The expression and prognostic significance of Cks1 in salivary cancer

Cks1 is an essential factor in facilitating Skp2-dependent degradation of p27, but its role in salivary malignancies is unknown. Expression of cyclin-dependent kinase subunit 1 (Cks1) was examined in 64 salivary malignancies, compared with p27, S-phase kinase protein 2 (Skp2), Ki-67, p53, and TDT-mediated dutp-biotin nick end labeling (TUNEL) expression, and with THE patient's clinical and pathological parameters. Cks1 expression was markedly increased in 30 patients (47%) and strongly correlated with increased expression of Skp2, Ki-67, p53, and TUNEL, but inversely with p27 levels. High expression of Cks1 WAS strongly associated with lymph node metastases and poor prognosis and survival. Cks1 alterations may have a significant biological role in the pathogenesis of salivary cancer.

The salivary tip of the p53 mutagenesis iceberg: novel insights

Salivary malignancies are rare, heterogeneous, unpredictable in their clinical behavior and seldom studied. This study focused on examining the expression of mutated p53, the most prevalent mutated gene related to human cancer, in a rather large cohort of salivary malignancies (n = 70) and for a prolonged period (20 years). P53 was found to be a most powerful predictor for poor survival and more so when the tumor concurrently expressed TUNEL and heparanase markers, dramatically dropping the survival probability of the patients to 0! Survival probability at 6 years for patients with tumors stained negatively vs. positively for p53, TUNEL and heparanase was 100% vs. 49% while at 18 years this probability dropped to 67% vs. 0%, respectively (p = 0.023). Significant correlation rates were found between age and poor survival, age and p53, and p53 and other co-existing malignancies. These findings support mutated p53 as a prognostic predictor and a pivotal player in salivary carcinogenesis. Significantly more extensive therapy applied to salivary p53-positive patients did not improve mortality rate, questioning the justification for such extensive therapy and emphasizing the need to understand p53, TUNEL and heparanase biological pathways and develop additional therapeutic tools for fighting salivary cancer.

p27 and salivary cancer

This study examined p27 expression in a cohort of salivary malignancies (n = 74) for a prolonged period (20 years). Reduction of p27 expression was found to be a most powerful predictor for poor survival and more so when the tumor concurrently expressed high levels of p53, TUNEL and heparanase markers, dramatically dropping the patient survival probability to 0! While no patient whose tumor-staining profile included: p27 > 50%, p53 = 0, TUNEL = 0 and heparanase = 0, died of the disease during the 20-year follow up, the median of survival of the group with p27 0, TUNEL > 0 and heparanase > 0 was only 39 months. The survival probabilities of these two groups at 5 years were 100 and 50%, respectively, and at 20 years they were 100 and 0%, respectively (P = 0.05). Significant p27 reduction also resulted in significantly larger tumor size (T value), higher spread of neck metastasis and extra capsular spread and in more advanced disease (higher stage). Significant correlation rates were found between age and poor survival, age and reduced p27 expression, and reduced p27 expression and other general co-existing malignancies, indicating p27 reduction as part of a general phenomenon-age related mutagenesis. Significantly more extensive therapy applied to patients with salivary reduced-p27 tumors could not prevent the rise in mortality rate, questioning the justification for extensive therapy which is naturally accompanied by higher morbidity. Additional therapeutic tools for fighting salivary cancer, possibly based on the new understanding of the p27, p53, TUNEL and heparanase carcinogenic network, are necessary.

Skp2 and salivary cancer

Salivary malignancies are rare, heterogeneous, unpredictable in clinical behavior and seldom studied. Skp2 expression was examined in salivary malignancies (n = 75) for a prolonged period (20 years). In 40/75 (53%) cases Skp2 expression rate (staining level) was < or =4% while in the remainder (47%) it was >4%. Correlation between enhanced Skp2 and enhanced p53 staining levels was significant (p = 0.042), as were correlation rates between enhanced Skp2 and reduced p27 staining levels (p = 0.01) and enhanced Skp2 and enhanced TUNEL staining levels (p = 0.008). Survival probability rates dropped when Skp2 expression increased. Median patient survival for reduced-stained-tumor patients (< or =4%) was 143 months and significantly lower, 49 months (p = 0.016), for enhanced-stained-tumor patients (>4%). Survival probability at 5 years was 82% for the former group (< or =4%) and 47% for the latter (>4%). At 20 years, survival dropped to 35% and 18% respectively (p = 0.016). More extensive and aggressive therapy did not reduce mortality in patients with enhanced Skp2-expressing tumors. Significant correlations between poor survival and significantly altered expression rates of Skp2, p27, p53, TUNEL and heparanase in salivary malignancies, suggest a biological role in salivary cancer pathogenesis for these 5 markers. The findings may be used for prognostic and follow-up purposes.

Ki67 and salivary cancer

We examined Ki67 expression in salivary malignancies of 75 patients with a follow-up period of up to 20 years. Correlations between enhanced Ki67 and enhanced p53 and TUNEL and heparanase staining levels were significant. Median survival for reduced-stained-tumor patients (< or = 5%) was 163 months, dropping significantly to 39 months (p = 0.0005) for enhanced stained tumors (> 5%); 5 year survival probability was 93% and 33%, respectively, 45% and 16%, respectively, (p = 0.0005) at 20 years. Significant correlation between poor survival and concurrently altered expression rates of Ki67 and p53, p27 Skp2, TUNEL and heparanase in the salivary malignancies indicates a biological role in salivary cancer pathogenesis.

Heparanase is overexpressed in lung cancer and correlates inversely with patient survival

BACKGROUND

Heparanase is an endo-beta-D-glucuronidase that is capable of cleaving heparan sulfate (HS) side chains at a limited number of sites, yielding HS fragments of still appreciable size (approximately 5-7 kDa). Heparanase activity has been detected frequently in several cell types and tissues. Heparanase activity correlates with the metastatic potential of tumor-derived cells, a correlation that has been attributed to enhanced cell dissemination as a consequence of HS cleavage and remodeling of the extracellular matrix barrier.

METHODS

In this study, the authors examined heparanase expression in 114 patients with lung cancer by means of immunohistochemistry and correlated clinical-pathologic data with heparanase immunostaining and cellular localization.

RESULTS

Heparanase was overexpressed in 75% of the study patients. Heparanase expression was correlated with lung cancer lymph node status and metastasis classification (P = .04 and P = .01, respectively) and was correlated inversely with patient survival (P = .007). It is noteworthy that this adverse effect depended largely on the cellular localization of heparanase. Thus, whereas cytoplasmic staining of heparanase is associated with a poor prognosis, nuclear heparanase predicts a favorable outcome for patients with lung cancer.

CONCLUSIONS

The current findings suggest that heparanase expression and cellular localization are decisive for lung cancer patients' prognosis, most likely because of heparanase-mediated tumor cell dissemination by blood and lymph vessels.

TUNEL as a tumor marker of tongue cancer

Squamous cell carcinoma (SCC) of the tongue has an increasing incidence, a high morbidity rate and a 50% 5-year mortality rate. We analyzed the rate of apoptosis using TDT-mediated dUTP-biotin nick end-labeling (TUNEL), p53 and heparanase in 73 patients with tongue cancer by immonohistochemistry, and tested data for correlation with survival, tumor size, grade and metastasis. TUNEL staining was strong in 54% of the tumors; the remainder lacked staining, as did all healthy control tissues. Significant correlations were found between TUNEL staining level and p53 expression rates (p=0.016) and between TUNEL and heparanase (p=0.039). Moreover, while the cumulative 5-year survival probability for tumors not stained for TUNEL and p53 was 63%, but dropped to 34% with TUNEL staining; for lack of TUNEL and heparanase (=0), 5-year survival rate was 50%, while staining presence (>0) reduced survival to 34%. TUNEL joins other biomarkers in indicating prognosis of understanding pathogenesis of tongue cancer.

Over-expression of Skp2 is associated with resistance to preoperative doxorubicin-based chemotherapy in primary breast cancer

INTRODUCTION

Preoperative chemotherapy is often used in patients with locally advanced breast cancer. However, commonly used clinical and pathological parameters are poor predictors of response to this type of therapy. Recent studies have suggested that altered regulation of the cell cycle in cancer may be involved in resistance to chemotherapy. Over-expression of the ubiquitin ligase Skp2 results in loss of the cell cycle inhibitor p27Kip1 and is associated with poor prognosis in early breast cancer. The purpose of the present study was to examine the role of these proteins as predictors of clinical outcome and response to chemotherapy in locally advanced breast cancer.

METHODS

The expression levels of Skp2 and p27Kip1 were determined by immunohistochemistry both before and after preoperative chemotherapy in 40 patients with locally advanced breast cancer. All patients were treated with cyclophosphamide/doxorubicin (adriamycin)/5-fluorouracil (CAF) and some patients received additional treatment with docetaxel. Expression data were compared with patients' clinical and pathological features, clinical outcome, and response to chemotherapy.

RESULTS

Skp2 expression before preoperative chemotherapy was inversely related to p27Kip1 levels, tumor grade, and expression of estrogen and progesterone receptors. Both Skp2 and p27Kip1 were found to be accurate prognostic markers for disease-free and overall survival. High preoperative expression of Skp2 was associated with resistance to CAF therapy in 94% of patients (P < 0.0001) but not with resistance to docetaxel.

CONCLUSION

Skp2 expression may be a useful marker for predicting response to doxorubicin-based preoperative chemotherapy and clinical outcome in patients with locally advanced breast cancer.

Heparanase up-regulation in tongue cancer: tissue and saliva analysis

BACKGROUND

Heparanase up-regulation has been correlated with reduced postoperative survival in various cancers.

METHODS

Heparanase expression was analyzed in 60 consenting tongue (mobile) cancer patients by means of immunohistochemistry. Heparanase levels were also analyzed in the saliva of both healthy controls and tongue cancer patients using a novel heparanase enzyme-linked immunosorbent assay method.

RESULTS

Heparanase staining was positive (>0) in 92% and negative (=0) in 8% of the tumors and staining intensity correlated with tumor size and tumor stage. Moreover, the survival probability of patients negative for heparanase (=0) at 60 months was 100%, compared with only 41% for patients positive for heparanase (>0), suggesting that heparanase may serve as a prognostic factor for this malignancy and an attractive target for anticancer drug development. Heparanase was detected in the saliva of healthy controls and the mean concentration was determined as 119 +/- 37 pg/mL. Importantly, a nearly 3-fold increase of heparanase levels was detected in saliva collected from tongue cancer patients (334 +/- 69 pg/mL), a difference that is statistically highly significant (P = .004).

CONCLUSIONS

These findings support heparanase up-regulation in tongue cancer and raise the possibility of using this simple test as a diagnostic tool to monitor tongue cancer progression and response to treatment.

Regulation of the cell cycle inhibitor p27 and its ubiquitin ligase Skp2 in differentiation of human embryonic stem cells

Embryonic stem cells combine the features of robust proliferation with precise differentiation capacity. p27 is a cell cycle inhibitor that is involved in the regulation of proliferation and differentiation in many developing tissues. Recent studies in murine embryonic stem cells have suggested that p27 is involved in the progression of normal differentiation programs in these cells. However, the expression and regulation of p27 and its role in the differentiation of human embryonic stem cells (hESc) has not been previously explored. Herein we show that p27 expression was low in undifferentiated hESc, but increased markedly in differentiated cells. The expression of Skp2, the ubiquitin ligase that targets p27 for degradation, was inversely related to p27 expression. Moreover, embryoid bodies (EBs) with low p27 expression and high Skp2/p27 ratio showed poorer differentiation than those with high p27 expression. Modulation of Skp2 expression is mainly regulated by its rate of degradation. In contrast to somatic cells, which have high levels of Skp2 mainly in S and G2/M, in undifferentiated hESc Skp2 levels were also high in G1. These results point to a potentially important role for p27 regulation in hESc.

Downregulation of Sef, an inhibitor of receptor tyrosine kinase signaling, is common to a variety of human carcinomas

Carcinomas are tumors of epithelial origin accounting for over 80% of all human malignancies. A substantial body of evidence implicates oncogenic signaling by receptor tyrosine kinases (RTKs) in carcinoma development. Here we investigated the expression of Sef, a novel inhibitor of RTK signaling, in normal human epithelial tissues and derived malignancies. Human Sef (hSef) was highly expressed in normal epithelial cells of breast, prostate, thyroid gland and the ovarian surface. By comparison, substantial downregulation of hSef expression was observed in the majority of tumors originating from these epithelia. Among 186 primary carcinomas surveyed by RNA in situ hybridization, hSef expression was undetectable in 116 cases including 72/99 (73%) breast, 11/16 (69%) thyroid, 16/31 (52%) prostate and 17/40 (43%) ovarian carcinomas. Moderate reduction of expression was observed in 17/186, and marked reduction in 40/186 tumors. Only 13/186 cases including 12 low-grade and one intermediate grade tumor retained high hSef expression. The association of hSef downregulation and tumor progression was statistically significant (P<0.001). Functionally, ectopic expression of hSef suppressed proliferation of breast carcinoma cells, whereas inhibition of endogenous hSef expression accelerated fibroblast growth factor and epidermal growth factor-dependent proliferation of cervical carcinoma cells. The inhibitory effect of hSef on cell proliferation combined with consistent downregulation in human carcinoma indicates a tumor suppressor-like role for hSef, and implicates loss of hSef expression as a common mechanism in epithelial neoplasia.

TUNEL - an efficient prognosis predictor of salivary malignancies

Biological markers are necessary for predicting prognosis of salivary malignancies and better understanding the pathogenesis of salivary cancer. We analysed terminal deoxynucleotidyl transferase (TdT)-mediated biotinylated deoxyuridine-triphosphate (dUTP)-biotin nick-end labelling (TUNEL), p53 and Ki67 expression in 66 patients with malignant salivary tumours by immonohistochemistry, and correlated the data with survival, disease-free survival, tumour grade, stage, and local and distant metastasis. TUNEL efficiently predicted poor prognosis in salivary malignancies. The 5-year (5Y) survival probability dropped significantly with the level of TUNEL staining (from 83% in negatively stained tumours to 57 and 24% in TUNEL positively stained levels 1 and 2, respectively), (P=0.042). Extensive Ki67 staining (in addition to TUNEL) reduced the 5Y-survival rate even further and addition of positively stained p53 dropped the 5Y-survival rate to 0. The correlation rates between TUNEL and Ki67 was 58% (P=0.0001), and between TUNEL and p53 it was 50% (P=0.035). Concurrently, TUNEL correlated with metastasis, extracapsular spread, grade and stage. The correlation between TUNEL, p53 and Ki67 staining and survival probabilities, and the pathological grade, stage and metastasis spread of salivary malignancies makes this a highly effective tool in patient follow-up and prognosis.

Expression of the ubiquitin ligase subunit cyclin kinase subunit 1 and its relationship to S-phase kinase protein 2 and p27Kip1 in prostate cancer

PURPOSE

Loss of the cell cycle inhibitory protein p27Kip1 in cancer is associated with tumor aggressiveness and poor prognosis in the prostate. The decrease in p27(Kip1) results from increased proteasome dependent degradation, which is mediated by its specific ubiquitin ligase subunits S-phase kinase protein 2 and cyclin dependent kinase subunit 1. S-phase kinase protein 2 was found to be over expressed in aggressive prostate cancers but to our knowledge the role of cyclin dependent kinase subunit 1 in these cancers is unknown.

MATERIALS AND METHODS

The expression of cyclin dependent kinase subunit 1, S-phase kinase protein 2 and p27Kip1 was examined by immunohistochemistry in tissue sections from 45 patients with prostate cancer. The expression of cyclin dependent kinase subunit 1 was compared to that of S-phase kinase protein 2 and p27Kip1, and patient clinical and histological characteristics.

RESULTS

Cyclin dependent kinase subunit 1 expression was strongly associated with S-phase kinase protein 2 expression (r = 0.666, p = 0.001) and inversely with p27Kip1 expression (r = -0.737, p < 0.001). Cyclin dependent kinase subunit 1 over expression was associated with loss of tumor differentiation (r = 0.631, p = 0.001), high serum prostate specific antigen (r = 0.627, p < 0.001) and metastatic disease (p < 0.001).

CONCLUSIONS

These results suggest that cyclin dependent kinase subunit 1 is involved in p27Kip1 down-regulation and it may have an important causative role in the development of aggressive tumor behavior in prostate cancer.

Heparanase upregulation by colonic epithelium in inflammatory bowel disease

Heparanase is an endo-beta-D-glucuronidase capable of cleaving heparan sulfate (HS) side chains at a limited number of sites, yielding HS fragments of still appreciable size ( approximately 5-7 kDa). Heparanase activity has long been detected in a number of cell types and tissues. Importantly, heparanase activity correlated with the metastatic potential of tumor-derived cells, attributed to enhanced cell dissemination as a consequence of HS cleavage and remodeling of the extracellular matrix barrier. Similarly, heparanase activity was implicated in neovascularization, inflammation and autoimmunity, involving migration of vascular endothelial cells and activated cells of the immune system. The involvement of heparanase in inflammatory processes of the gastrointestinal tract has not been examined. Here, we utilized immunohistochemical analysis to investigate heparanase expression in acute and chronic inflammatory conditions. Heparanase expression was not detected in specimens derived from normal colon tissue. In contrast, strong heparanase staining was observed in Crohn's disease and ulcerative colitis, but not in infectious colitis. Interestingly, heparanase staining was primarily observed in epithelial rather than immune cells. Importantly, un-fractionated as well as low molecular weight heparin (enoxaparin), which exhibit a strong inhibitory activity towards heparanase, have proven efficacious in ulcerative colitis and Crohn's disease patients, suggesting that heparanase is actively involved in these pathologies and thus may be considered as a target for the development of anti-inflammatory therapies.

Heparanase expression in malignant salivary gland tumors inversely correlates with long-term survival

BACKGROUND

Upregulation of the endo-beta-D-glucuronidase, heparanase, was noted in an increasing number of human malignancies. Heparanase expression correlated with enhanced local and distant metastatic spread, increased vascular density, and reduced postoperative survival.

PATIENTS AND METHODS

We analyzed heparanase expression in 60 patients (aged 59 +/- 17 years) with malignant salivary tumors (39 males and 21 females) using immunohistochemistry. We applied antiheparanase antibody 733, which has previously been shown to preferentially recognize a 50-kDa active heparanase subunit over a 65-kDa latent enzyme. Thus, immunostaining can directly be correlated with enzymatic activity.

RESULTS

Heparanase staining was positive (> 0) in 70% of tumors (42 of 60 patients) and was negative (0) in the remaining 30% (18 patients). The cumulative survival of patients diagnosed as heparanase-negative (n = 18) at 300 months was 70% (95% confidence interval = 35-88). In contrast, the cumulative survival of patients diagnosed as heparanase-positive (n = 42) at 300 months was 0% (statistically significant difference, P = .035).

CONCLUSIONS

Heparanase expression levels inversely correlate with the survival rates of salivary gland cancer patients, clearly indicating that heparanase is a reliable prognostic factor for this malignancy and an attractive target for anticancer drug development.

Heparanase expression in nasopharyngeal carcinoma inversely correlates with patient survival

AIMS

To determine the expression and prognostic significance of heparanase in nasopharyngeal carcinoma (NPC).

METHODS

Immunohistochemistry was performed on formalin-fixed paraffin-embedded sections of 46 patients with NPC. Clinical and immunohistochemical data were correlated with gender, age, histological type, Epstein-Barr virus (EBV) status, stage and survival.

RESULTS

Heparanase immunoreactivity was found in 35% (16/46) of specimens. The cumulative survival of patients diagnosed as heparanase negative (n = 30) at 10 years was 70%. In contrast, the cumulative survival of patients diagnosed as heparanase positive (n = 16) at 10 years was 25%, differences that are highly statistically significant (P = 0.03). No significant correlations were found between heparanase immunoreactivity and gender, age, EBV status, tumour histology or tumour stage.

CONCLUSION

Heparanase expression is inversely correlated with survival of NPC patients, clearly indicating that heparanase is a reliable prognostic factor for this malignancy, and further supports the notion that heparanase is a valid target for the development of anti-cancer drugs.

Inhibition of basic leucine zipper transcription is a major mediator of atrial dilatation

OBJECTIVE

Atrial fibrillation is the most prevalent clinically significant cardiac arrhythmia. Atrial dilatation, a predictor of atrial fibrillation, is thought to result from increased ventricular pressure. However, the underlying molecular mechanisms responsible for atrial dilatation are largely unknown. Here we sought to examine whether the expression of a basic leucine zipper inhibitor protein, JDP2, in the heart is sufficient for the generation of atrial dilatation.

METHODS

A tetracycline-regulated transgene was used to express JDP2 specifically in the mouse heart. Mice hearts were dissected and subjected to Northern and Western analysis, or analyzed by ECG recording and echocardiography. Regulation of gene expression was studied using electromobility shift assays and luciferase gene reporter analysis.

RESULTS

Expression of JDP2 resulted in massive bi-atrial dilatation, defects in conduction, and a lethal phenotype. These effects were developmentally independent, acquired during adulthood, and were reversible upon abolishing of JDP2 expression. Connexin 40 and myosin light chain 2a expression were identified as potential target genes.

CONCLUSION

Expression of basic leucine zipper transcription inhibitors is sufficient to results in atrial dilatation. This dilatation is acquired postnatally and is reversible. Thus, basic leucine zipper transcription inhibitors may be a relevant therapeutic target for preventing atrial dilatation and atrial fibrillation.

Expression of cell cycle regulatory proteins in ovaries prophylactically removed from Jewish Ashkenazi BRCA1 and BRCA2 mutation carriers: Correlation with histopathology

OBJECTIVES

Prophylactic oophorectomy in Ashkenazi Jewish women with BRCA mutations represents a unique opportunity to search for premalignant changes in ovaries. Reports on the presence of dysplastic lesions in these ovaries are contradictory. Our aim was to study the expression of cell cycle regulatory proteins--p53, Skp2, p27, Ki67, Bcl2 and p16--in correlation with histopathological changes. p16(INK4A) was not studied before in prophylactically removed ovaries.

METHODS

Ninety-four ovaries from 50 Ashkenazi Jewish BRCA carriers were compared with 42 ovaries removed for reasons unrelated to cancer and with 16 ovarian carcinomas.

RESULTS

Three (6%) patients from the high-risk group had an occult carcinoma. A significant association was found between BRCA-positive expression and the presence of atypical changes in the superficial ovarian epithelium (P = 0.014) as well as the presence of epithelial cortical clefts (P = 0.042). Expression of p53 in cortical inclusions was significantly higher in the BRCA-positive cases than in the benign control group (P = 0.03). The high-risk and the benign control group did not differ significantly by the expression of p16, BCL2, Ki67, p27 and SKP2 (P > 0.05). However, both groups significantly differed from the carcinoma group (P < 0.0001). A significant positive correlation was found between the expression of Ki67, and the grade of atypia in the high-risk group (R = 0.3, P = 0.01) and in the benign control group (R = 0.5, P = 0.02).

CONCLUSIONS

BRCA mutation carriers had more atypical changes in the superficial epithelium (P = 0.014) and more epithelial cortical clefts (P = 0.042) compared to the benign control group. The histopathology changes were not supported by significantly altered expressions of the proteins used in our study. Additional molecular studies could contribute to the disclosure of precancerous ovarian lesions.

Pediatric nasopharyngeal carcinoma: better prognosis and increased c-Kit expression as compared to adults

INTRODUCTION

Nasopharyngeal carcinoma (NPC) in children is distinguishable from the adult form by its close association with Epstein-Barr virus (EBV) infection, a higher rate of undifferentiated histology, and a greater incidence of advanced locoregional disease.

PATIENTS AND METHODS

Sixteen NPC patients, < or =20 years of age were identified from our 1976-2001 tumor registry records. Clinical stage, treatment, recurrence, and survival were evaluated. Sections were stained by immunohistochemistry for p53, Bcl-2, Ki67, and c-Kit and by in situ hybridization for EBER. Obtained data were compared to 32 adult patients. All patients had undifferentiated or non-keratinizing NPC.

RESULTS

EBER was positive in 100% of children, compared to 90% of adults. Comparing children to adults, median Ki67 index was 49% and 30%, p53 positive tumors were 69% and 94%, positive Bcl-2 was 63% and 72%, and positive c-Kit was 88% and 28%, respectively.

CONCLUSION

No parameter had significant predictive values for survival, although c-Kit expression had a trend for better prognosis in the pediatric group. By univariate analysis of all 48 cases, positive c-Kit was associated with better survival (P = 0.029), largely due to the better survival of the pediatric group. By multivariate analysis, increased stage (P = 0.006) and older age (P = 0.044) correlated with worse prognosis.

Oropharyngeal cancer pathogenesis: Ubiquitin proteolytic, apoptotic and epidermal growth factor related pathways act in concert—first report

The current study was carried out to examine the clinical characteristics and survival-probability rates of 51 patients treated for oral (tongue) cancer and to correlate it with various tumor markers. The clinical data and survival probability rates were correlated with the immunohistological analysis of p27, Skp2, p53, Bcl-2, TUNEL (apoptotic rate) and c-erbB-2 markers. The 5-year survival-probability correlated with staging, grading and base of tongue location. An inverse relation between the expression of p27 and Skp2, p27 and grading, and a direct relation between Skp2 and grading were demonstrated. Concomitantly, significant correlations between low p27, high Skp2 and high TUNEL (apoptotic rate) expressions and between low p27 and high c-erbB-2 (Her2) expressions in the cancer lesions were demonstrated. The accumulated data may be employed in the future for a better understanding of the biology behind oral cancer and for developing better means of detection and treatment.

The expression of the ubiquitin ligase subunit Cks1 in human breast cancer

Introduction

Loss of the cell-cycle inhibitory protein p27^Kip1 is associated with a poor prognosis in breast cancer. The decrease in the levels of this protein is the result of increased proteasome-dependent degradation, mediated and rate-limited by its specific ubiquitin ligase subunits S-phase kinase protein 2 (Skp2) and cyclin-dependent kinase subunit 1 (Cks1). Skp2 was recently found to be overexpressed in breast cancers, but the role of Cks1 in these cancers is unknown. The present study was undertaken to examine the role of Cks1 expression in breast cancer and its relation to p27^Kip1 and Skp2 expression and to tumor aggressiveness.

Methods

The expressions of Cks1, Skp2, and p27^Kip1 were examined immunohistochemically on formalin-fixed, paraffin-wax-embedded tissue sections from 50 patients with breast cancer and by immunoblot analysis on breast cancer cell lines. The relation between Cks1 levels and patients' clinical and histological parameters were examined by Cox regression and the Kaplan–Meier method.

Results

The expression of Cks1 was strongly associated with Skp2 expression (r = 0.477; P = 0.001) and inversely with p27^Kip1 (r = -0.726; P < 0.0001). Overexpression of Cks1 was associated with loss of tumor differentiation, young age, lack of expression of estrogen receptors and of progesterone receptors, and decreased disease-free (P = 0.0007) and overall (P = 0.041) survival. In addition, Cks1 and Skp2 expression were increased by estradiol in estrogen-dependent cell lines but were down-regulated by tamoxifen.

Conclusion

These results suggest that Cks1 is involved in p27^Kip1 down-regulation and may have an important role in the development of aggressive tumor behavior in breast cancer.

Increased renal hypertrophy in diabetic mice genetically modified at the haptoglobin locus

BACKGROUND

The human haptoglobin (Hp) gene is polymorphic with two functional classes of alleles, denoted 1 and 2. We have demonstrated in three longitudinal studies and several cross-sectional studies that the Hp genotype is an independent risk factor for diabetic vascular disease. These studies have presented a compelling argument that diabetic individuals homozygous for the Hp 1 allele are at decreased risk of vascular complications as compared to diabetic individuals with the Hp 2 allele.

METHODS

The naturally occurring (wild type) mouse Hp is a class 1 Hp allele. We examined renal hypertrophy in wild-type mice, Hp knockout mice (Hp 0), and in mice with the Hp 2 allele (Hp 2) with and without diabetes.

RESULTS

In the absence of diabetes, we found that renal hypertrophy was significantly increased in Hp 0 mice and that this could be prevented with vitamin E. There was no difference between wild type and Hp 2 mice with regard to renal hypertrophy in the absence of diabetes. However, in the presence of diabetes, Hp 2 mice demonstrated a significant increase in renal hypertrophy as compared to wild-type mice.

CONCLUSIONS

These results support a direct linkage between diabetic vascular disease and the Hp genotype. These Hp-modified mice may serve as a platform on which to test a variety of pharmacological agents in order to decrease diabetic vascular disease.

Low-grade renal collecting duct carcinoma. A case report with histochemical, immunohistochemical, and ultrastructural study

We report a rare tumor called low-grade renal collecting duct carcinoma. Grossly, the tumor consisted of multiple cysts and solid white nodules, measuring 10 cm in diameter and occupying most of the renal parenchyma. Histologically, the tumor was characterized by well-differentiated tubules lined by eosinophilic cells without papillary projections, abundant predominantly extracellular mucin, minimal cellular atypia, no desmoplasia, and rare mitoses. This tumor occurs in collecting ducts and the tumor cells were positive for epithelial membrane antigen, high-molecular-weight keratin, CD15, and mitochondrial antibody and negative for CD10. Few cells stained weakly positive for ulex europaeus. Ultrastructural study showed a large number of mitochondria according to the eosinophilic cells seen in light microscopy.