Low expression of p27 protein combined with altered p53 and Rb/p16 expression status is associated with increased expression of cyclin A and cyclin B1 in diffuse large B-cell lymphomas

Proliferating Pilar Tumors: Can Immunohistochemistry Differentiate Benign and Malignant Forms?

BACKGROUND

Proliferating pilar tumor (PPT) is an adnexal tumor of purported differentiation toward the follicular outer root sheath. Immunohistochemistry has been suggested to differentiate between benign and malignant forms.

METHODS

Eleven benign (PPT) and 9 malignant PPT lesions were reviewed; Ki67, p27, and p53 were applied. The staining intensity (strong, moderate, weak, and negative), positive cell numbers, and marker indexes (%) were scored using image-analysis software (ViraSoft).

RESULTS

Overall, there was no significant correlation between Ki67 and p53 and histopathological features. However, malignant PPTs had significantly lower numbers of p27-positive cells (P = 0.030).

CONCLUSIONS

Our study includes the largest group of patients in whom image analysis of p53, Ki67, and p27 has been used to try to separate benign from malignant lesions. Although there were no significant differences regarding Ki67 and p53, malignant lesions have a statistically lower expression of p27. Further studies may be needed to determine the clinical usefulness of image analysis in this differential diagnosis.

Assessment of DNA Methylation in p15, p16 and E-Cadherin Genes as a Screening Tool for Early Carcinoma Cervix

Cancer cervix is diagnosed late in women due to anatomical inaccessibility of the area. Hence, a robust screening strategy will help detect carcinoma cervix early which will significantly decrease the mortality and morbidity due to this disease. We evaluated DNA methylation of three tumour suppressor genes p15, p16 and E-Cadherin on cervical smears to assess DNA methylation as a screening tool for detection of early cervical cancer in comparison to PAP smears. DNA was extracted from cervical smears of 20 cases and 30 controls. The DNA was bisulphite modified. Methylation specific PCR (MSP) was performed to assess the methylation status of the promoter region of each of the genes. MSP results were compared with PAP smears to assess the utility of DNA methylation of these genes in screening for cervical cancer. DNA methylation was detected in 55% subjects in p15 gene, 45% in p16 gene and 40% in E-Cadherin gene. This was statistically significant when compared to the controls. DNA methylation of E-Cadherin, and p15 genes as a panel has a sensitivity and specificity of 80% and 90% respectively, which is better than the sensitivity of PAP smear for detection of early cancer cervix. Increased DNA methylation is seen in p15, p16 and E-Cadherin genes in early cancer cervix. p15 and E-Cadherin in combination can be used as a screening tool for detection of early cancer cervix.

Genomic Analyses Identify Recurrent Alterations in Immune Evasion Genes in Diffuse Large B-Cell Lymphoma, Leg Type

Cutaneous diffuse large B-cell lymphomas (DLBCLs) are aggressive lymphomas with a poor prognosis. To elucidate their genetic bases, we analyzed exome sequencing of 37 cutaneous DLBCLs, including 31 DLBCLs, leg type (DLBCL-LT) and 6 cutaneous DLBCLs-not otherwise specified (DLBCL-NOS). As reported previously, 77% of DLBCL-LT harbor NF-κB-activating MYD88 mutations. In nearly all MYD88-wild-type DLBCL-LT, we found cancer-promoting mutations that either activate the NF-κB pathway through alternative genes (NFKBIE or REL) or activate other canonical cancer pathways (BRAF, MED12, PIK3R1, and STAT3). After NF-κB, the second most commonly mutated pathway putatively enables immune evasion via mutations predicted to downregulate antigen processing (B2M, CIITA, HLA) or T-cell co-stimulation (CD58). DLBCL-LT have little genetic overlap with the genetically heterogeneous DLBCL-NOS. Instead, they resemble primary central nervous system and testicular large B-cell lymphomas (primary central nervous system lymphomas and primary testicular lymphomas). Like primary central nervous system lymphomas/primary testicular lymphomas, 40% of DLBCL-LT (vs. 0% of DLBCLs-not otherwise specified) harbored PDL1/PDL2 translocations, which lead to overexpression of PD-L1 or PD-L2 in 50% of the cases. Collectively, these data broaden our understanding of cutaneous DLBCLs and suggest novel therapeutic approaches (e.g., BRAF or PI3K inhibitors). Additionally, they suggest novel treatment paradigms, wherein DLBCL-LT can be targeted with strategies (e.g., immune checkpoint blockers) currently being developed for genomically similar primary central nervous system lymphomas/primary testicular lymphomas.

Ocular adnexal marginal zone lymphoma of mucosa-associated lymphoid tissue

Ocular adnexal lymphomas are a group of heterogeneous neoplasms representing approximately 1-2% of non-Hodgkin lymphomas and 8% of extranodal lymphomas. The incidence of primary ocular adnexal lymphoid tumors has raised over the last decades, and this could be probably attributed to the more sophisticated diagnostic techniques. Due to the wide spectrum of clinical manifestations, ocular tissue biopsy is important in order to set a precise diagnosis based on histological, immunophenotypical and, in some cases, molecular findings. The most common subtype, which may account for up to 80% of primary ocular adnexal lymphomas, is extranodal marginal zone lymphoma (EMZL) of mucosa-associated lymphoid tissue. This lymphoma is usually asymptomatic in the early phase of the disease causing a delay in the final diagnosis and prompt therapy. The pathogenesis of a proportion of these tumors has been linked to chronic inflammatory stimulation from specific infectious factors (e.g., Chlamydia psittaci) or to autoimmunity. The further improvement in diagnostic methods and the further understanding of the pathogenesis of ocular adnexal EMZL may contribute to the establishment of a more successful multidisciplinary therapeutic planning.

Expression patterns of the activator protein-1 (AP-1) family members in lymphoid neoplasms

The activator protein-1 (AP-1) is a dimeric transcription factor composed of proteins belonging to the Jun (c-Jun, JunB and JunD), Fos (c-Fos, FosB, Fra1 and Fra2) and activating transcription factor protein families. AP-1 is involved in various cellular events including differentiation, proliferation, survival and apoptosis. Deregulated expression of AP-1 transcription factors is implicated in the pathogenesis of various lymphomas such as classical Hodgkin lymphomas, anaplastic large cell lymphomas, diffuse large B cell lymphomas and adult T cell leukemia/lymphoma. The main purpose of this review is the analysis of the expression patterns of AP-1 transcription factors in order to gain insight into the histophysiology of lymphoid tissues and the pathology of lymphoid malignancies.

Status of p53 and p27(KIP1) in Iranian Patients With Oral Squamous Cell Carcinoma

Background:

Alterations in p53 and p27^KIP1 have been documented as important events in the carcinogenesis of various cancers, but their prognostic role in oral squamous cell carcinoma (OSCC) remains controversial.

Objectives:

The present investigation aimed to evaluate the clinicopathologic and prognostic significance of p53 and p27^KIP1 expression in a group of Iranian patients with OSCC.

Patients and Methods:

In this analytical cross-sectional study, medical records of patients with primary OSCC, diagnosed from 1994 to 2004 were reviewed and 28 subjects were selected based on the inclusion/exclusion criteria. Immunohistochemical staining using monoclonal antibodies against p53 and p27^KIP1 was performed on representative archival paraffin blocks. Demographic data along with information on p53 and p27^KIP1 expression, recurrence, and tumor grade was statistically analyzed using the Fischer exact test. Prognostic factors for overall survival were determined by Cox regression analysis (P < 0.05).

Results:

p53 and p27^KIP1 expression were found in 28.57% (8 positive versus 20 negative) and 67.85% (19 positive versus 9 negative) of OSCC cases, respectively. There was no significant association between these two proteins (P = 0.371), and neither of them showed a significant relationship with the studied clinicopathologic variables (P > 0.05). In survival analysis, only histopathologic differentiation (17 low and moderate, 11 poor) demonstrated a significant correlation with overall survival (P = 0.048).

Conclusions:

Despite the fact that abnormalities in p53 and p27^KIP1 may be involved in the development of OSCC, their clinical significance in the studied population seems limited. Further investigation on the combined p53/p27^KIP1 expression may be helpful in predicting the biologic behavior of this tumor.

The expression levels of JunB, JunD and p-c-Jun are positively correlated with tumor cell proliferation in diffuse large B-cell lymphomas

We analyzed the expression of Jun family in relation to CD30 expression, cell proliferation and B-cell differentiation immunophenotypes [Germinal Center and non-Germinal Center] in diffuse large B-cell lymphomas (DLBCL). Expression and high expression of phosphorylated-c-Jun (p-c-Jun), JunB, JunD and CD30 (cut-off scores 20% and 50%, respectively) was found in 18/103, 49/103, 72/101 and 26/102 cases, respectively, and in 6/103, 27/103, 60/101 and 21/102 cases, respectively. The following significant positive correlations were observed: (a) JunB with cyclin A (p = 0.046), cyclin B1 (p = 0.033), cyclin E (p = 0.003), MUM-1 (p = 0.002) and CD30 (p < 0.001), (b) JunD with Ki67 (p = 0.002) and cyclin E (p = 0.014), (c) p-c-Jun with CD30 (p = 0.015), and (d) high p-c-Jun with cyclin A (p = 0.034). The positive correlation between expression of JunB, JunD and p-c-Jun and tumor cell proliferation in DLBCL, suggests that increased JunB, JunD and p-c-Jun expression may be involved in the pathogenesis of DLBCL by increasing tumor cell proliferation.

Prognostic impact of serum 25-hydroxivitamin D [25(OH)D] concentrations in patients with lymphoid malignancies

The incidence of lymphoid malignancies has been increasing rapidly. Despite growing evidence for a relationship between serum 25-hydroxivitamin D [25(OH)D] concentrations and solid tumor risk, far less is known about the relationship between 25(OH)D and the risk of hematologic malignancy. This study aimed to assess the prognostic relevance of serum 25(OH)D concentrations in patients with B chronic lymphocytic leukemia (B-CLL) and non Hodgkin's lymphoma (NHL). The study was carried out on 195 newly diagnosed patients (75 B-CLL and 120 NHL) as well as 30 normal healthy controls. For all patients and normal controls serum 25(OH)D concentrations were assayed by enzyme-linked immunosorbent assay. Serum 25(OH)D levels were significantly lower in B-CLL and NHL patients as compared with normal controls (P = 0.00 for both). Also, there are significant associations between serum 25(OH)D levels and positive CD 38, positive ZAP 70 as well as Binet stages (χ(2) = 16.071, 16.644, 21.134 respectively; P = 0.00 for all) in the B-CLL patient group. Moreover, there are significant associations between serum 25(OH)D status and international prognostic index (IPI), performance status (χ(2) = 6.994, 9.212, P = 0.02, 0.01 respectively), but not with clinical stages (χ(2) = 3.115, P = 0.539) in NHL. Multivariate analysis revealed that 25(OH)D insufficiency is an independent poor prognostic factor in both B-CLL and NHL patient groups. In conclusion, 25(OH)D insufficiency is an independent poor prognostic factor in patients with B-CLL and NHL. 25(OH)D might be a therapeutic target in lymphoid malignancies.

Euphol from Euphorbia tirucalli selectively inhibits human gastric cancer cell growth through the induction of ERK1/2-mediated apoptosis

Gastric cancer is one of the most common malignancies worldwide, and the main cause of cancer-related death in Asia. The present study assessed the anticancer effects of euphol, a triterpene alcohol with anti-inflammatory and antiviral activities on human gastric cancer cells. Euphol showed higher cytotoxicity activity against human gastric CS12 cancer cells than against noncancer CSN cells. In addition, it up-regulated the pro-apoptotic protein BAX and down-regulated the prosurvival protein Bcl-2, causing mitochondrial dysfunction, possibly by caspase-3 activation. The anti-proliferative effects of euphol were associated with the increased p27(kip1) levels and decreased cyclin B1 levels. Inhibition of ERK1/2 activation by PD98059 reversed euphol-induced pro-apoptotic protein expression and cell death. Taken together, these findings suggest that euphol selectively induced gastric cancer cells apoptosis by modulation of ERK signaling, and could thus be of value for cancer therapy.

Early life sun exposure, vitamin D-related gene variants, and risk of non-Hodgkin lymphoma

PURPOSE

It has been hypothesized that vitamin D mediates the inverse relationship between sun exposure and non-Hodgkin lymphoma (NHL) risk reported in several recent studies. We evaluated the association of self-reported sun exposure at ages <13, 13-21, 22-40, and 41+ years and 19 single nucleotide polymorphisms (SNPs) from 4 candidate genes relevant to vitamin D metabolism (RXR, VDR , CYP24A1, CYP27B1) with NHL risk.

METHODS

This analysis included 1,009 newly diagnosed NHL cases and 1,233 frequency-matched controls from an ongoing clinic-based study. Odds ratios (OR), 95 % confidence intervals (CI), and tests for trend were estimated using unconditional logistic regression.

RESULTS

There was a significant decrease in NHL risk with increased sun exposure at ages 13-21 years (OR(≥15 vs. ≤3 h/week) = 0.68; 95 % CI, 0.43-1.08; p(trend) = 0.0025), which attenuated for older ages at exposure. We observed significant main effect associations for 3 SNPs in VDR and 1 SNP in CYP24A1: rs886441 (OR(per-allele) = 0.82; 95 % CI, 0.70-0.96; p = 0.016), rs3819545 (OR(per-allele) = 1.24; 95 % CI, 1.10-1.40; p = 0.00043), and rs2239186 (OR(per-allele) = 1.22; 95 % CI, 1.05-1.41; p = 0.0095) for VDR and rs2762939 (OR(per-allele) = 0.85; 95 % CI, 0.75-0.98; p = 0.023) for CYP24A1. Moreover, the effect of sun exposure at age 13-21 years on overall NHL risk appears to be modified by germline variation in VDR (rs4516035; p(interaction) = 0.0066). Exploratory analysis indicated potential heterogeneity of these associations by NHL subtype.

CONCLUSION

These results suggest that germline genetic variation in VDR, and therefore the vitamin D pathway, may mediate an association between early life sun exposure and NHL risk.

High levels of topoisomerase IIalpha protein expression in diffuse large B-cell lymphoma are associated with high proliferation, germinal center immunophenotype, and response to treatment

Gene copy number and protein expression of topoisomerase IIalpha were correlated to benefit from anthracyclines in various tumors. A retrospective series of 69 patients with DLBCL managed with CHOP chemotherapy were studied for immunohistochemical TopoIIalpha expression and numerical gene abnormalities by fluorescent in situ hybridization (FISH). The results were analyzed in relation to the expression of cell cycle proteins (Ki67, p53, HDM2, p21, p14, pRb, p16, and cyclins A, B1, D1, D2, D3, and E) and BCL6/CD10/MUM1/CD138 B-cell differentiation immunophenotype and outcome. High levels of TopoIIalpha protein were found in 91% of DLBCL cases. No evidence of TopoIIalpha gene amplification or deletion was found. The TopoIIalpha expression showed significant positive correlations with the proliferation index Ki67 (p = 0.002), cell cycle proteins pRb and cyclin D2 (p = 0.018 and p = 0.028, respectively), and the germinal center proteins bcl6 and CD10 (p = 0.010 and p < 0.0001, respectively). TopoIIalpha expression was significantly higher in germinal center B-cell like (GCB) DLBCL than in non-germinal center B-cell like (non-GCB) DLBCL (p = 0.048). TopoIIalpha protein was significantly associated with response to chemotherapy (chi(2), p = 0.024), but not with relapse-free or overall survival (p = 0.5). On multivariate analysis, only stage of disease retained independent prognostic significance (HR 0.33 for early stage, p = 0.008). Although TopoIIa gene copy number abnormalities were not found in DLBCL, high levels of protein expression are associated with GCB-cell differentiation immunophenotype, high proliferation, and response to treatment.

Vitamin D and non-Hodgkin lymphoma risk in adults: a review

Animal and human studies support a protective effect of vitamin D sufficiency related to malignancy by uncovering paracrine and autocrine effects of extra-renal 25-hydroxyvitamin D (25(OH)D) activation including regulation of cell cycle proliferation, apoptosis induction, and increased cell differentiation signaling. Recent epidemiologic studies demonstrate a reduction in non-Hodgkin lymphoma (NHL) risk with increased sunlight exposure. As sunlight is a major vitamin D source, it has been suggested that vitamin D status may mediate this observed association. This review provides a comprehensive discussion of the current epidemiologic evidence with regard to the investigation of an association between vitamin D status and NHL risk.

Interrelationships among chromosome aneuploidy, promoter hypermethylation, and protein expression of the CDKN2A gene in individuals from northern Brazil with gastric adenocarcinoma

Numerical alterations of chromosome 9, the status of promoter methylation and protein expression of the CDKN2A gene (aliases include p16 and p16(INK4a)), the possible association with gain of chromosome X, and the interrelation of these findings with clinic and pathological characteristics were investigated in gastric adenocarcinomas. Fluorescence in situ hybridization analysis with centromeric DNA probes, immunohistochemical staining, and methylation-specific polymerase chain reaction assays were performed in 15 gastric adenocarcinomas samples from individuals from northern Brazil. Aneuploidies of chromosomes X and 9 were found in all samples, both intestinal and diffuse type. Monosomy of chromosome 9 and gain of a copy of chromosome X (in both sexes) were observed in 100% of cases. Hypermethylation frequency and protein expression of CDKN2A were also found in all cases analyzed. No association of genetic and epigenetic alterations with histological type, tumor aggressiveness, and invasion was found (P > 0.05), which may be attributable to small sample size. There was a high level of association between absence of p16 protein expression levels, CDKN2A gene promote hypermethylation, and chromosome 9 aneuploidy (100% of cases). Thus, in the present samples, the apparent mechanisms behind p16 silencing include loss of chromosome 9 and promoter region hypermethylation.

A tree-based decision rule for identifying profile groups of cases without predefined classes: application in diffuse large B-cell lymphomas

In this paper, we examined the utility of a forward growing classification tree as a supplement to cluster analysis for deriving a decision rule for the identification of profile groups when the cases do not belong to predefined classes. The technique was applied for the identification of low and high proliferation profile groups of diffuse large B-cell lymphomas according to the immunohistochemical expression levels of proliferation proteins. In a forward growing classification tree method, the size of the tree is controlled by the improvement (threshold value) in the apparent misclassification rate after each split. The classes used in the tree were defined using k-means clustering. The decision rule consisted of the splitting points of the split variables used. The methodology was applied to the histology data from 79 cases of diffuse large B-cell lymphomas. Ten classes of individual cases were derived from k-means clustering. Then, a classification tree with a threshold of 2% was used to derive the decision rule. Branches at the left side of the tree consisted of individuals with a low proliferation profile and branches at the right side of the tree consisted of cases with a high proliferation profile. The classification tree, as a supplement method, not only identified but also provided decision rules for identifying profile groups. Finally, it also allowed for exploration of the data structure.

p27Kip1 is Detected on Most Gastric MALT Lymphomas, but not Large Cell Lymphomas

We investigated the relationship of gastric mucosa-associated lymphoid tissue (MALT) lymphoma tumorigenesis to Helicobacter pylori infection, the t (11;18) translocation, and alterations in cell cycle regulators. We sought to assess the implications of altered expression of p27(Kip1), a cyclin-dependent kinase inhibitor, on high-grade transformation and responsiveness to eradication therapy. We used immunohistochemistry to examine p27(Kip1), p53, and Ki-67 expression in 23 MALT lymphomas, five diffuse large B-cell lymphomas (DLBCLs), and four DLBCLs with associated MALT lymphoma. All of the MALT lymphomas were positive for p27(Kip1) expression and negative for p53 with a low Ki-67 index, regardless of the sensitivity of these cells to eradication. All DLBCLs were negative for p27(Kip1) and positive for p53, exhibiting a high Ki-67 index. In DLBCLs with MALT lymphoma, p27(Kip1) expression was absent from both the MALT and large cells components. In all of these lymphomas, the MALT components were negative for p53 and displayed a low Ki-67 index, while the large cell components were positive for p53 with a high Ki-67 index. The expression patterns of the DLBCLs differed significantly from those of the MALT lymphomas. p27(Kip1) was not detected in either component of DLBCL with MALT lymphoma, suggesting that decreased expression of p27(Kip1) in the MALT component may be related to high-grade transformation. Thus, p27(Kip1) expression in morphological MALT lymphomas could be useful tool to predict high-grade transformation to DLBCL.

p16 expression in the female genital tract and its value in diagnosis

p16 is a cyclin-dependent kinase-4 inhibitor that is expressed in a limited range of normal tissues and tumors. In recent years, immunohistochemistry with p16 antibodies has been used as a diagnostic aid in various scenarios in gynecologic pathology. Diffuse (as opposed to focal) positivity with p16 in the cervix can be regarded as a surrogate marker of the presence of high-risk human papillomavirus (HPV). In cervical squamous lesions, p16 is positive in most high-grade cervical intraepithelial neoplasia (CIN) and in some cases of low-grade CIN, usually those associated with high-risk HPV. p16 may be useful to identify small focal high-grade CIN lesions, to distinguish some cases of CIN involving immature metaplastic squamous epithelium from immature metaplastic squamous epithelium not involved by CIN and to distinguish high-grade CIN from benign mimics. Most cervical carcinomas of squamous, glandular, and small cell type are p16-positive. In cervical glandular lesions, p16 is useful, as part of a panel, in the distinction between adenocarcinoma in situ (diffusely positive) and benign mimics, including tuboendometrial metaplasia and endometriosis, which are usually p16-negative or focally positive. p16 may be used, in combination with other markers, to distinguish between a cervical adenocarcinoma (diffuse positivity) and an endometrioid-type endometrial adenocarcinoma (negative or focally positive). Some uterine serous carcinomas are diffusely positive. In the vulva, p16 is positive in HPV-associated vulval intraepithelial neoplasia (VIN) but negative in VIN not associated with HPV. Similarly, HPV-associated invasive squamous carcinomas are p16-positive, whereas the more common non-HPV-associated neoplasms are largely negative or focally positive. In the uterus, p16 positivity is more common and widespread in leiomyosarcomas than leiomyomas, and this may be a useful aid to diagnosis, although problematic uterine smooth muscle neoplasms have not been extensively studied. Metastatic cervical adenocarcinomas in the ovary are usually diffusely p16-positive, and because these may closely mimic a primary ovarian endometrioid or mucinous adenocarcinoma, this may be a valuable diagnostic aid, although p16 expression in primary ovarian adenocarcinomas of these morphologic subtypes has not been widely investigated. Some ovarian serous carcinomas, similar to their uterine counterparts, are p16-positive.

Expression and prognostic implications of cell cycle regulatory molecules, p16, p21, p27, p14 and p53 in germinal centre and non-germinal centre B-like diffuse large B-cell lymphomas

AIMS

To evaluate the different expression patterns and the prognostic significance of cell cycle regulatory molecules in diffuse large B-cell lymphomas (DLBCLs) of germinal centre (GC) and non-GC phenotypes.

METHODS AND RESULTS

Tissue microarray slides composed of 126 extranodal and 88 nodal DLBCLs were immunostained for p16, p21, p27, p14 and p53. DLBCLs were classified into GC and non-GC phenotype according to the immunohistochemical expression of bcl-6, CD10, and MUM1. Aberrant expression of p53 was more frequent in the GC phenotype in nodal cases (P = 0.038), and the loss of p16, p21 and p14 expression was significantly more common in the non-GC phenotype (P = 0.004, P = 0.001, P < 0.001). Concurrent disruptions of the p16-Rb and p14-p53 pathways as represented by the immunoprofile of p16/p14/p53 (-/-/+) were associated with a poor prognosis in the GC phenotype [mean survival 31 months in the p16/p14/p53 (-/-/+) group versus 62 months in the other groups, P =0.0485].

CONCLUSIONS

The expression and prognostic implications of cell cycle regulatory molecules differ between GC and non-GC phenotypes in DLBCLs. The immunoprofile of p16/p14/p53 (-/-/+) within the GC phenotype of DLBCLs can be defined as a poor prognostic subgroup.

T cell-dependent antibody responses against aberrantly expressed cyclin B1 protein in patients with cancer and premalignant disease

PURPOSE

Cyclin B1-derived peptides were shown by us to be targets of tumor-specific CD8(+) T cells in patients with breast and head and neck cancer. We obtained further evidence of cyclin B1 immunogenicity and its potential to serve as a tumor-specific antigen by analyzing its ability to elicit T cell-dependent humoral immune responses in vivo in patients with different types of tumors.

EXPERIMENTAL DESIGN

Recombinant cyclin B1 protein from two different sources was purified and used as antigen in ELISA assays to test sera from patients with breast, pancreatic, colon, and lung cancer for the presence of anti-cyclin B1 antibody. We also analyzed patients with benign lung disease, premalignant disease, and a known history of heavy smoking.

RESULTS AND CONCLUSIONS

Cyclin B1 elicits helper T cell-dependent antibody responses in vivo. Tumors with higher level of cyclin B1 expression elicit higher anti-cyclin B1 antibody levels. Antibodies in patients with breast and colon cancer are primarily of the IgG isotype whereas patients with pancreatic and lung cancer have in addition anti-cyclin B1 IgA. Cyclin B1-specific IgG was also detected in long-term smokers and in patients with preneoplastic lung disease. Immune responses to aberrantly expressed cyclin B1 in tumors and premalignant lesions should be further explored as diagnostic and prognostic markers, in addition to their immunotherapeutic potential.

Aberrant expression of tumor suppressor genes and their association with chimeric oncogenes in pediatric acute lymphoblastic leukemia

Aberrant expression of tumor suppressor genes WT 1, RB 1, p53, homozygous deletion of p16 gene and their relationship with expression of oncogenes BCR-ABL, TEL-AML 1, MLL-AF 4, E2A-PBX 1, SIL-TAL 1 were determined in bone marrow samples of children with de novo B-lineage (n=170) and T-lineage (n=25) acute lymphoblastic leukemia (ALL). In contrast to expression of chimeric oncogenes alterations in p16, WT 1, RB 1 and p53 expression were T/B-lineage-unrestricted. Significant association between expression of MLL-AF 4 and WT 1, E2A-PBX 1 and p53; SIL-TAL 1 and homozygous deletion of p16 has been demonstrated.

Proliferation profile of classical Hodgkin's lymphomas. Increased expression of the protein cyclin D2 in Hodgkin's and Reed-Sternberg cells

There is accumulating evidence that Hodgkin's and Reed-Sternberg cells of classical Hodgkin's lymphomas (cHL) display multiple and concurrent alterations in different pathways and checkpoints of the cell cycle. However, the expression of cyclin D2 and its relation to other major cell cycle proteins has not been analyzed in cHL. The aim of the present study was to assess expression of cyclin D2, Ki67, cyclin A, cyclin B1, cyclin D1, cyclin D3, cyclin E, p53, Rb, p16 and p27 proteins in order to gain further insight into the proliferation profile of cHL. Overexpression of cyclin D2 in Hodgkin's and Reed-Sternberg cells was detected in 64/89 (72%) cases of cHL. This finding, in view of recent in vitro data showing that constitutive activation of nuclear factor (NF)-kB could upregulate cyclin D2 expression in part via signal transducer and activator of transcription (STAT)-5a, suggests that induction of cyclin D2 expression may support the proliferation of Hodgkin's and Reed-Sternberg cells. In addition, the present study showed that (1) increased p27 expression status was significantly correlated with higher levels of cyclin A expression (P=0.048) and (2) increased p53 expression status was significantly correlated with higher levels of cyclin A (P<0.001) and cyclin B1 (P=0.040) expression. The association between increased p27 and p53 expression status and higher expression levels of G2/M cyclins suggests that the impairment of the growth inhibitory activity of the p27 and p53 tumor suppressor pathways may promote the proliferation of Hodgkin's and Reed-Sternberg cells.

A mathematical model of the effects of hypoxia on the cell-cycle of normal and cancer cells

The evolution of the cell-cycle is known to be influenced by environmental conditions, including lack of extracellular oxygen (hypoxia). Notably, hypoxia appears to have different effects on normal and cancer cells. Whereas both experience hypoxia-induced arrest of the G1 phase of the cell-cycle (i.e. delay in the transition through the restriction point), experimental evidence suggests that only cancer cells undergo hypoxia-induced quiescence (i.e. the transition of the cell to a latent state in which most of the cell functions, including proliferation, are suspended). Here, we extend a model for the cell-cycle due to Tyson and Novak (J. Theor. Biol. 210 (2001) 249) to account for the action of the protein p27. This protein, whose expression is upregulated under hypoxia, inhibits the activation of the cyclin dependent kinases (CDKs), thus preventing DNA synthesis and delaying the normal progression through the cell-cycle. We use a combination of numerical and analytic techniques to study our model. We show that it reproduces many features of the response to hypoxia of normal and cancer cells, as well as generating experimentally testable predictions. For example our model predicts that cancer cells can undergo quiescence by increasing their levels of p27, whereas for normal cells p27 expression decreases when the cellular growth rate increases.

Towards whole-organ modelling of tumour growth

Multiscale approaches to modelling biological phenomena are growing rapidly. We present here some recent results on the formulation of a theoretical framework which can be developed into a fully integrative model for cancer growth. The model takes account of vascular adaptation and cell-cycle dynamics. We explore the effects of spatial inhomogeneity induced by the blood flow through the vascular network and of the possible effects of p27 on the cell cycle. We show how the model may be used to investigate the efficiency of drug-delivery protocols.

Retinoblastoma protein is frequently absent or phosphorylated in anaplastic large-cell lymphoma

The possible role of retinoblastoma protein (Rb) in the pathogenesis of anaplastic large-cell lymphoma (ALCL) is unknown. We investigated Rb protein expression, both total (phosphorylated and underphosphorylated) and active (underphosphorylated), in four anaplastic lymphoma kinase (ALK)-positive ALCL cell lines (Karpas 299, JB-6, SU-DHL1, and SR-786) by Western blot analysis, and in 67 ALCL tumors (30 ALK-positive, 37 ALK-negative) using immunohistochemical methods. We also used fluorescence in situ hybridization and polymerase chain reaction methods to assess for loss of heterozygosity of the rb gene. The findings were correlated with apoptotic rate assessed by the terminal dUTP nick-end labeling assay. Immunoblots showed high total Rb levels in Karpas 299, SU-DHL1 and SR-786 and relatively lower levels in and JB-6. Underphosphorylated Rb was negative or expressed at low levels in all cell lines. In ALCL tumors, total Rb was detected in 44 (66%) and absent in 23 (34%). The mean apoptotic rate was 3.2% in Rb-negative tumors compared with 2.7%, 2.2%, and 1.2% in tumors with <10%, 10 to 50%, and >50% Rb-positive cells, respectively (P = 0.2, Kruskall-Wallis test). In a subset of 25 total Rb-positive tumors we assessed for underphosphorylated Rb, which was detected in 12 tumors. The detection of only total Rb in the remaining 13 tumors suggests that Rb was phosphorylated. Fluorescence in situ hybridization showed allelic loss of the rb gene in 10 (40%) of 25 tumors analyzed and was significantly associated with absence of Rb expression (P = 0.003). Similar results were obtained for loss of heterozygosity of the 13q14 locus. Five-year progression-free survival for patients with Rb-negative ALCL was 89.4% compared with 47.7% for patients with total Rb-positive ALCL (P = 0.006, log-rank test). Similar trends for progression-free survival held true for patients with ALK-positive and ALK-negative tumors analyzed separately. In conclusion, Rb is absent or phosphorylated in most ALCL cell lines and tumors and absence of Rb expression is associated with better clinical outcome in patients with ALCL.

Diffuse large B-cell lymphomas with germinal center B-cell-like differentiation immunophenotypic profile are associated with high apoptotic index, high expression of the proapoptotic proteins bax, bak and bid and low expression of the antiapoptotic protein bcl-xl

The aim of this study was to analyze the relations between differentiation immunophenotypes and the status of apoptosis and proliferation in diffuse large B-cell lymphomas. Therefore, the bcl6/CD10/MUM1/CD138 differentiation immunophenotypic profiles were studied in relation to (a) the apoptotic index, (b) the apoptosis-associated bcl2 family proteins bcl2, bcl-xl, bax, bak, bad and bid, (c) the proliferation index (Ki67) and (d) the cell cycle proteins cyclin A, cyclin B1, cyclin D3, cyclin E, p53, Rb, p16 and p27 in 79 cases of diffuse large B-cell lymphomas. Two major differentiation immunophenotypic profiles were distinguished: the germinal center B-cell-like profile; 31 cases (bcl6+/CD10+/-/MUM1-/CD138-: 29 cases and bcl6-/CD10+/MUM1-/CD138-: two cases) and the nongerminal center B-cell-like profile (bcl6+/-/CD10-/MUM1+/CD138-); 48 cases. The expression of bax, bak and bid and the apoptotic index were significantly higher in the germinal center B-cell-like profile than in the nongerminal center B-cell-like profile (P=0.045, 0.018, 0.003 and 0.034, respectively). In contrast, the expression of bcl-xl was significantly lower in the germinal center B-cell-like profile than in the nongerminal center B-cell-like profile (P=0.026). The expression of bcl6 and CD10 showed significant positive correlation with the expression of bax (r=0.659, P<0.001 and r=0.240, P=0.033, respectively), bak (r=0.391, P<0.001 and r=0.233, P=0.039, respectively) and bid (r=0.652, P<0.001 and r=0.238, P=0.035, respectively) and significant negative correlation with the expression of bcl-xl (r=-0.536, P<0.001 and r=-0.250, P=0.029, respectively). The expression of MUM1 showed significant negative correlation with the expression of bax (r=-0.276, P=0.014) and bid (r=-0.266, P=0.018) and significant positive correlation with the expression of bcl-xl (r=0.238, P=0.037). The above findings indicate that diffuse large B-cell lymphomas with germinal center B-cell-like immunophenotypic profile are associated with increased apoptosis status, high expression of the proapoptotic proteins bax, bak and bid and low expression of the antiapoptotic protein bcl-xl.

Promoter hypermethylation and protein expression of the p16 gene: analysis of 43 cases of B-cell primary gastric lymphomas from China

The p16 (CDKN2a/INK4a) gene is an important tumor-suppressor gene, involved in the p16/cyclin-dependent kinase/retinoblastoma gene pathway of cell cycle control. The p16 protein is considered to be a negative regulator of the pathway. Promoter hypermethylation resulting in inactivation of the p16 gene has been found in various hematopoietic malignancies, including non-Hodgkin's lymphoma, and may play a role in transformation/clinical aggressiveness of those tumors. However, the p16 protein expression in primary gastric lymphoma has not been studied. In this study, we characterize protein expression and promoter hypermethylation of the p16 gene in B-cell primary gastric lymphomas from China. In all, 43 cases of B-cell primary gastric lymphoma were investigated. They consisted of 24 (56%) cases of diffuse large-cell lymphoma, 12 (28%) cases of extranodal marginal zone lymphoma, six (14%) cases of extranodal marginal zone lymphoma with large-cell transformation and one (2%) case of follicular lymphoma. Loss of p16 protein expression was found in 34 (79%) out of 43 cases, while the remaining nine (21%) cases showed positivities for the p16 protein. All 43 cases were further characterized by methylation-specific polymerase chain reaction (PCR) to analyze p16 promoter hypermethylation status. In total, 11 (26%) of 43 cases were positive for p16 promoter hypermethylation. Among those, 10 (30%) out of the 33 cases negative for the p16 immunostaining showed promoter hypermethylation, whereas only one (10%) out of the 10 cases that were positive for the p16 immunostaining displayed promoter hypermethylation. Of the 43 cases, 30 had limited pathologic data at the time of resection. Primary gastric lymphoma involved extragastric sites (lymph node or liver) in 17 (57%) of 30 cases, while the remaining 13 (43%) cases were only limited to the stomach. Loss of p16 protein expression was found in 14 (82%) of 17 cases with extragastric involvement and in 11 (85%) of 13 cases without such involvement. In conclusion, loss of p16 protein expression is frequent in those B-cell primary gastric lymphomas and approximately one-third of such loss correlated with promoter hypermethylation. Despite limited pathologic data, loss of p16 protein expression appears not to be correlated with extragastric involvements.

Expression of the Components of the Cip/Kip Family in Malignant Lymphoma of the Thyroid

OBJECTIVE

For evaluating the characteristics of human neoplasms, investigation of regulators of cell cycle progression is important. We studied three components of the Cip/Kip family, p57, p27 and p21, in malignant lymphomas of the thyroid.

METHODS

We immunohistochemically investigated the expression of the three proteins for 49 cases of thyroid lymphomas, as well as 10 cases of chronic thyroiditis.

RESULTS

In infiltrating lymphocytes in chronic thyroiditis, p57 and p27 were diffusely expressed, whereas p21 immunoreactivity was only occasionally observed. In lymphoma, decreased expression of p57 (less than 50% of lymphoma cells were positive) was observed in 24 cases (49.0%). p57 expression was inversely linked to the MIB-1 labeling index, grade of malignancy and aberrant p53 expression. Decreased expression of p27 was observed in 25 cases (51.0%), which was also related to the MIB-1 labeling index and aberrant p53 expression. On the other hand, p21 expression was occasional, and when the cut-off value was set at 3%, 38 cases (77.6%) were regarded as negative. P21 expression was not linked to any clinicopathological parameters.

CONCLUSION

These findings suggest that, among the 3 components of the Cip/Kip family, p57 and p27 play a role in negatively regulating the cell proliferation of thyroid lymphoma cells and decreased expression of them contributes to the progression of this disease.

Prognostic significance of the F-box protein Skp2 expression in diffuse large B-cell lymphoma

The F-box protein Skp2 positively regulates the G1-S transition by promoting degradation of the cyclin-dependent kinase inhibitor p27(kip1) (p27). Recent evidence has suggested an oncogenic role of Skp2 in not only carcinogenesis but also lymphomagenesis. In this study, we performed immunohistochemical analysis on the cell-cycle-associated proteins, Skp2, p27, and Ki-67, in 27 patients with de novo diffuse large B-cell lymphoma (DLBCL), evaluating the correlation between the clinical characteristics and expression levels of these proteins. The patients were classified into two groups according to the positivity for Skp2 expression: a high Skp2 expression group (>60% positive for Skp2 in lymphoma cells) and a low Skp2 expression group (< or = 60%). A high level of Skp2 expression significantly correlated with advanced clinical stage (P = 0.029), although the increase did not correlate with age, gender, LDH levels, presence of extranodal disease, or performance status and resulted in no correlation with the International Prognostic Index-based risk grading. However, it was noteworthy that the high Skp2 expression group demonstrated a significantly worse prognosis than the low Skp2 expression group (P = 0.0007). The expression level of Skp2 correlated with that of Ki-67 but not necessarily with that of p27. The p27 expression level did not correlate patients' prognosis. Taken together, it was suggested that Skp2 was a valuable and independent marker predicting the outcome in DLBCL.

Increased expression of the bcl6 and CD10 proteins is associated with increased apoptosis and proliferation in diffuse large B-cell lymphomas

There is increasing evidence that bcl6 and CD10 expression may be related to apoptosis and cell cycle progression. Therefore, 79 cases of de novo diffuse large B-cell lymphomas were studied for the expression of bcl6 and CD10 proteins in relation to 1) the apoptotic index; 2) the proliferation-associated proteins Ki67, cyclin A, and cyclin B1; and 3) the expression of the bcl2, p53, Rb, p16, and p27 proteins. Expression of bcl6, CD10, and bcl2 proteins was found in 54/79 (68%), 28/79 (35%), and 47/74 (63%) cases, respectively. The bcl6/CD10 patterns were as follows: bcl6+/CD10+ (26 cases, 32%), bcl6+/CD10- (28 cases, 33%), bcl6-/CD10- (23 cases, 31%), and bcl6-/CD10+ (2 cases, 4%). Significant positive correlations were found between bcl6/Ki67 (r =.328, P =.003), bcl6/cyclin A (r =.265, P =.018), bcl6/apoptotic index (r =.327, P =.010), CD10/Ki67 (r =.296, P =.008), and CD10/apoptotic index (r =.397, P =.001). In addition, high expression of bcl6 showed significant correlation with negative (null/low) bcl2 expression (chi(2) test, P =.002). The above findings indicate that increased expression of the bcl6 and CD10 proteins is associated with increased apoptosis and proliferation in diffuse large B-cell lymphomas. The association between increased bcl6 expression and enhanced apoptosis might be due, at least in part, to the null/low bcl2 expression because previous in vitro data showed that bcl6 overexpression induces apoptosis accompanied by bcl2 and bcl-xl downregulation. Moreover, significant correlation was found between increased apoptotic index and the bcl6+/CD10+ pattern (t test: P =.014, Mann-Whitney test: P =.046). This finding and the positive correlation of the apoptotic index with bcl6 and CD10 expression may be related to previous results showing that the expression of these proteins has favorable effects on the clinical outcome of diffuse large B-cell lymphomas.