +/- 22.5 vs 12.3 +/- 11.4; P < .0001). T cells and mantle B cells ingress in FL and PTGC, although the mantle B-cell component predominates in the latter, suggesting that follicular hyperplasia, FL, and PTGC constitute an evolutionary spectrum in resolution of lymphoid hyperplasia with sequential ingression of T cells followed by mantle B cells. The maintenance of bcl-2 expression in mantle B cells in PTGC may cause differential diagnostic pitfalls in florid PTGC vs follicular lymphoma, particularly the so-called floral variant.

B-Lymphocytes↗

PubMed2003

Expression of p53, c-Myc, or Bcl-6 suggests a poor prognosis in primary central nervous system diffuse large B-cell lymphoma among immunocompetent individuals.

CONTEXT: Primary central nervous system (CNS) diffuse large B-cell lymphoma (DLBCL) in immunocompetent individuals, although rare, has been rising in incidence. Currently, no reliable prognostic markers are available for these individuals. OBJECTIVE: To study the implications of expression of a panel of oncogenic proteins (Bcl-2, Bcl-6, and c-Myc) and p53 for predicting clinical outcome, particularly overall survival, in immunocompetent individuals with primary CNS DLBCL. DESIGN: Fourteen primary CNS DLBCL cases were retrospectively studied by immunohistochemistry on formalin-fixed, paraffin-embedded sections for the expression of c-Myc, Bcl-2, Bcl-6, and p53. RESULTS: The overall frequencies of expression for p53, c-Myc, Bcl-2, and Bcl-6 in these cases were 29%, 50%, 71%, and 57%, respectively. Cases with expression of p53, c-Myc, or Bcl-6 had a poorer overall survival than those without (Kaplan-Meier survival analysis: 50% cumulative overall survival, 2 months vs 30-60 months, P =.02, log-rank test; 9-16 months vs 21-60 months, P =.03, log-rank test; and 9-16 months vs 21-60 months, P =.16, log-rank test, respectively). The expression of Bcl-2 or proliferation activity by MIB-1 showed no correlation with overall survival. Likewise, the clinical parameters, including age, location of tumors, multiplicity of tumor lesions, and lactase dehydrogenase levels revealed no impact on overall survival. CONCLUSION: Our results suggest that patients with expression of p53, c-Myc, or Bcl-6 have a poorer overall survival than those without. Since traditional prognostic markers in non-CNS DLBCL, such as staging and International Prognostic Index scores, are not applicable to primary CNS DLBCL, evaluation of p53, c-Myc, and Bcl-6 by immunohistochemistry may be warranted as part of prognostic evaluation in immunocompetent patients with primary CNS DLBCL. Further studies are indicated to confirm our observations.

Adult↗

PubMed2003

B-Cell non-Hodgkin's lymphoma in children and adolescents: surface antigen expression and clinical implications for future targeted bioimmune therapy: a children's cancer group report.

Paraffin-embedded diagnostic biopsy materials from a large cohort of pediatric and adolescent patients with mature B-cell non-Hodgkin's lymphoma (NHL) treated on the Children's Cancer Group arm of an international cooperative trial were studied to determine their phenotypic features and the feasibility of using targeted bioimmune therapies. There were 345 patients eligible for analysis: 208 with Burkitt's lymphoma (BL), 43 with high-grade B-cell lymphoma, Burkitt-like (HGBL), and 94 with diffuse large B-cell lymphoma (DLBCL). Samples were immunophenotyped centrally using a standard panel that included CD20, CD79a, CD3, and CD45RO. Additional staining with CD22 was performed on a subset of cases. Immunophenotypic studies showed positive staining with CD20 in 100% of cases of BL and HGBL and in 98% of cases with DLBCL. CD22 expression was present in all cases of BL and DLBCL and in 87% of cases HGBL. This study indicates that immune-based therapies such as rituximab and ibritumomab-tiuxetan (anti-CD20) and epratuzumab (anti-CD22) are feasible in pediatric cases of mature B-cell NHLs.

Adolescent↗

PubMed2002

Expression of Skp2, a p27(Kip1) ubiquitin ligase, in malignant lymphoma: correlation with p27(Kip1) and proliferation index.

Reduced levels of p27(Kip1) are frequent in human cancers and have been associated with poor prognosis. Skp2, a component of the Skp1-Cul1-F-box protein (SCF) ubiquitin ligase complex, has been implicated in p27(Kip1) degradation. Increased Skp2 levels are seen in some solid tumors and are associated with reduced p27(Kip1). We examined the expression of these proteins using single and double immunolabeling in a large series of lymphomas to determine if alterations in their relative levels are associated with changes in cell proliferation and lymphoma subgroups. We studied the expression of Skp2 in low-grade and aggressive B-cell lymphomas (n = 86) and compared them with p27(Kip1) and the proliferation index (PI). Fifteen hematopoietic cell lines and peripheral blood lymphocytes were studied by Western blot analysis. In reactive tonsils, Skp2 expression was limited to proliferating germinal center and interfollicular cells. Skp2 expression in small lymphocytic lymphomas (SLLs) and follicular lymphomas (FCLs) was low (mean percentage of positive tumor cells, less than 20%) and was inversely correlated (r = -0.67; P <.0001) with p27(Kip1) and positively correlated with the PI (r = 0.82; P <.005). By contrast, whereas most mantle cell lymphomas (MCLs) demonstrated low expression of p27(Kip1) and Skp2, a subset (n = 6) expressed high Skp2 (exceeding 20%) with a high PI (exceeding 50%). Skp2 expression was highest in diffuse large B-cell lymphomas (DLBCLs) (mean, 22%) and correlated with Ki-67 (r = 0.55; P <.005) but not with p27(Kip1). Cytoplasmic Skp2 was seen in a subset of aggressive lymphomas. Our data provide evidence for p27(Kip1) degradative function of Skp2 in low-grade lymphomas. The absence of this relationship in aggressive lymphomas suggests that other factors contribute to deregulation of p27(Kip1) expression in these tumors.

Cell Cycle Proteins↗