Cell proliferation and p53 protein expressions in cutaneous epithelial neoplasms

We investigated correlations between cell proliferation, p53 overexpression, and degree of malignancy in cutaneous epithelial neoplasms. One hundred and fourteen cases of epithelial neoplasms, including seborrheic keratosis (SEB), basal cell carcinomas (BCCs), solar keratosis (SK), Bowen's disease (BD), and squamous cell carcinomas (SCCs) were examined using argyrophilic nucleolar organizer region (AgNOR) staining. In addition, immunohistochemical analysis using the Ki-67 (MIB-1) and anti-p53 (DO-7) monoclonal antibodies was performed. The ratio of tumorous to normal cells according to AgNOR staining was defined as the AgNOR rate, and the ratio of tumorous to normal cells according to Ki-67 recognition was defined as the Ki-67 rate. SCC lesions showed the highest AgNOR rate among the investigated epithelial neoplasms, followed in order by BD, BCC, SK, and SEB lesions. The Ki-67 rate was highest in BD lesions, followed in order by SK, SCC, BCC, and SEB lesions. Expression of p53 protein was highest in SK lesions. SCC is generally considered to be the most malignant neoplasm, followed in order by BCC, BD, and SK. Thus, our results suggest that the Ki-67 rate and overexpression of p53 protein do not always reflect the degree of malignancy in neoplasms.     

A phase II trial of weekly infusional 5-fluorouracil in combination with low-dose leucovorin in patients with advanced colorectal cancer

We examined 59 breast cancers for p53 and bcl-2 protein expression by immunohistochemistry. The results were correlated with Ki-67 immunostaining. p53-negativity was noted in 40 cases and the remaining 19 tumours were p53-positive. Thirty-six tumours showed strong expression of bcl-2 and in 23 no staining for this protein was observed. We found statistically significant reverse correlation between expression of p53 and bcl-2 in majority of carcinomas: 31 cases were bcl-2 positive and p53-negative, and 14 tumours were bcl-2-negative and p53-positive. Six carcinomas showed no nuclear staining for Ki-67 and in the remaining 53 the percent of cancer cells positive for Ki-67 ranged from 1 to 60 (mean: 14.6). In these 53 cases we found that bcl-2-positive tumours were characterized by lower proliferation than bcl-2-negative tumours, the mean value of Ki-67 immunostaining being 10.7% and 23.0%, respectively. p53-negative tumours showed lower proliferation than p53-positive tumours: mean Ki-67 index was 10.2% and 23.9%, respectively. We conclude that immunohistochemically detected p53 and bcl-2 proteins show a significant inverse relationship in majority of breast carcinomas and their expression correlates with tumour proliferation (Ki-67 immunostaining).     

Differential expression of cell survival and cell cycle regulatory proteins in cutaneous squamoproliferative lesions

Previous models of cutaneous carcinogenesis have primarily focused on the regulation of keratinocyte (KC) proliferation and differentiation. However, it has become clear in many neoplastic systems that altered rates of cell death and/or inability to undergo growth arrest can also contribute to the development of cancer. Apoptosis-regulatory proteins include those that block apoptosis such as Bcl-2 and Bcl-x, whilst a related protein Bax promotes apoptosis. Cell cycle regulatory proteins include those associated with growth arrest, i.e. p21wafl, p53, and those associated with proliferation, i.e. Ki-67. Paraffin embedded samples from ten different lesions of squamous cell carcinoma (SCC), Bowen's disease (BD), keratoacanthomas (KA), and nine normal adult skin samples were stained by immunohistochemistry to detect expression of Bcl-2, Bcl-x, Bax, Ki-67, p21wafl, p53 and apoptosis (TUNEL assay). Compared to low levels of Bcl-x and Bcl-2 immunostaining in normal skin, all the squamoproliferative lesions had strong and diffuse KC expression of Bcl-x (>80%) but minimal to absent KC Bcl-2 expression (<15%). Bax immunopositivity was limited to the basal layer in normal skin and BD. In contrast, by examining serial sections both Bcl-x and Bax appeared to be coexpressed by the majority of malignant KCs in KA and SCC (>70%). These immunostaining profiles reveal that squamoproliferative lesions, including invasive transformed KCs, preferentially express Bcl-x over Bcl-2, in addition to upregulating their Bax levels. Even though there were numerous TUNEL positive cells in these squamoproliferative lesions, no other evidence of apoptosis was seen reinforcing the necessity to use caution when relying on TUNEL staining for identification of programmed cell death in skin biopsies. Normal sun-exposed skin had low but detectable p53 and rare p21wafl KC expression. Significantly higher numbers of p21wafl and p53 immunopositive KCs were noted throughout the lesions in BD and SCC in contrast to KA where p53 and rare p21wafl immunopositive KCs were primarily limited to the periphery of the tumor cell islands. In general, p53 KC expression was higher in all squamoproliferative lesions and sun-exposed normal skin compared to p21Wafl expression. Summary of the expression of cell cycle regulatory proteins for both p21wafl and p53 KC expression was: SCC > BD > KA, in marked contrast to Ki-67 KC expression which was: BD > KA > SCC. The relatively few malignant cells in SCC that were actively participating in the cell cycle (i.e. Ki-67 positive) suggests that these neoplasms may arise primarily by increased cell survival and resistance to apoptosis rather than by hyperproliferation. These studies emphasize the importance of examining multiple members of protein families that regulate apoptosis, proliferation, growth arrest, and differentiation. It is the overall balance between these cellular phenomena that determine whether a cell remains viable or undergoes programmed cell death and contributes to the appearance of a neoplasm. The overexpression of Bcl-x may confer a survival advantage to malignant KCs unable to growth arrest to repair damaged DNA (mutant p53) and/or undergo terminal differentiation (increased p21wafl). Thus, mutation or aberrant expression of such proteins may participate in the multistep process of carcinogenesis that gives rise to these squamoproliferative lesions.     

Distinction of basaloid carcinoma of the prostate from benign basal cell lesions by using immunohistochemistry for bcl-2 and Ki-67

The distinction of rare basaloid carcinomas (BC) of the prostate from more common basal cell hyperplasia may be difficult, because basal cell hyperplasia (BCH) may have prominent nucleoli and may appear infiltrative. Using immunohistochemistry, we studied bcl-2 and p53 expression and Ki-67 proliferation index in eight cases of typical BCH, eight cases of BCH with nucleoli, and six cases of BC. Bcl-2 expression (P < .0001) and Ki-67 index (P=.005) were elevated in BC compared with typical BCH or BCH with nucleoli, whereas there was no significant difference between typical BCH and BCH with nucleoli. P53 was not discriminative in separating benign from malignant basal cell lesions of the prostate. Bcl-2 may play a role in the pathogenesis of basal cell lesions of the prostate. Elevated expression of bcl-2 and higher Ki-67 index may aid in the diagnosis of basal cell proliferative lesions of the prostate.     

The prevalence of bcl-2, p53, and Ki-67 immunoreactivity in transitional cell bladder carcinomas and their clinicopathologic correlates

The aim of this study was to investigate the expression of bcl-2, p53 oncoproteins, and Ki-67 antigen in a series of transitional cell bladder carcinomas and its relation to the traditional prognostic indicators and patient's survival. One hundred six cases with transitional cell carcinoma (TCC) were examined for detection of bcl-2, p53 proteins, and Ki-67 antigen (MIB1 antibody). Bcl-2 immunohistochemical positivity was observed in 52% of TCCs and in 57% of low-grade and 44% of high-grade TCCs. Bcl-2 was also detected in normal urothelium and dysplastic lesions with basal cell expression, and negative staining was observed in carcinomas in situ. Tumor stage showed a significant inverse correlation with overall bcl-2 positivity. The loss of bcl-2 protein expression in higher-stage TCCs was statistically significant (Pt = .01). p53 protein was overexpressed in 50% of TCCs and more frequently in invasive and in carcinomas in situ than in superficial TCCs (Pt = .03). In contrast, detection of p53 was not observed in normal and dysplastic urothelium. p53 positivity was related to the degree of differentiation and to the stage of the disease (Pf = .01 and Pt = .03, respectively). Concerning Ki-67 antigen, its expression was found in 57.5% of TCCs. There was a strong overall correlation of Ki-67 with tumor stage (Pt = .002) and grade (Pf = .002). Univariate statistical analysis showed that the expression of p53 and Ki-67 was significantly correlated to poor prognosis (P = .02, P = .02, respectively). On multivariate analysis, none of these markers but only stage and grade were significantly correlated to prognosis (P = .02, P = .02, respectively). These findings suggest that overexpression of bcl-2 protein may be an early event in tumorigenesis. Tumors with loss of bcl-2 positivity and overexpression of p53 and Ki-67 had an unfavorable prognosis; however, in multivariate analysis, they had no independent prognostic value.     

Hepatocellular proliferation and development of hepatocellular carcinoma: a case-control study in chronic hepatitis C

Patients with hepatitis C have an increased risk of developing hepatocellular carcinoma (HCC). This is related to the stage of chronic liver disease, as characterized histologically by hepatic fibrosis and architectural distortion, but it is unclear whether histological markers can define the risk of developing HCC. We conducted a case-control immunohistochemical study of Ki-67, a marker for hepatocellular proliferation, in livers of 18 patients who had developed HCC more than 2 years after the biopsy specimen had been taken. Using conditional logistic regression analysis, the results were compared with 18 selected controls, who were age-matched patients with hepatitis C of similar histological stage who had not developed HCC. We also examined livers for cellular dysplasia, p53 mutations, and bcl-2 overexpression, and assessed whether the results could be correlated with demographic and disease-related variables, such as gender, region of birth, alcohol consumption, severity of liver disease, HCV genotype, and markers of hepatitis B virus (HBV) infection. Livers from patients who developed HCC were more often positive for Ki-67 (13 of 18 [72%] v 9 of 18 [50%]; P = .06) and tended to have higher mean Ki-67 scores (6 +/- 7.5 v 3 +/- 4.4; P = .10) compared with control cases. In the HCC-predisposed group, three livers showed large cell dysplasia, two were positive for p53 mutations, and two for bcl-2 overexpression. In contrast, in the non-HCC group, only one case had dysplasia, and none were positive for immunostaining for p53 or bcl-2 mutations. With the exception of one case, all livers with large cell dysplasia or p53 mutations and bcl-2 overexpression were also positive for Ki-67. Twelve (55%) of the 22 Ki-67-positive cases were anti-HBc-positive in the serum, in contrast to 2 of 14 (14%) patients in the Ki-67-negative group (P = .01). Patients with evidence of past infection with HBV were more often Ki-67 positive than those who had no evidence of past infection (85% [11 of 13] v 45% [10 of 22]; P = .02). There were no other associations between demographic or disease-related variables and Ki-67 expression. Increased hepatocellular proliferative activity, as assessed by Ki-67 expression, may be one factor indicative of an increased risk of developing HCC among patients with chronic hepatitis C. Furthermore, past infection with HBV appears to be an important correlate of increased hepatocellular proliferation in hepatitis C.     

Spontaneous programmed cell death in infiltrating duct carcinoma: association with p53, BCL-2, hormone receptors and tumor proliferation

Recent evidence has emphasized the importance of programmed cell death or apoptosis in the maintenance of tissue homeostasis and pathogenesis of tumors. This study, analyzed in breast cancer, investigates the significance of apoptosis in relation to the expression of p53 and bcl-2 proteins, tissue proliferation defined by Ki-67 expression, hormone receptors and tumor grade. The extent of apoptosis was defined by morphological criteria and the TUNEL (Tdt-mediated dUTP biotin nick end labelling) assay. Immunocytochemistry was performed for p53, bcl-2, estrogen receptor, progesterone receptor and Ki-67 expression. Mutant p53 protein was detected using a mutant specific ELISA. Immunoreactivity of p53 significantly correlated with the presence of mutant p53 protein detected by ELISA (r = 0.654, p = 0.00001). An inverse correlation was observed between bcl-2 expression and the extent of apoptosis (r = -0.33369, p = 0.01912). The extent of apoptosis directly correlated with p53 protein accumulation (r = 0.485, p = 0.00041), Ki-67 immunoreactivity (r = 0.435, p = 0.001), histopathological grade (r = 0.492, p = 0.0003), tumor size (r = 0.326, p = 0.023) and lymph node status (r = 0.287, p = 0.047). A direct correlation was also observed between p53 expression and Ki-67 immunoreactivity (r = 0.623, p = 0.0002). There was no statistically significant association between estrogen and progesterone receptor status and apoptosis. In addition, the TNM stage of the disease correlated with immunoreactivity of p53 (r = 0.572, p = 0.00012) and Ki-67 (r = 0.3744, p = 0.00818). Bcl-2, by inhibiting apoptosis, may cause a shift in tissue kinetics towards the preservation of genetically aberrant cells, thereby facilitating tumor progression. These results imply that rapidly proliferating tumors appear to have a high "cell turnover state" in which there may be an increased chance of apoptosis amongst the proliferating cells. The ability of apoptosis to also occur in the presence of mutant p53 protein suggests the existence of at least two p53-dependent apoptotic pathways, one requiring activation of specific target genes and the other independent of it.     

Diagnostic value of an antibody enzyme-linked immunosorbent assay using affinity-purified antigen in an area endemic for melioidosis

Oral squamous cell carcinoma develops through a series of precancerous stages manifested at the microscopic level as epithelial dysplasia. Mutation of the p53 tumour suppressor gene is thought to be an important component of oral carcinogenesis. p53 regulates cell proliferation and DNA repair by inhibiting the cell cycle at G1/S; loss of p53 function may therefore lead to aberrant cell kinetics. To date, no studies have examined the relationship between p53 protein and alterations in cell kinetics in oral epithelial dysplasia from a single anatomical site. Serial sections were studied from 40 routinely processed biopsy specimens of epithelial dysplasia from the floor of the mouth. The expression of p53 protein was determined by immunohistochemistry and cell proliferation was studied by immunostaining for the cell cycle-dependent protein Ki-67. The number of positive cells per millimetre of basement membrane was determined using computer image analysis and compared with site-matched normal controls. The mean p53 labelling index (LI) in normal mucosa was low, 3.48 +/- 0.92 [mean +/- 95 per cent confidence interval (CI)], and increased sharply in the transition from mild (42.49 +/- 21.71) to moderate (104.86 +/- 51.39) epithelial dysplasia. The mean p53 LI for severe dysplasia was 119.09 +/- 56.50. Differences were also observed in the distribution of p53-positive cells between grades of dysplasia, with the development of compact p53-positive foci in severe dysplasia. Mean proliferative indices, as determined by Ki-67 expression, were significantly associated with grade of epithelial dysplasia. Furthermore, there was a significant correlation between p53 LI and Ki-67 score (r2 = 0.37, P = 0.01). It is concluded that altered p53 protein expression is probably an early event in oral carcinogenesis in the floor of the mouth and is associated with dysregulation of cell proliferation at this site.     

Paclitaxel-induced modification of the effects of radiation and alterations in the cell cycle in normal and tumor mammalian cells

Biopsy specimens from 12 patients with metastatic melanoma were longitudinally analysed to evaluate changes in proliferation activity and CD4+/CD8+ ratios during the course of the disease. The primary tumours of the patients who subsequently had metastatic disease were also each matched with tumours from two controls whose disease remained localized, and were compared with regard to tumour proliferation. Immunohistochemistry was performed using the avidin-biotin complex (ABC) immunoperoxidase technique, using bcl-2, p53, mdm-2 and Ki-67 as the primary monoclonal antibodies, and the percentage of positively stained melanocytic cells was calculated. Frozen sections were also available from metastatic lesions excised from eight of our patients before treatment initiation and at the time of disease progression. These specimens were prepared for microscopy, and quantitative characterization of CD4+ (OKT 4a) and CD8+ (OKT 8) cells was performed. Compared with the localized melanomas bcl-2 expression was higher in those primary melanomas that later metastasized (P = 0.068, Wilcoxon; P = 0.038, median test). Mdm-2 and Ki-67 expression did not differ in the primary tumours of patients and controls, but a statistically significant trend was observed towards increasing expression with the progression of the disease (two-sided exact P-values: 0.04 and 0.05, respectively). Patients with a low Ki-67 index in their first metastasis had a better prognosis when compared with patients with high indexes (P = 0.008, log-rank). Furthermore, most patients with decreasing CD4+/CD8+ ratios had increasing p53 immunoreactivity. Our findings suggest that Ki-67 and bcl-2 may be useful for predicting the prognosis of melanoma patients. Mdm-2 is a new but promising marker in melanoma and deserves further evaluation.     

Skin cancers at Tertiary Referral Skin Hospital in Singapore

BACKGROUND: Skin cancer is the seventh most common cancer in Singapore. This study was performed to determine the pattern of skin cancers seen in a tertiary referral skin hospital. METHODS: Histologically confirmed skin cancers, seen between 1980 and 1991, were analyzed according to age, sex, race, site, and presence/absence of preexisting skin conditions. RESULTS: Of a total of 520 patients, the commonest skin cancer was basal cell carcinoma (BCC) (36.5%), followed by squamous cell carcinoma (SCC) (24.4%), Bowen's disease (16.7%), and mycosis fungoides (9.0%). Malignant melanomas (2.7%) were rare. The sharp increase (26.2%) in BCC in the recent 3 years was largely contributed by a fivefold increase of non-resident Caucasian patients with BCC. All types of skin cancers were more common in Chinese (78.1%) and less frequent in the more pigmented races (9.4%). The men to women ratio was 1.72:1. The peak age distribution was in the 51-70-year group, with the exception of mycosis fungoides (31-50 years). The commonest site involved in BCC was the head and neck (67.0%) and in Bowen's disease the trunk (33.3%). Squamous cell carcinoma was found on the head and neck and the lower extremities with equal frequency (29.3%) and 46.2% of all SCC on the lower extremities occurred in leprosy patients with chronic trophic ulcers. Of patients with Bowen's disease involving the nonsunexposed parts (trunk and upper extremities), 42.6% had probable arsenic exposure evident either from the history or clinical examination. Malignant melanomas were commonly located on the foot (71.4%). CONCLUSIONS: The commonest skin cancers seen were BCC, SCC, Bowen's disease, and mycosis fungoides. There were differences in the site distribution of SCC, Bowen's disease, and malignant melanomas in our study when compared to studies in Caucasians.     

Gastric cancer with p53 overexpression has high potential for metastasising to lymph nodes

Overexpression of the tumour suppressor gene p53 was investigated immunohistochemically in 96 primary gastric carcinomas and 26 corresponding metastatic perigastric lymph nodes. Abnormalities in p53 expression were found in 52 (54%) of the 96 primary carcinomas. Tumours stained positively for p53 frequently metastasised to lymph nodes (the metastatic rate: 85%) compared to findings in those with negative p53 staining (64%, P < 0.05). Ninety-two percent (24/26) of the malignant cells in the lymph nodes stained positively for p53. When the DNA ploidy pattern of the tumour was determined by flow cytometry, the aneuploid tumours in p53 positive and negative groups accounted for 69% and 45%, respectively (P < 0.05). Proliferative activity of the tumour, as measured by Ki-67 labelling, was significantly higher (30.6 +/- 12.0%) in the p53 positive group than that (25.1 +/- 10.7%) in the p53 negative group (P < 0.05). Thus, gastric cancer with a mutant p53 has high proliferative activity and metastasis to lymph nodes will probably occur.     

Pre-operative radio-chemotherapy enhances apoptotic cell death in oral squamous cell carcinoma

The effect of pre-operative radio-chemotherapy (RCT) has been examined in a total of 15 oral squamous cell carcinomas (SCCs), in terms of apoptosis (cell loss) and proliferation. All the patients received pre-operative radiation at a dosage of 30 or 40 Gy, as well as anticancer agents including tagaful (FT), 5-fluorouracil (5-FU), bleomycin (BLM) and peplomycin (PEP). Surgical specimens were obtained before and after RCT, and serial sections were prepared for immunohistochemistry for p53 oncoprotein and Ki-67 antigen, as well as for terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL). TUNEL indices (TI; percentage of TUNEL-positive cells in the tumor cells) before and after RCT were 1.2+/-1.1 and 4.7+/-2.9 in the nine well-differentiated oral SCCs, and 1.0+/-0.7 and 3.9+/-2.1 in the six poorly differentiated SCCs, respectively. Similarly, Ki-67 indices (KI; percentage of Ki-67 antigen-positive cells in tumor cells) before and after RCT were 31.1+/-14.2 and 15.8+/-11.1 in the former, and 37.1+/-7.8 and 8.7+/- 13.4 in the latter, respectively. Thus, pre-operative RCT enhanced apoptotic cell death and abated proliferative activity significantly (P<0.05), regardless of histological differentiation. Enhancement of apoptosis was more prominent in the group treated with FT or 5-FU than with BLM or PEP. Oral SCC with >20% of nuclear p53-positive tumor cells was noted in six cases. Enhanced TI and abadement of KI did not differ among the p53-positive and -negative tumors.     

Expression of a novel antiapoptosis gene, survivin, correlated with tumor cell apoptosis and p53 accumulation in gastric carcinomas

A novel inhibitor of apoptosis designated survivin has recently been found in many common human cancers but not in normal tissues. A potential distribution of survivin in gastric cancer and its implication for apoptosis inhibition have been investigated. Recombinant survivin expressed in Escherichia coli as a glutathione S-transferase fusion protein was used to raise a novel panel of mouse monoclonal antibodies. In an immunohistochemical analysis of 174 cases of gastric carcinomas (stages I-III), anti-survivin monoclonal antibody 8E2 (IgG1) reacted with 34.5% of cases (60 of 174 cases) with a variable number of tumor cells stained (20-100%). In contrast, no expression of survivin in neighboring normal tissues was observed. When stratified for p53 and bcl-2 expression and apoptotic index, the expression of survivin significantly segregated with p53- and bcl-2-positive cases [56.1 versus 15.2% (P = 0.001) and 69.2 versus 31.6% (P = 0.006), respectively] and with a decreased apoptotic index as compared with that of survivin-negative tumors (0.97 +/- 0.64 versus 0.62 +/- 0.39%, P < 0.001). These data identify a role for survivin in promoting aberrantly increased cell viability in gastric cancer and suggest a potential correlation between accumulated p53 and survivin expression in neoplasia.     

High molecular weight acidic polysaccharides from Malva sylvestris and Alcea rosea

BACKGROUND: Recent studies suggest that apoptosis is important in the cell death induced by treatment that damages deoxyribonucleic acid (DNA). We assessed the correlation between the expression of the apoptosis-related proteins, p53 and bcl-2, and the clinical outcome of patients with nasopharyngeal carcinomas (NPCs) who were treated with both DNA-damaging treatments. We also assessed the level of Ki-67, a marker of cell proliferation, in these tumors. METHODS: We evaluated statistically the relationships among the expression of p53, bcl-2, and Ki-67 and clinicopathologic factors, the sensitivity to radiation, the incidence of distant metastases, and survival. RESULTS: The group that was positive for p53 tended to be resistant to radiotherapy and to have a significantly poorer prognosis (p = .05). CONCLUSIONS: The enhanced expression of p53 may be a prognostic factor in patients with NPCs whose tumor is resistant to therapy that damages DNA.     

Ki-67 labeling indices in non-small cell lung cancer: comparison between image cytometry and flow cytometry

Expression of the proliferation-associated nuclear antigen Ki-67 was studied in 27 human non-small cell lung cancers (NSCLCs). We measured immunohistochemical Ki-67 labeling indices using image cytometry (ICM) and flow cytometry (FCM) and compared the indices determined with the two methods. Ki-67 labeling indices of tumor cells ranged from 2% to 59% with ICM, and from 3% to 56% with FCM, varying from case to case. There was a linear correlation of values between the two methods (r = 0.77, P < 0.05). To examine whether Ki-67 labeling indices represent tumor proliferative activity, we studied the relationship between the Ki-67 labeling index and the S-phase fraction determined by FCM. There was a positive correlation between the Ki-67 labeling index and the S-phase fraction (r = 0.91, P < 0.01). Comparison of Ki-67 labeling indices and clinicopathological parameters showed lower Ki-67 labeling indices in well-differentiated tumors than in moderate and poorly differentiated tumors (P < 0.05). No correlation was observed between Ki-67 labeling indices and p53 expression. It was concluded that the Ki-67 labeling index was in fact measured with both ICM and FCM, and that it represents tumor proliferative activity of NSCLCs.     

Expression of the bcl-2 oncoprotein in meningiomas

The purpose of this study was to assess the expression of the bcl-2 oncoprotein in meningiomas and to compare it with the phenotype, the Ki-67 proliferative index and the sex hormone receptor status of the tumors. The expression of the bcl-2 oncoprotein was studied by Western blotting and immunohistochemistry. A quantitative study of the Ki-67 proliferative index and the expression of estrogen and progesterone receptors was performed. Western blot detected the bcl-2 oncoprotein in nearly all meningiomas. Immunohistochemistry detected the oncogene in only 43.5% of the cases. Expression of bcl-2 was essentially by spindle cells of transitional and fibrous meningiomas expressing neural cell adhesion molecule. There was neither correlation between the expression of bcl-2 and Ki-67 proliferative index of meningiomas nor statistical concordance between the expression of bcl-2 oncoprotein by meningiomas and their sex hormone receptor protein status. Inhibition of apoptosis could be involved in the growth of meningiomas with a mesenchymal differentiation.     

The role of p53, MDM2 and c-erb B-2 oncoproteins, epidermal growth factor receptor and proliferation markers in the prognosis of urinary bladder cancer

The immunohistological expression of p53 and MDM2 oncoproteins was examined in paraffin embedded tissue from 106 patients with transitional cell carcinoma of the urinary bladder and was related to various clinicopathological features, the expression of proliferation associated markers (proliferating cell nuclear antigen - PCNA - and Ki-67), c-erb B-2 oncoprotein and epidermal growth factor receptor (EGFR), as well as to survival. MDM2 immunoreactivity was seen in 38% of our cases, and in 14% was accompanied by p53 positive immunohistochemistry. The rate of p53 positivity was associated with grade, stage and papillary status, whereas MDM2 immunopositivity increased with grade and stage (Ta VS T1), and MDM2 labeling index (LI) with stage. MDM2 expression was related to p53 expression and less strongly to proliferation rate (Ki-67 LI). The simultaneous p53 and MDM2 expression was more frequently observed in higher grade and stage tumours. C-erb B-2, EGFR and proliferation marker expression increased with grade, stage and non-papillary configuration. In univariate analysis high grade, solid growth pattern, advanced T-category, cystectomy, EGFR and Ki-67 expression were linked to shorter overall survival but only Ki-67 LI, along with T-category and type of therapy, had independent prognostic value. C-erb B-2 expression and stage were the two independent predictors of disease-free survival and Ki-67 LI and EGFR LI the independent predictors of post-relapse survival. For patients with superficial tumors PCNA LI emerged as the single independent determinator of survival. p53 and MDM2 expression did not appear to have any significant impact on survival, although the simultaneous expression of p53 and MDM2 turned out to be a highly significant parameter of shortened overall survival in univariate analysis.     

Bcl-2 expression and its association with cell kinetics in human gastric carcinomas and intestinal metaplasia

The bcl-2 protooncogene was initially discovered at the t(14;18) chromosomal breakpoint in follicular lymphomas. It has been demonstrated that bcl-2 protein (Bcl-2) expression blocks apoptosis and plays an important role in cell development and maturation. In the present study, Bcl-2 expression was immunohistochemically examined in 103 cases of gastric carcinoma, as well as 64 cases of non-carcinous gastric mucosa, and its correlation with apoptosis, cell proliferation and p53 immunoreactivity was investigated. Bcl-2 was detected in 18.0% of differentiated-type gastric carcinomas (9 of 50) and 7.5% of the undifferentiated type (4 of 53). In adjacent intestinal metaplastic gastric epithelium, the incidence of Bcl-2 positivity in the incomplete type (21/23, 91.3%) was significantly higher than in the complete type (23/41, 56.1%) (P < 0.04). Double immunostaining for Bcl-2 and Ki-67 clearly revealed the majority of Bcl-2-positive cancer cells to be in a nonproliferating state, although some cancer cells expressed both proteins together. Statistical assessment demonstrated that the average Ki-67 labeling index and apoptotic labeling index in Bcl-2-positive foci were significantly lower than in Bcl-2-negative foci (P < 0.0001, P < 0.0003). In addition, a significant dissociation between Bcl-2 and p53 immunoreactivity was found in cancer tissues. These results indicate that aberrant Bcl-2 expression in gastric carcinomas possibly originates from intestinal metaplastic epithelium, and suggest a possible role in tumor development and growth.     

Different expression of Bcl-2 protein in gastric adenomas and carcinomas

In order to cast light on the possible role of bcl-2 protein (Bcl-2) expression in gastric tumorigenesis, 33 cases of gastric adenomas and carcinomas originating from the same stomachs were immunohistochemically investigated for Bcl-2 protein (Bcl-2) expression, accumulation of p53 protein and cell proliferation as determined by the Ki-67 labeling index (LI). Bcl-2 expression was detected in 24/33 (72.7%) adenomas and in 6/33 (18.2%) carcinomas, the difference being statistically significant (P = 0.0001). Only 4 of 33 (12.1%) cases exhibited expression in both adenoma and carcinoma lesions in the same stomachs. Immunoreactivity was decreased in areas of cellular and structural atypia in adenoma lesions (P < 0.008), and appeared to be positively linked to the tumor progression and the degree of differentation in carcinomas, although it did not reach statistical significance. Accumulation of p53 protein was rare in the adenomas but was found in 15/33 (45.5%) of carcinoma lesions, with a significant dissociation from Bcl-2 immunoreactivity. No apparent relation between Ki-67 LI and either adenoma grading or carcinoma typing was noted, although average Ki-67 LI of the highest labeling areas in carcinomas was statistically higher than in adenomas (P = 0.0001). These results indicate that the regulation of Bcl-2 expression may differ between gastric adenomas and carcinomas, may be correlated with tumor differentiative features. In addition, p53 accumulation may play an important role in the onset of malignancy.     

Cancer conferences. Can they be improved?

In a previous study, we showed that overexpression of cyclin D, a G1 cyclin, is frequently associated with keratinocyte carcinogenesis as an early event. Another G1 cyclin, cyclin E, was recently suggested to be a prognostic marker for breast cancer. In order to evaluate the role of cyclin E in human keratinocyte carcinogenesis, we analysed the expression of cyclin E by immunohistochemistry in normal skin, seborrheic keratosis (SK), keratoacanthoma (KA), actinic keratosis (AK), Bowen's disease (BD), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Positive cells were seen rarely in normal epidermis, in 9 of 20 cases of SK, in 5 of 6 cases of KA, in 9 of 13 cases of AK and in all 27 cases of BD. Some of the cases of AK and BD had positive cells in the superficial epidermis, where atypicality is less obvious. In contrast, positive cells were seen in 4 of 25 cases of SCC and none of 15 cases of BCC. These results suggest that expression of cyclin E plays a role in the formation of benign and premalignant keratinocytic tumors, whereas down-regulation of cyclin E expression may be involved in carcinogenesis in human keratinocytes.