What is the value of bcl-2 protein detection for histopathologists?

Hypertrophic eosinophilic gastroenteropathy is associated with reduced enterocyte apoptosis

AIMS

To investigate the cause of grossly elongated villi in four children presenting with obstruction due to a novel form of eosinophilic gastroenteropathy in which there was profound hyperplasia of the intestinal villi with grossly increased villous/crypt ratio and prominent mucosal eosinophilia. Increased eosinophils were also present in the muscularis propria and submucosa. All had intermittent diarrhoea and signs of a protein-losing enteropathy.

METHODS AND RESULTS

The cause of the grossly elongated villi was investigated by studying enterocyte proliferation (Ki67), survival factors (bcl-2) and apoptosis (TUNEL) in these patients (n = 4) and normal (jejunum n = 6, ileum n = 6) and disease (n = 6) controls. The most remarkable finding was that apoptotic enterocytes were undetectable in the elongated villi.

CONCLUSIONS

It seems likely that a defect in the regulation of apoptosis of the epithelium occurs which could explain the remarkable hyperplasia of the villi seen.

Applications of Flow Cytometry and Immunohistochemistry to Diagnostic Hematopathology

Objective.—Diagnostic hematopathology depends on the applications of flow cytometric immunophenotyping and immunohistochemical immunophenotyping combined with the cytomorphology and histologic features of each case. Select cases may require additional ancillary cytogenetic and molecular studies for diagnosis. The purpose of this review is to focus on the applications of flow cytometric and immunohistochemical immunophenotyping of paraffin-embedded tissue to diagnostic hematopathology. Advantages and disadvantages of these techniques are examined.

Data Sources.—The literature is extensively reviewed (PubMed 1985–2003) with an emphasis on the most recent applications and those that are most useful clinically, both diagnostically and prognostically.

Study Selection.—Studies were selected based on statistically significant results in large studies with reported adequate clinical follow-up.

Data Extraction.—The methodology was reviewed in the selected studies to ensure reliable comparison of reported data.

Data Synthesis.—Flow cytometric immunophenotyping offers the sensitive detection of antigens for which antibodies may not be available for paraffin immunohistochemical immunophenotyping. However, paraffin immunohistochemical immunophenotyping offers preservation of architecture and evaluation of expression of some proteins, which may not be available by flow cytometric immunophenotyping. These techniques should be used as complimentary tools in diagnostic hematopathology.

Conclusions.—There are extensive applications of flow cytometric and immunohistochemical immunophenotyping to diagnostic hematopathology. As cytogenetic and molecular findings evolve in diagnostic hematopathology, there may be additional applications of flow cytometric and immunohistochemical immunophenotyping to this field of pathology.

Endometrial Hyperplasia: A Review

Endometrial hyperplasia is a precursor to the most common gynecologic cancer diagnosed in women: endometrial cancer of endometrioid histology. It is most often diagnosed in postmenopausal women, but women at any age with unopposed estrogen from any source are at an increased risk for developing endometrial hyperplasia. Hyperplasia with cytologic atypia represents the greatest risk for progression to endometrial carcinoma and the presence of concomitant carcinoma in women with endometrial hyperplasia. Abnormal uterine bleeding is the most common presenting symptom of endometrial hyperplasia. Specific Pap smear findings and endometrial thickness per ultrasound could also suggest the diagnosis. Unopposed estrogen in women taking hormone replacement therapy increases the risk of endometrial hyperplasia. Tamoxifen has demonstrated its efficacy in treating women at risk for breast cancer, but it increases the risk of endometrial hyperplasia. The choice of treatment for endometrial hyperplasia is dependent on patient age, the presence of cytologic atypia, the desire for future childbearing, and surgical risk. Endometrial hyperplasia without atypia responds well to progestins. However, women with atypical hyperplasia should be treated with hysterectomy unless other factors preclude surgery.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe the definition and classification of endometrial hyperplasia, to outline the clinical features of a patient with endometrial hyperplasia, to point out the natural history of endometrial hyperplasia, and to summarize the diagnostic options for patients with endometrial hyperplasia.

Clinicopathologic significance of bcl-2 expression in the surgical treatment of oral tongue carcinoma

AIM

There is still controversy on the incidence of positive expression of bcl-2 and its prognostic significance for oral tongue carcinoma patients who are treated by surgery. The present study aims at resolving the controversy on the clinicopathologic significance of bcl-2 in a well selected group of patients who satisfy the recruitment criteria: (1) oral tongue carcinoma, (2) squamous cell carcinoma, (3) primary surgical treatment.

METHOD

Bcl-2 expression was studied by immunohistochemistry on glossectomy specimens of 73 patients. The expression of bcl-2 was correlated with clinicopathologic data.

RESULTS

Of the 73 tumours, 11% had positive expression of bcl-2. Bcl-2 expression was not significantly correlated with tumour grade, stage, nodal metastasis and survival.

CONCLUSION

Bcl-2 expression played a minor role in oral tongue carcinoma. It had no significant correlation with tumour grade, stage and nodal metastasis. It also had no prognostic value on survival for patients who were treated by primary surgery.

Complex pathological diagnosis of granulocytic sarcoma: apropos of a case

The diagnosis of granulocytic sarcoma can be very difficult when there is no demonstrable abnormality in the peripheral blood or bone marrow. We present the diagnostic algorithm of granulocytic sarcoma by reporting on a case mimicking large cell lymphoma without previous manifestation of acute myeloid leukemia or a myeloproliferative disorder. After standard histoprocessing, we used immunohistochemical and molecular biological methods to analyze our case. The lymph node showed diffuse infiltration of immature blast cells resembling large cell lymphoma. However, immunohistochemistry did not support this diagnosis. The tumor cells showed LCA, bcl-2, CD43, CD34 and myeloperoxidase positivity. We also detected bcl-2 gene rearrangement. In case of a lack of a specific histological picture, particularly in poorly differentiated tumors, only some minor histological signs in combination with immunohistochemistry and molecular diagnostic methods can help to render the correct diagnosis.

Proteins encoded by genes involved in chromosomal alterations in lymphoma and leukemia: clinical value of their detection by immunocytochemistry

Acquired chromosomal anomalies (most commonly translocations) in lymphoma and leukemia usually result in either activation of a quiescent gene (by means of immunoglobulin or T-cell-receptor promotors) and expression of an intact protein product, or creation of a fusion gene encoding a chimeric protein. This review summarizes current immunocytochemical studies of these 2 categories of oncogenic protein, with emphasis on the clinical relevance of their detection in diagnostic samples. Among the quiescent genes activated by rearrangement, expression of cyclin D1 (due to rearrangement of the CCND1 [BCL-1] gene) is a near-specific marker of t(11;14) in mantle cell lymphoma; BCL-2 expression distinguishes follicular lymphoma cells from their nonneoplastic counterparts in reactive germinal centers and appears to be an independent prognostic marker in diffuse large cell lymphoma; and TAL-1 (SCL) expression identifies T-cell acute lymphoblastic neoplasms in which this gene is activated. The protein products of other genes activated by chromosomal rearrangement have a role as markers of either lineage (eg, PAX-5 [B-cell-specific activator protein] for B cells, including B-lymphoblastic neoplasms), or maturation stage (eg, BCL-6 for germinal-center and activated B cells and MUM-1/IRF4 for plasma cells). Currently, no hybrid protein encoded by fusion genes is reliably detectable by antibodies recognizing unique junctional epitopes (ie, epitopes absent from the wild-type constituent proteins). Nevertheless, staining for promyelocytic leukemia (PML) protein will detect acute PML with t(15;17) because the microspeckled nuclear labeling pattern for PML-RARalpha is highly distinctive. Similarly, antibodies to the anaplastic lymphoma kinase (ALK) tyrosine kinase are valuable (because wild-type ALK is not found in normal lymphoid tissue) in detecting neoplasms (CD30-positive large T-cell lymphomas) with t(2;5) or its variants. Thus, immunocytochemical detection of the products of many rearranged genes in lymphoma and leukemia can be clinically informative and provide information on cellular and subcellular protein expression that cannot be inferred from studies based on messenger RNA.

Estrogen and Bcl-2: gene induction and effect of transgene in experimental stroke

Female rodents producing endogenous estrogens are protected from stroke damage in comparison with male counterparts. This natural protection is lost after ovariectomy or reproductive senescence. The aim of this study is to determine whether estrogen reduces early neuronal injury and cell loss after ischemia by increasing the expression of Bcl-2. Male, intact female, ovariectomized, and estrogen-repleted ovariectomized rats were subjected to middle cerebral artery occlusion, and 22 hr later the level and localization of Bcl-2 mRNA and protein were determined. The levels of post-ischemic bcl-2 mRNA and protein were increased exclusively in neurons within the peri-infarct region. Intact females and estrogen-treated castrates demonstrated increased bcl-2 mRNA and protein expression compared with males and estrogen-deficient females, accompanied by a decrease in infarct size. To test the hypothesis that the neuroprotective mechanism of estrogen functions via Bcl-2, we compared ischemic outcome in male, female, and ovariectomized wild-type mice and mice overexpressing Bcl-2 exclusively in neurons. Wild-type female mice sustained smaller infarcts compared with males. Bcl-2 overexpression reduced infarct size in males, but provided no added protection in the female. Moreover, ovariectomy exacerbated infarction in wild-type females, but had no effect in Bcl-2 overexpressors. These data indicate that overexpression of Bcl-2 simulates the protection against ischemic injury conferred by endogenous female sex steroids. We concluded that estrogen rescues neurons after focal cerebral ischemia by increasing the level of Bcl-2 in peri-infarct regions and that estrogen-induced bcl-2 gene expression is an important downstream component of neuronal protection in female stroke.

The clinicopathological significance of bcl-2 expression in the surgical treatment of laryngeal carcinoma

Bcl-2 expression was studied by immunohistochemistry on laryngectomy specimens from 176 patients. Of the 176 tumours, 11% had positive bcl-2 staining. Bcl-2 expression was significantly correlated with tumour grade: 5% of well-differentiated tumours, 12% of moderately-differentiated tumours and 23% of poorly-differentiated tumours had positive expression of bcl-2. Nodal metastases were also found to be significantly related to bcl-2 expression: 36% of nodal metastases for negative bcl-2 expression compared with 70% for positive expression. The risk of nodal metastases increased significantly with the presence of bcl-2 expression, moderate or poor differentiation and supraglottic involvement. The risk of nodal metastases increased significantly with the presence of increasing numbers of risk factors: 11% without risk factor, 21% with one risk factor, 49% with two risk factors and 77% with three risk factors. Bcl-2 expression in laryngeal carcinoma is significantly correlated with tumour grade and nodal metastases. It has added prognostic value for nodal metastases together with tumour grade and site of tumour involvement.

Prognostic significance of Bcl-2 and p53 expression in advanced laryngeal squamous cell carcinoma

BACKGROUND

Proteins regulating the cell cycle and cell death are frequently abnormally expressed in cancer. Several of these, particularly p53 and Bcl-2, have been widely suggested as possible prognostic markers in diverse human malignancies. Their role in predicting outcome in squamous cell carcinomas of the head and neck is unclear and may depend on the location, stage, and treatment of the tumor.

METHODS

To assess this question specifically for advanced squamous cell carcinoma of the larynx, we studied 69 patients with stage III or IV tumors, all but 6 of whom were treated with surgery plus postoperative irradiation by a single physician. We studied the patients retrospectively to test the association between expression of Bcl-2 and p53, as assessed by immunohistochemistry, with treatment outcome and survival.

RESULTS

Twenty of the 69 patients died from their tumor (poor outcome); the rest were alive and tumor free at the last follow-up or died of unrelated causes without clinical tumor recurrence (good outcome). Fourteen tumors had detectable Bcl-2 expression, including 8 scored as overexpressors. Thirty-nine tumors overexpressed p53. Expression of neither Bcl-2 nor p53 was associated with outcome, overall survival, or disease-free survival. Only tumor stage was significantly associated with outcome and disease-free survival.

CONCLUSION

These data indicate that assessing expression of p53 or Bcl-2 is unlikely to be prognostically useful for surgically treated advanced laryngeal carcinoma.

Interrelationship between Epstein-Barr virus infection in gastric carcinomas and the expression of apoptosis-associated proteins

AIMS

Epstein-Barr virus (EBV) and its associated proteins may be protective against the occurrence of apoptosis that would normally inhibit cancer development and progression. Alternatively, the viral infection may cause altered or mutated expression of oncogenes or tumour suppressor genes that are necessary for tumour development, an action that may also involve apoptosis. In this study, a relationship was sought between occurrence of EBV infection, expression of apoptosis-associated proteins (tumour suppressor gene p53 and oncogenes c-myc and bcl-2) and levels of cell death (apoptosis or necrosis) in 119 cases of gastric carcinoma.

METHODS AND RESULTS

The EBV status of the gastric carcinomas (using the EBV-encoded small RNA I (EBER-1) and in-situ hybridization), stage and grade of tumour and sex of patients were compared for bcl-2, p53 and c-myc expression patterns. EBER-1 was detected in approximately 20% of cases studied. There was no significant correlation between levels of cell death in the tumour tissue and EBV status. In the protein analyses, development and progression of gastric carcinoma, with or without EBV infection, was independent of bcl-2 expression. However, in gastric cancers with EBV infection, p53 overexpression was inhibited and c-myc expression was increased in early stage cancers, in comparison with decreased c-myc expression in late stage cancers.

CONCLUSIONS

The p53 and c-myc expression patterns indicate that EBV-infected gastric carcinomas are less likely to have a natural regression via apoptosis at an early stage and explain, in part, the resistance to treatment of late stage of gastric cancers.

Quantitative fluorescence cytometric analysis of Bcl-2 levels in tumor cells exhibiting a wide range of inherent Bcl-2 protein expression: correlation with Western blot analysis

BACKGROUND

A protocol to measure a wide range of Bcl-2 protein expression using quantitative fluorescence cytometry (QFCM) in different cell types was developed for use with flow cytometry. Bcl-2 measurements obtained by flow cytometry were correlated with Western blot Bcl-2 measurements to confirm specificity of the Bcl-2-FITC staining. This protocol was applied to measure absolute levels of Bcl-2 protein in different tumor cell lines including Bcl-2-transfected breast carcinoma cell lines and in peripheral blood lymphocytes (PBL).

METHODS

HL-60, K562, DOHH2, Jurkat, MDA435/LCC6, MCF7 cell lines, and PBL derived from normal donors were fixed, permeabilized, stained with anti-Bcl-2-FITC antibody and evaluated by QFCM. In parallel, the same cells were evaluated for Bcl-2 protein expression by Western blot analysis. Mitochondrial localization of anti-Bcl-2-FITC antibody inside cells was confirmed using fluorescence imaging microscopy.

RESULTS

Bcl-2 expression in different cell types could be accurately quantified based on antibody-binding capacity (ABC) ranging from 12.6 x 10(3) antibody-binding sites in HL-60 cells to 1.64 x 10(6) antibody-binding sites in a Bcl-2-transfected MDA435/LCC6 clone. The data from flow cytometry analysis correlated well with Western analysis (R(2) = 0.78). Bcl-2-FITC staining colocalized with dyes specific for mitochondria.

CONCLUSIONS

The Bcl-2 staining protocol described here was shown to be specific, sensitive, and it was able to provide higher resolution as well as more reproducible quantitation of Bcl-2 protein content in cells when compared with Western blot methods. Quantitation of Bcl-2 content in cells by QFCM may be useful for monitoring Bcl-2 expression in cells undergoing various treatments in vitro and in vivo.

Low-grade B-cell lymphoma and concomitant extensive sarcoidlike granulomas: a case report and review of the literature

Sarcoidlike granulomas may occur in association with Hodgkin lymphoma and non-Hodgkin lymphoma. The granulomas may be concomitant and so extensive that they obscure the malignant process. In addition, a sarcoidosis-lymphoma syndrome has been described in which there appears to be a relationship between sarcoidosis and the development of a lymphoproliferative disorder. We report a case of a low-grade B-cell lymphoma with concomitant extensive sarcoidlike granulomas. The patient had no diagnostic clinical evidence of sarcoidosis, although she had an elevated serum calcium level and increased serum angiotensin converting enzyme activity. Increased serum calcium and serum angiotensin-converting enzyme activity have been associated with clinical sarcoidosis but have also occasionally been described in association with Hodgkin lymphoma and non-Hodgkin lymphoma without evidence of sarcoidosis. We describe our findings and illustrate the usefulness of immunoperoxidase immunophenotyping techniques in such a case.

Detection of the T(14;18) translocation in follicle centre cell lymphomas in South African ethnic groups using PCR

PCR was used to detect the t(14;18) translocation in 64 South African cases with follicle centre cell lymphoma. DNA was purified from paraffin-embedded tissue collected from different ethnic groups namely white, black and "mixed" race patients, and primers used to detect both mbr and mcr. The overall incidence of the translocation was 45%, which is similar to that of Caucasian and Chinese patients. The ratio of rearrangements occurring at the mbr and mcr was 7:1 which may be an overestimation. The ratio was three times higher for the "mixed" race group compared to whites, and this suggests that there may be ethnic variation in breakpoints in South African patients.

p53 but not bcl-2 is expressed by most cholangiocarcinomas: a study of 28 cases

AIMS

To examine the frequency and pattern of expression of p53 and bcl-2 in archival material from patients with cholangiocarcinomas and to evaluate their respective roles in its pathogenesis, diagnosis and prognosis.

METHODS AND RESULTS

Twenty-eight surgical cases of cholangiocarcinomas diagnosed at St James's University Hospital and 16 control cases were immunostained with monoclonal antibodies to p53 and bcl-2 using streptavidin-biotin complex method. Pressure cooker was used for antigen retrieval. Of the cholangiocarcinomas, 85.7% (24/28) overexpressed p53. The intensity of staining in these cases varied from 1+ in 2, 2+ in 10 and 3+ in 12 cases. None of the 28 tumours expressed bcl-2. The well differentiated nature of the tumour made assessment of dysplasia difficult, however, where present it did not express p53 or bcl-2. The bile duct epithelium adjacent to the tumour and in the control cases did not show any significant nuclear staining for either antigen.

CONCLUSIONS

Overexpression of p53 appears to play an important role as a late event in the pathogenesis of cholangiocarcinomas, while we found no evidence of bcl-2 overexpression. The expression of p53 in 86% of the invasive tumours, as compared to its lack in the adjacent normal bile duct epithelium, makes it potentially useful in the diagnostic histopathology of these cases.

Loss of bcl-2 expression in ductal carcinoma in situ of the breast relates to poor histological differentiation and to expression of p53 and c-erbB-2 proteins

AIM

This study (1) investigates the incidence of bcl-2 protein expression in a series of 108 cases of ductal carcinoma in situ (DCIS), including 25 with early invasive carcinoma, and (2) evaluates the relationship of bcl-2 expression to the histological grade of DCIS and to the expression of oestrogen receptor (ER), c-erbB-2 and p53 proteins.

METHODS AND RESULTS

The expression of bcl-2, oestrogen receptor (ER), c-erbB-2 and p53 proteins was determined immunohistochemically. Cases were regarded as positive for individual antibodies when at least 10% of the DCIS cells showed positive staining. DCIS was graded histologically as well (n = 9), intermediately (n = 24), or poorly differentiated (n = 75). bcl-2 expression was documented in 57 cases (53%) and was strongly associated with the histological grade of DCIS (P < 0.0001). All cases of well-differentiated DCIS were bcl-2 positive and loss of bcl-2 expression was almost exclusively confined to poorly differentiated DCIS lesions. bcl-2 expression was also closely associated with positive ER status (P < 0.0001). Forty-seven of 57 (82%) bcl-2 positive cases were ER positive while 49/51 (96%) bcl-2 negative cases were ER negative. There was a significant inverse correlation between bcl-2 expression and both p53 protein expression (P = 0.0004) and c-erbB-2 expression (P < 0.0001). Nineteen of 24 (79%) p53 positive cases and 38/45 (84%) c-erbB-2 positive cases showed loss of bcl-2.

CONCLUSIONS

Loss of bcl-2 expression occurs in poorly differentiated DCIS and is related to negative ER status and to positive p53 and c-erbB-2 status. This pattern of bcl-2 expression and its association with other biological markers in DCIS is similar to that reported in invasive breast carcinoma.

Apoptosis-associated proteins in oral lymphomas from HIV-positive patients

Extranodal oral lymphomas, seen with increasing frequency in HIV infection, may have dysfunctional apoptotic mechanisms that favor tumor progression. The purpose of this study was to evaluate extranodal lymphomas from HIV-positive patients for expression of apoptosis-associated proteins. Correlations were made with 10 histologically comparable extranodal lymphomas from HIV-negative patients and 6 hyperplastic lymph nodes from otherwise healthy young adults. Formalin-fixed tissue sections were immunohistochemically stained for apoptosis-associated proteins (Bcl-2, Bcl-x, Bax, Bak, p53, MDM2, BHRF). In situ hybridization was also done on deparaffinized sections for Epstein-Barr virus EBER mRNA. Eighteen consecutive oral lymphomas were studied in HIV/AIDS-positive patients. Four of 5 intermediate-grade lymphomas expressed Bcl-2 to a greater degree than did high-grade lymphomas (4 of 13). Most lymphomas were positive for Bcl-x and Bax, and few expressed Bak. The staining patterns for these proteins were similar to those seen in HIV-negative patients. Staining patterns were relatively consistent in the hyperplastic lymph nodes, whereas such patterns were irregular in lymphomas. Positive p53 staining was seen in 11 of 18 HIV-positive cases; 9 of these were also MDM2-positive. Double stains suggested that both p53 and MDM2 proteins were expressed in the same cells in these nine cases. Epstein-Barr virus-EBER mRNA was detected in 14 of 18 cases and in 3 of 10 cases from HIV-negative patients. BHRF staining was evident in only a few cells of three HIV-positive lymphomas. The irregular expression of Bcl-2, Bcl-x, Bax, and Bak in oral lymphomas indicates dysfunctional apoptotic mechanisms in these tumors. Bcl-2 staining differs with tumor grade. Positive staining for p53 and MDM2 proteins is a notable feature of lymphomas in HIV-positive patients and may relate to binding of MDM2 to wild-type p53. Epstein-Barr virus is more commonly associated with oral lymphomas in HIV-positive patients, although the Epstein-Barr virus-produced protein BHRF, which has Bcl-2-like activity, is minimally expressed.

The extent of proliferative and apoptotic activity in intraductal and invasive ductal breast carcinomas detected by Ki-67 labeling and terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP nick end labeling

BACKGROUND

The balance among cell proliferation, cell differentiation, and cell death determines the cell number in a population as well as the size or even the stage of a tumor. Thus, to improve our understanding of the pathogenesis of neoplasms, it is important to investigate the regulation of both cell proliferation and cell death.

METHODS

This study examined the occurrence of apoptosis and proliferative capacity in 46 breast carcinomas: 20 intraductal carcinomas (ductal carcinomas in situ [DCIS]) and 26 infiltrative ductal carcinomas (IDC). Terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP nick end labeling (TUNEL) and immunostaining with the Ki-67 antibody were used in the examination. A ladder of DNA fragments induced by apoptosis was demonstrated by means of DNA agarose gel electrophoresis in 10 of the available TUNEL positive and negative samples.

RESULTS

The results were correlated with p53, bcl-2, estrogen receptor (ER), and progesterone receptor (PR) protein expression, which would suggest association with apoptosis by immunohistochemistry. The apoptosis and proliferation of each cancer were expressed as the number of tumor cells undergoing apoptosis and proliferation per 1000 tumor cells. The extent of apoptosis was more frequently observed in DCIS than in IDC (21.9+/-6.8 vs. 4.0+/-0.9, P < 0.001), and the proliferation activity was significantly higher in IDC than in DCIS (16.8+/-6.5 vs. 3.5+/-0.8, P < 0.006). Apoptosis associated with MIB-1 positive cells and TUNEL labeling was significantly higher in IDC than in DCIS (3.26 vs. 0.42, P=0.001). In DCIS, apoptosis was correlated with p53 (r=0.663, P=0.005), and p53 had a reverse correlation with bcl-2 (r=0.620, P= 0.018). Moreover, bcl-2 expression was associated with ER (P=0.028) and PR (P= 0.005) expression in both DCIS and IDC.

CONCLUSIONS

The results of this study show that a higher degree of apoptosis and lower proliferation activity in intraductal carcinoma result in a steady-state, self-renewing condition in which net growth of the tumor is rare. The results also indicate that apoptosis was altered by the expression of p53, bcl-2, ER, and PR.

Human herpes virus 8 (HHV-8) in Kaposi's sarcoma: lack of association with Bcl-2 and p53 protein expression

AIMS

Human herpes virus 8 (HHV-8) is the infectious agent implicated in the pathogenesis of Kaposi's sarcoma, although its mode of action is unclear. Recent work indicates that the HHV-8 genome encodes a viral Bcl-2 homologue (v-Bcl-2). The aim of this study was to explore Bcl-2 expression in Kaposi's sarcoma using a unique set of HHV-8 positive and negative cases, and to determine whether there is a relation with p53 expression.

METHODS

Up to 18 specimens from 17 patients were selected. HHV-8 status was determined using nested polymerase chain reaction (PCR) to the open reading frame (ORF) 26, with further confirmation by TaqMan PCR. In addition, Bcl-2 and p53 immunohistochemistry were performed using standard protocols.

RESULTS

The results suggest that Bcl-2 and p53 expression is independent of HHV-8 status. In addition, there does not appear to be a direct correlation with disease stage.

CONCLUSIONS

HHV8 histopathogenesis is likely to be a multifactorial complex process, which may be mediated in part by viral genes and apoptosis regulating homologues.

Bcl-2 expression and prognosis of patients with endometrial carcinoma

Bcl-2 protein inhibits apoptosis, reduces the requirement for growth factors, and thereby extends the survival of cells. Recent findings of Bcl-2 in several solid tumors suggest that it might contribute to the genesis of some types of cancer. Over-expression of Bcl-2 might play a role in carcinogenesis and malignant progression of endometrial carcinoma. The aims of this study were to determine Bcl-2 expression in endometrial carcinoma in relation to other histopathologic prognostic factors, and to test its prognostic significance in patients with endometrial carcinoma. A total of 61 endometrioid-type endometrial carcinomas were immunohistochemically investigated for Bcl-2 expression on cryostat sections. Bcl-2 localization was observed in cytoplasm in 18 tumors, in nucleus in 27 tumors, or in both in 5 tumors. In 11 tumors, Bcl-2 was observed neither in cytoplasm nor in nucleus. There was not a statistically significant relationship between grade of tumor and Bcl-2 expression. Cytoplasmic Bcl-2 became less frequently expressed as the tumor invaded the myometrium deeper (p < 0.025). Retroperitoneal lymph-node dissection was performed in 57 patients. Multiple-regression analysis showed that lymph-vascular space invasion and nuclear expression of Bcl-2 were correlated to pelvic lymph-node metastasis (p < 0.0001 and < 0.05 respectively). Univariate Cox regression analysis revealed that nuclear Bcl-2 expression was associated with shorter survival (p < 0.05) than that of patients with cytoplasmic Bcl-2 expression. Pelvic node metastasis was a significant prognostic factor for patients who underwent systematic retroperitoneal lymph-node dissection. Cox multivariate-regression analysis revealed that pelvic node metastasis and cervical invasion were the most important prognostic factors in this series of patients. When the analysis was made after exclusion of pelvic node metastasis, histologic grade (hazard ratio = 2.4), cervical invasion (hazard ratio = 3.7) and nuclear Bcl-2 expression (hazard ratio = 11.5) were shown to be significant predictors of survival of the patients. These results indicate that aberrant Bcl-2 expression might be involved in malignant progression of endometrioid-type endometrial carcinoma. Site of Bcl-2 localization may be an important predictor of prognosis for patients with endometrioid-type endometrial carcinoma.

Expression of bcl-2 in fetal thymus, thymomas and thymic carcinomas. Association with p53 expression and review of the literature

Bcl-2 is a proto-oncogene inhibiting apoptosis, and p53 is a tumor supressor gene which induces apoptosis. Both seem to take part in tumorigenesis. An inverse relationship between the two genes has been reported in some neoplasms, although the exact mechanism is not fully understood. We have analyzed the expression of bcl-2 and p53 in 18 fetal thymuses and 18 clinically benign and malignant thymomas: bcl-2 was expressed by most medullary lymphocytes and epithelial cells of the normal thymus; p53 was not expressed at all. Bcl-2 and p53 were co-expressed in the majority of the thymomas and the staining reaction was stronger in the clinically malignant ones. It is concluded that although co-expression of bcl-2 and p53 is of doubtful prognostic relevance, the staining pattern of bcl-2 supports the histogenetic classification system of Müller-Hermelink.

Frequent expression of bcl-2 protein in solitary fibrous tumors

The distinction of solitary fibrous tumors from histologically similar neoplasms is often difficult because they rarely occur at a variety of extrapleural sites. CD34 immunoreactivity has recently been recognized to be an adjunct for the diagnosis of solitary fibrous tumors. However, it is now known that CD34 staining is not entirely specific for this entity. We evaluated 23 solitary fibrous tumors and 54 other spindle cell tumors often considered in the differential diagnosis for immunoreactivity using monoclonal antibodies directed against bcl-2 protein, which protects cells from apoptosis and CD34. The patients with solitary fibrous tumors comprised 11 men and 12 women, ranging in age from 35 to 85 years (mean, 57.6 years). Fourteen tumors arose in the pleura, four in the retroperitoneum, three in the superficial soft tissue and one each in the mediastinum and uterine cervix. Nineteen of 23 solitary fibrous tumors (83%), irrespective of tumor site, demonstrated diffuse cytoplasmic staining for bcl-2 protein. bcl-2 immunoreactivity was also observed in five of seven neurofibromas (71%), eight of 10 synovial sarcomas (80%) and one of three spindle cell lipomas (33%). CD34 immunoreactivity was present in all but one solitary fibrous tumor (96%), seven of seven neurofibromas (100%), three of three spindle cell lipomas (100%), five of five dermatofibrosarcomas (100%), three of three hemangiopericytomas (100%) and two of seven malignant fibrous histiocytomas (29%). To date, most of the pleural and extrapleural cases have not shown aggressive features. We suggest that bcl-2 protein can be used together with CD34 in the diagnosis of solitary fibrous tumor to distinguish this entity from other spindle cell neoplasms.

Cell proliferation, bcl-2, c-myc, p53 and apoptosis as indicators of different aggressiveness in small lymphocytic lymphoma (SLL)

Cell proliferation activity, by MIB1 mAb, expression of bcl-2, c-myc and p53 gene proteins and apoptotic index (AI) were assessed in 54 cases of SLL and compared to the morphological subtypes of this disorder, defined by Lennert on the basis of amount and distribution of small and larger activated lymphocytes as diffuse, tumor-forming and pseudofollicular subtypes (DS, TFS, PFS). MIB1 scores showed significant differences between DS, PFS and TFS (5.5%, 16.61% and 24.14%, respectively; p < 0.0001). Worth noting, the MIB1 score did not differ significantly when comparing DS with the diffuse areas of PFS, or TFS with the pseudofollicles of PFS. The mean bcl-2 gene protein score was displayed to a high extent in all subtypes, but less extensively by larger activated lymphocytes that, conversely, expressed c-myc. MIB1 score correlated negatively with bcl-2 and positively with c-myc protein scores. These findings suggest that lymphocytes protected from apoptosis by bcl-2 would be exponed to cell activation and growth acceleration provided by c-myc. This condition would account for a different aggressiveness of morphologically activated subtypes, such as TFS and PFS with larger pseudofollicles. The survival analysis, performed in 23 cases, showed a trend of association of cell proliferation and c-myc expression with a more aggressive progression of the disease. Overexpression of p53 and apoptosis were found only in a minority of cases, unrelated to the subtypes. In conclusion, cell growth fraction, bcl-2 and c-myc assessment may be of help in predicting the aggressiveness of different subtypes of SLL. This approach should be most conveniently applied to PFS, which represents a continuum between DS and TFS, in order to distinguish, in this heterogeneous subtype, more indolent from more aggressive disorders.

Absence of prognostic significance of bcl-2 immunopositivity in non-small cell lung cancer: analysis of 427 cases

The bcl-2 gene product inhibits apoptosis and is thought to participate in oncogenesis. Association of bcl-2 immunopositivity with improved prognosis of non-small cell lung cancers (NSCLC) is controversial. Although two studies have reported better survival in bcl-2-immunopositive NSCLCs, a third series has contradicted this finding. The authors studied a relatively larger case series involving 427 patients for whom detailed information on long-term follow-up was available to determine the prognostic significance of bcl-2 expression. The study included 252 adenocarcinomas (AC), 111 squamous cell carcinomas (SCC), and 64 large cell carcinomas (LC). After antigen retrieval, sections were immunostained using a monoclonal anti-bcl-2 antibody (1:60, Clone 124, Dako) and the avidin-biotin complex technique. Staining was scored as positive or negative and also on a semiquantitative scale as 0, low (<10%), moderate (10% to 75%), or extensive (>75%). Bcl-2 immunoreactivity was correlated with survival using the actuarial survival method, Kaplan-Meier method, and log-rank test and was not associated with statistically significant differences in survival for NSCLCs (P = .5537). Differences in survival remained insignificant even after NSCLCs were stratified for cell type, stage, or grade, singly or in combination. Therefore, using this method, bcl-2 immunopositivity does not appear to act as an independent prognostic indicator in NSCLCs.

Differential expression of apoptosis, Bcl-x and c-Myc in normal and malignant lymphoid tissues

Bcl-x and c-Myc have an important role for the immune response by regulating the programmed cell death (apoptosis) of lymphocytes. Dysfunction of these selection processes can lead to the development of malignant lymphoma. The present study aimed at defining the differential expression of apoptosis, Bcl-x and c-Myc in normal and in malignant lymphoid tissues. Follicular centre lymphoma (FCL-F) and mantle cell lymphoma (MCL) contained the lowest apoptotic indices (AIs), whereas Burkitt's lymphoma (BL) had the highest AIs. The AIs correlated significantly with the growth rates of the tumours and with the extent of Bcl-x expression. Bcl-x was expressed in almost all BL cells, but in few tumour cells in FCL-F and in MCL. c-Myc, in contrast, was found in the majority of the tumour cells in FCL-F and in MCL, but not in BL. Whereas the extent of Bcl-x expression correlated positively with the growth rates, an inverse correlation was observed between the percentages of c-Myc-positive tumour cells and the growth rates of the tumours. We conclude that normal and malignant lymphoid tissues have a distinct pattern of apoptosis and that expression of Bcl-x and c-Myc in B cell lymphoma is differentially regulated.

Apoptosis bcl-2 and p53 expression and their relation to tumour stage in non-small cell lung carcinomas (NSCLC)

Little quantitative data exist on the extent of apoptosis (genetically mediated cell deletion) and no data are available on its relation to p53 and bcl-2 expression and on its value as a prognostic factor in NSCLCs. We examined 38 NSCLCs (26 squamous, 8 adeno, 2 adenosquamous and 2 large cell carcinomas) for the frequency of apoptotic bodies by morphometric methods using haematoxylin eosin stained sections and for the bcl-2 and mutant p53 gene product expression using immunohistochemical techniques. We also evaluated the relation of apoptosis, bcl-2 and p53 expression to tumour stage and to each other. Eleven cases were in stage I, 5 were in stage II, 13 were in stage III and 9 were in stage IV. The mean apoptotic count was 9.52 (r: 2-26); 36.8% of cases were positive for bcl-2 and 76.3% of cases were positive for p53 expression. Statistical analysis did not show any correlation between tumour stage and any of the three tested parameters. There was no statistically significant relation between apoptosis and either p53 or bcl-2 expression. There are conflicting reports on the complex relationship between bcl-2, p53 and apoptosis. bcl-2 is suggested to have a prognostic value, independent from stage in SCLCs. Though we did not find any relation between stage and bcl-2 or apoptosis, it remains to be tested whether they have any independent prognostic value in larger series with survival data.

Prognostic significance of Bcl-2 expression in localized squamous cell carcinoma of the head and neck

This study was conducted to determine whether Bcl-2 overexpression in localized squamous cell carcinoma of the head and neck (SCCHN) might serve as a marker for tumors unlikely to respond to standard treatment. Tissue samples from 33 patients undergoing surgery or irradiation for early-stage SCCHN during the year 1977 to 1992 were stained for Bcl-2. All patients had either T1N0 lesions of the oral cavity, pharynx, or larynx or T1N0 or T2N0 lesions of the true vocal cords. Of the 33 patients, 26 remained disease-free after at least 3 years of follow-up; the remaining 7 patients developed either tumor recurrence or a second primary tumor, 4 of which were fatal. Twelve patients had tissue specimens staining positive for Bcl-2; 6 of these patients had a poor outcome, and 6 had a good outcome. The relationship between poor outcome and overexpression of Bcl-2 in tumor cells was statistically significant (p = .0047 by Fisher's exact test). For tumors overexpressing Bcl-2, there was no significant difference in recurrence rate between those undergoing surgery and those undergoing radiotherapy as the primary mode of treatment. The overexpression of Bcl-2 in early lesions in this study predicted a cure rate of 50%, as opposed to the generally expected 90%, suggesting that Bcl-2 is a significant prognostic indicator in early SCCHN. Future studies will determine if altering the treatment will improve outcome in these patients.

Apoptosis and proliferative activity of non-Hodgkin's lymphomas: comparison with expression of bcl-2, p53 and c-myc proteins

In order to clarify the role of spontaneous apoptosis of non-Hodgkin's lymphomas in the growth regulation system, apoptotic indices (AI) assessed by DNA nick end-labeling and proliferative activity, estimated in terms of KI-67 labeling indices (KI) and mitotic indices (MI), were compared. In addition, expression of bcl-2, p53 and c-myc was also examined in relation to these indicators. For this study, 103 lymphoma cases were used, comprising 72 of B cell and 31 of T cell origin (42 nodal and 62 extranodal). AI, KI and MI were significantly increased in line with bcl-2 negativity and p53 positivity, and there was no relation to the T, B cell classification or expression of c-myc. These indicators positively correlated overall. Positive correlation was stricter in groups believed to represent a good prognostic predictive factor, such as B cell origin, bcl-2(+), p53(-) and c-myc(-). Significant cross-correlation was noted only between bcl-2 versus T, B cell classification. However, no inverse correlation between bcl-2 and p53 was evident. These results suggest, in non-Hodgkin's lymphomas, that apoptosis plays an important role together with proliferative activity in counter-balancing tumor volume, and is strictly linked to bcl-2 expression, less so to p53 expression, but independent of T, B cell classification and c-myc expression. Apoptotic indices may be a predictive indicator for prognosis similar to proliferative activity.

Prognostic markers for colorectal cancer: expression of P53 and BCL2

P53 is a tumor suppressor gene that has been implicated in the pathogenesis of a wide range of tumor types including colorectal cancers. bcl2 is a proto-oncogene that inhibits apoptosis. Immunostaining for P53 and BLC2 protein product was performed in a retrospective series of 80 colorectal carcinomas with a minimum follow-up of 5 years. The aim of the study was to evaluate the prognostic significance of P53 and BCL2 protein expression and their correlation with clinicopathologic variables such as pathologic disease stage (Dukes system), histologic grade, and vascular invasion. The patients were 41 to 76 years of age, and the follow-up ranged between 5 and 10 years. Among the 80 cases, 30 were Dukes stage A and 50 stage B. We found vascular invasion in 21.2%. P53 and BCL2 expression was detected, respectively, in 30.0% and 8.8%. We concluded that the P53 and BCL2 expression detected by immunohistochemistry in routinely processed, paraffin-embedded tissues: (1) has no prognostic significance; and (2) was not correlated with pathologic disease stage, histologic grade, or vascular invasion. Nevertheless, the number of patients in our study was small, and we believe that investigation of a larger series of patients is indicated.

Immunohistochemical localization of Bcl-2 and Bax proteins in in situ and invasive duct breast carcinomas

Bcl-2 and Bax proteins are coded by a family of genes that take part in the manteinance of the balance between cell proliferation rate and programmed cell death in multicellular organisms. The Bax gene acts as promoter of cell death by opposing the death protector effect of the Bcl-2 gene. Expression of the Bcl-2 and Bax proteins has been investigated in 58 cases of duct carcinoma in situ (DCIS) and duct invasive and invasive lobular carcinomas (IC) of the breast. While both proteins were expressed at the same time in normal and benign epithelium, different staining patterns were observed according to the degree of differentiation of the neoplastic epithelium. In well-differentiated DCIS and grade I IC there was a predominance of Bcl-2 protein staining. Grade II lesions co-expressed both proteins. Poorly differentiated DCIS displayed a predominantly Bax protein staining pattern. Therefore, it appears that Bax protein expression, especially in DCIS, relates to more aggressive neoplasms while Bcl-2 protein expression is associated with less aggressive malignant lesions.

Bcl-x gene expression in Hodgkin's disease

Bcl-x is a Bcl-2-family protein that has been previously detected in cortical thymocytes, plasma cells, and activated lymphocytes. We report here on the high detection rate of the Bcl-x protein found in 86% of Hodgkin's disease samples and on the significance regarding its complex role among the Bcl-2-family of proteins: Bcl-x is known to heterodimerize with Bcl-2 (an anti-apoptosis protein) and with Bax, a potent inducer of cell death. Moreover, recent evidences show that Bcl-x may induce multiple drug resistance in vitro, suggesting that chemical or biological interactions with this protein may have potential therapeutic value in Hodgkin's disease.

Bcl-2 expression in malignant melanoma and its prognostic significance

Programmed cell death (apoptosis) is now recognized as an important factor in tumour growth. Bcl-2 is an oncogene which promotes tumour progression by specifically inhibiting programmed cell death. Bcl-2 oncoprotein was measured using flow cytometry in 42 surgically excised regional lymph node metastases from patients with a median follow-up of 45 months. Fifteen patients in the study were found to have bcl-2 expression which was associated with significantly shorter survival (log-rank test, P<0.002). In addition, multivariate analysis confirmed the predictive value of bcl-2 independent of other established prognostic markers (chi(2)=7.02, P<0.01). Oncogenic control of programmed cell death is therefore important in melanoma progression and bcl-2 measurement provides a useful marker of prognosis for regional lymph node metastases.

Poorly differentiated oxyphilic (Hurthle cell) carcinomas of the thyroid

A series of 60 cases of oxyphilic (Hurthle cell) carcinomas (HCC) of the thyroid were reviewed to determine whether it is possible to correlate morphologic and clinical features as a means of assessing prognosis. Twenty cases showing predominant solid or trabecular patterns (as described in poorly differentiated carcinomas with a follicular pattern) were selected and the clinicopathological features were investigated. Based on cell size, two groups of solid or trabecular HCCs were identified: The first group (17 cases) was made up of typical large granular oxyphilic cells, and the second (three cases) had small oxyphilic cells. All tumors were reactive for thyroglobulin and for a mitochondrial antigen, selectively marking oxyphilic, mitochondrial-rich cells. Nuclear pleomorphism in individual cells was a common feature, but foci of anaplastic carcinoma were never found. Four cases overexpressed p53 protein and 10 expressed bcl-2 gene product. At follow-up, among the high-stage (pT3-pT4) tumors, seven patients had recurrences or metastases, six of whom were alive with disease or died of disease. In the control group of HCC with predominant follicular patterns, only one of 40 cases had a fatal outcome. The difference was statistically significant. Small-cell patterns and a p53 protein-positive/bcl-2 gene product negative phenotype were features of clinically aggressive HCC cases. We suggest that within the spectrum of oxyphilic (Hurthle cell) tumors, poorly differentiated HCC showing solid or trabecular patterns are a distinct group, based on both morphological and clinical features.

Clinicopathologic study of primary gastric lymphoma of B cell phenotype with special reference to low-grade B cell lymphoma of mucosa-associated lymphoid tissue among the Japanese

Resection specimens from 83 patients with primary gastric lymphoma (PGL) of B cell phenotype at stage IE and at stage IIE according to the Ann Arbor classification were investigated. Histologically, these lymphomas could be divided into four types: Type I lesions (n = 24) were entirely made up of MALT lymphoma; Type II lesions (n = 13) were predominantly MALT lymphoma containing one to a few foci of high-grade B cell lymphoma; Type III lesions (n = 22) consisted largely of high-grade lymphoma with small areas of low-grade MALT lymphoma; and Type IV lesions (n = 24) were pure high-grade B cell lymphoma, mostly of the large cell type. All patients had undergone primary gastric resection, and 14 received additional chemotherapy (n = 12), or both chemotherapy and radiotherapy (n = 2). The survival probability was significantly higher for Types I and II lymphomas than for Types III and IV tumors (P < 0.05 by the generalized Wilcoxon test). According to The General Rules for the Gastric Cancer Study by the Japanese Research Society for Gastric Cancer, the stage of disease showed a clear distinction between each of them (P < 0.01 by the generalized Wilcoxon test). This staging method seemed to serve well as a prognostic indicator. The histological typing of the PGL of the present series also seemed to correlate with the gross appearance, pathologic stage and prognosis. Furthermore, the expression of cyclin D1, bcl-2 and p53 protein, and PCNA was immunohistochemically investigated in 42 cases of the present series. Most of the low-grade PGL (Types I and II) had less than 60% PCNA-positive cells, whereas the high-grade PGL (Types III and IV) had more than 60% positive cells. In a study for cyclin D1 protein, no cases showed the nuclear staining pattern characteristic for mantle cell lymphoma, and the cytoplasmic staining frequently observed in the node-based large B cell lymphoma was seldom identified in the PGL. This discrepancy might suggest a lineage difference among the morphologically similar, but site-different, lymphomas. On the other hand, bcl-2 protein overexpression was almost equal in frequency between the gastric and node-based high-grade B cell lymphomas. This is in contrast to the reports from Western countries, in which the majority of high-grade gastric tumors were bcl-2 negative.