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OBJECTIVE To investigate the effects of microRNA-15a (miR-15a) on the growth of the lymphoma Raji cell line. METHODS A eukaryotic expression vector of precursor miR-15a (pre-miR-15a) was constructed. Paired oligonucleotides for pre-miR-15a expression were designed and synthesized chemically. Annealed oligonucleotides were inserted into a pGCSIL-GFP vector under a U6 promoter to construct a pre-miR-15a expression plasmid. Oligonucleotides with a scrambled sequence which were used as a negative control were also constructed into the pGCSIL-GFP vector. A recombinant expression vector was identified through PCR and sequencing. A pre-miR-15a expression plasmid and a negative control plasmid were all transferred into Raji cells with lipofectamine 2000. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was employed to explore expression of miR-15a. The expression levels of the protein were assayed via immunofl uorescence. The growth effect of Raji cells was measured by CCK8 assay. Apoptosis was determined using Hoechst dyeing and flow cytometry. The growth-inhibitory effect on Raji cells was measured using a CCK8 assay.RESULTS The results showed that the insertion sequence was correct. The expression level of miR-15a was obviously higher in Raji cells transferred with pre-miR-15a plasmid than in the blank group and in the negative control group. After Raji cells were transferred with the pre-miR-15a expression plasmid for 48 h, Bcl-2 protein expression levels were obviously decreased，which indicated that there was a significant difference as compared with the negative control group and blank group (P < 0.05). The CCK8 assay showed that transfection of pre-miR-15a expression plasmid decreased the cell growth at 24, 48 and 72 h post-transfection. After Raji cells were transferred with pre-miR-15a expression plasmid, apoptotic cells can be seen with Hoechst dyeing, and the cell apoptotic rate was obviously higher than that in blank group and negative control group. CONCLUSION Pre-miR-15a can induce apoptosis and inhibit the growth of Raji cells.

Systemic lupus erythematosus is a prototypical autoimmune disease characterized by the deregulation of T and B cells, tissue infiltration by mononuclear cells, tissue damage and the production of autoantibodies. There is a consensus that accelerated apoptosis of circulating lymphocytes and/or impaired clearance of apoptotic bodies may increase the amount of nuclear antigens presented to T lymphocytes. This process is accompanied by autoimmune responses that can lead to the development of lupus. The dysfunction of apoptosis may be a direct consequence of alterations in proteins/genes such as Fas, Bcl-2 and C1q. Increased expression of Fas antigen could intensify the exposure of hidden antigens. The overexpression of Bcl-2 protein might inhibit the removal of auto-reactive cells, and the lack of C1q could impair the clearance of self-antigens. The complete knowledge of the role of apoptosis components in the etiopathogenesis of lupus could lead to the development of new therapies targeting the apoptotic threshold, which could result in a more specific and effective disease response compared to global immunosuppression. This review summarizes the role of each component of the apoptotic process in the pathogenesis of lupus.

Aim: The aim of this study was to analyze the presence of the anti-apoptotic protein bcl-2 in oral squamous cell carcinoma and determine its potential role in the development and progression of this type of tumor. Materials and methods: The expression of bcl-2 was determined in 28 paraffin blocks of oral squamous cell carcinoma using the immunohistochemical method. The percentage of the immuno-reactive cells in positively stained tumor regions was determined using the microscopic analysis and Ozaria software. Results: Positive immunohistochemical test was observed in 19 out of 28 samples (68%) as follows: in 11 samples there was a low (+), in four a moderate (++) and in the last four a high percentage (+++) of stained cells. In the group of patients at the low stage of the disease (T2), 50% of tumor samples showed bcl-2 protein expression whereas in the higher stages (T3 and T4) of positively stained samples, this percentage was 67%. There was a trend of an increasing number of cells with positive bcl-2 staining in the tumors of higher clinical stages but not the level of bcl-2 protein expression. Conclusion: Both parameters, the presence of bcl-2 staining and the percentage of cells with bcl-2 immunoexpression, may act as additional prognostic parameters that indicate an increased proliferative tumor potential., Cilj ove studije bio je analiza prisustva antiapoptotskog proteina bcl-2 u skvamocelularnom karcinomu usne regije i procena njegove eventualne uloge u razvoju i progresiji ove vrste tumora. Materijal i metode: Na uzorku od 28 parafinskih blokova skvamocelularnog karcinoma usne regije, imunohistohemijskom metodom ispitan je ekspresioni status bcl-2 proteina. Mikroskopskom analizom i primenom softvera- Ozaria određen je procenat imunoreaktivnih ćelija u pozitivno obojenim tumorskim regijama. Rezultat: Pozitivnu imunohistohemijsku obojenost pokazalo je 19 od 28 uzoraka (68%) i to: 11 je bilo sa niskim (+), 4 sa srednjim (++) i 4 sa visokim procentom (+++) obojenih ćelija. U grupi pacijenata niskog stadijuma (T2) 50 % uzoraka tumora je pokazivalo ekspresiju bcl-2 proteina dok je u višim stadijumima (T3 i T4) pozitivnih uzoraka bilo 67%. Postojao je trend porasta broja ćelija sa pozitivnom bcl-2 obojenošću kod tumora u višim kliničkim stadijumima, ali ne i povećan nivo ekspresije bcl-2 proteina. Zaključak: Oba parametra, prisustvo bcl-2 obojenosti i procenat ćelija sa bcl-2 imunoekspresijom, mogu predstavljati dopunske prognostičke parametre koji ukazuju na povećan proliferativni potencijal tumora.

The spatial and temporal distribution as well as ultrastructural and biochemical characteristics of apoptotic and mitotic cells during human eye development were investigated in 14 human conceptuses of 4-9 postovulatory weeks, using electron and light microscopy. In the 5th developmental week, apoptotic and mitotic cells were found in the neuroepithelium of the optic cup and stalk, being the most numerous at the borderline between the two layers of the optic cup, and at the place of transition of the optic cup into stalk. They were also found at the region of detachment of the lens pit from the surface ectoderm. In the later developmental stages (the 6th-the 9th week), apoptotic and mitotic cells were observed in the neural retina and the anterior lens epithelium. Throughout all stages examined, mitotic cells were found exclusively adjacent to the lumen either of the intraretinal space or the optic stalk ventricle, or were restricted to the superficial epithelial layer of the lens primordium. Unlike mitotic cells, apoptotic cells occurred throughout the whole width both of the neuroepithelium and the surface epithelium. Ultrastructurally, apoptotic cells were characterised by round- or crescent-shaped condensations of chromatin near the nuclear membrane, while in the more advanced stages of apoptosis by apoptotic bodies. The distribution of caspase-3-positive cells coincided with the location of apoptotic cells described by morphological techniques indicating that the caspase-3-dependent apoptotic pathway operates during the all stages of human eye development. The location of cells positive for anti-apoptotic bcl-2 protein was in accordance with the regions of eye with high mitotic activity, confirming the role of bcl-2 in protecting cells from apoptosis. In the earliest stage of eye development, apoptosis and mitosis might be associated with the sculpturing of the walls of optic cup and stalk, while high mitotic activity along the intraretinal space and optic stalk ventricle indicates its role in the gradual luminal closure. These processes also participate in the detachment of the lens pit epithelium from the surface ectoderm as well as in further closure of the lens vesicle. Later on, both processes seem to be involved in the neural retina differentiation, lens morphogenesis and secondary lens fibre differentiation.

Purpose: The purpose of this study was to assess the prognostic value of the expression of p53 and bcl-2, the apoptotic index and the expression of topoisomerase II alpha in patients with inoperable non-small cell lung cancer (NSCLC) treated with high dose radiotherapy.Patients and methods: A number of 161 patients with inoperable NSCLC treated with high dose radiotherapy (60 Gy) were included. Immunohistochemical analysis was used to assess the expression of nuclear p53-protein, topoisomerase II alpha and cytoplasmatic expression of bcl-2, while spontaneous apoptosis was assessed using in situ labeling. The minimal follow up period was 2 years.Results: Local control did not only depend on the presence of p53 expression, but also on the proportion of p53 positive cells. The most important prognostic factor was the apoptotic index. A high apoptotic index was associated with worse local control, more distant metastases and a significantly worse overall survival. No association was noted between the expression of bcl-2 and topoisomerase II alpha with any of the endpoints.Conclusion: This study indicates that p53 expression and the apoptotic index are prognostic factors with regard to local control in patients with inoperable NSCLC treated with radiotherapy and by combining these 2 factors, a clinically relevant estimation of the local control probability can be made. The apoptotic index turned out to be the only factor significantly related to survival. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.

p53 and Bcl-2 are two important factors related to apoptosis and tumorigenesis. In this study, a series of 52 cases of pancreatic carcinoma (PC) were investigated using an immunohistochemical assay to determine whether altered expression of Bcl-2 and p53 has an impact on the progression of this malignancy. Cytoplasmic immunoreactivity for Bcl-2 and nuclear staining of p53 was found in 12 (23.1%) and 32 (63.5%) cases of PC respectively. Furthermore, an inverse correlation between the expression of p53 and Bcl-2 existed in this series (P < 0.01). In a subgroup, the proportion of tumours showing that p53-positive and Bcl-2-negative staining was increased with increasing histological grade and clinical stage (P < 0.05), and moreover, the survival period of those patients whose tumour had this staining was shorter than those with other staining patterns of combined p53 and Bcl-2 (P < 0.05). Therefore, it is concluded that simultaneously aberrant expression of Bcl-2 and p53 may confer PC with more malignant clinicopathological characteristics. © 1999 Cancer Research Campaign

The presence of the BCL-2 protein was studied in nine non-Hodgkin's lymphomas with testicular localisation. A consistent presence of the BCL-2 protein was found. The chromosomal translocation (14;18) was seen neither by cytogenetic analysis (n = 4) nor by polymerase chain reaction amplification and Southern blotting (n = 9). Therefore, this translocation is not responsible for the presence of the BCL-2 protein in non-Hodgkin's lymphomas with testicular localisation. We suggest that the presence of the BCL-2 protein in these lymphomas is related to the differentiation stage of the B-lymphocytes or may play a role in the pathogenesis of these lymphomas. The consistent finding of the BCL-2 protein in lymphomas with testicular localisation may support the clinical observation that these lymphomas are a separate entity.

The aim of our study was to estimate the surface expressions of CD95 (APO-1/Fas) antigen and the intracellular expressions of anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax in CD4(+)CD25(+)FoxP3(+) T regulatory lymphocytes (Tregs) as well as the percentage of CD8(+)CD28(+) T cytotoxic cells in peripheral blood of patients with pre-eclampsia in comparison with healthy pregnant women in the third trimester of physiological pregnancy. Twenty-four women with pre-eclampsia and 20 normal third trimester pregnant women were included in the study. The lymphocytes were isolated from peripheral blood samples and labeled with monoclonal antibodies. The expressions of surface antigens and intracellular proteins were estimated using flow cytometry. The population of CD4(+)CD25(+)FoxP3(+) Treg cells was significantly lower in peripheral blood of patients with pre-eclampsia when compared to normal third trimester pregnant women. The percentages of CD4(+)CD25(+)FoxP3(+) Treg cells that express Bcl-2 protein were significantly lower in peripheral blood of patients with pre-eclampsia when compared to healthy pregnant women, whereas the percentages of CD4(+)CD25(+)FoxP3(+) Treg cells with the expressions of Bax protein did not differ in both groups. Moreover, the mean fluorescence intensity (MFI) of Bcl-2 protein in CD4(+)CD25(+)FoxP3(+) Treg cells was significantly lower and MFI of Bax protein significantly higher in pre-eclampsia when compared to the control group. The percentage of CD8(+)CD28(+) T cells did not differ in both studied groups but MFI of CD28 antigen on T CD8(+) cells was significantly higher in pre-eclampsia when compared to the control group. The obtained results suggest that the deficit of CD4(+)CD25(+)FoxP3(+) Treg lymphocytes which is observed in pre-eclampsia may be associated with altered apoptosis signaling in Tregs.

Background and Objectives: The product of bcl-2 gene, bcl-2 protein, an anti-apoptotic protein, is known to be over-expressed in potentially malignant disorders and squamous cell carcinoma (SCC) of the oral cavity. The aim of this study is to compare the topographical aspect and degree of bcl-2 over-expression in potentially malignant disorders including leukoplakia, oral submucous fibrosis (OSMF), and oral lichen planus (OLP), with that of the oral squamous cell carcinoma (OSCC), and to determine whether bcl-2 protein can be considered as a tumor marker. Materials and Methods : A group of 60 histo-pathologically diagnosed, formalin-fixed, paraffin embedded tissue samples was included in the study. The study group was further subdivided into four groups: Group I, consisting of oral leukoplakia; Group II, OSMF; Group III, OLP and Group IV, OSCC. These samples were collected from Government Dental College, Bangalore, and then subjected to immunohistochemical (IHC) staining using indirect immunoenzyme labeled streptavidin biotin (LSAB) method. Results : Out of 30 cases of OSCC: 11 (36.7%) cases showed greater supra-basal keratinocyte staining; 15 (50%) cases showed greater number of positive cells in the basal cell layer, with relatively less number of supra-basal cells showing positive staining; and, rest of the 4 (13.3%) cases did not show convincing staining. Among the total 30 cases of potentially malignant disorders: 10 each of leukoplakia, OSMF and OLP, 2 (20%), 2 (20%), 4 (40%) of the cases showed greater supra-basal cell layer positive staining and 8 (80%), 6 (60%), 6 (60%) of them showed greater basal cell staining, respectively. Two cases of OSMF did not show convincing staining. In the cases that were bcl-2 positive: 2 (6.67%) of the OSCC, 3 (30%) of leukoplakia, 2 (20%) of OSMF and 1 (10%) of OLP, showed more than 50% of the cells positive. 25-50% cells were positive in 21 (70%) of OSCC, 6 (60%) of leukoplakia, 4 (40%) of OSMF and 6 (60%) of OLP cases. 10-25% of cells were positive in 4 (13.3%) of OSCC, 1(10%) of leukoplakia, 2 (20%) of OSMF and 3 (30%) of OLP cases. Less than 10% of cells were positive in 3 (10%) of OSCC and 2 (20%) of OSMF cases. Clinical Significance and Conclusion : As definite number of cases showed bcl-2 over expression in our study, the role of bcl-2 in the development and progression of oral neoplasia needs further investigation along with other oncogenes.

Background: Apoptosis related proteins in early staged NSCLC seem to have prognostic value. We studied the value of a combination of eight of those proteins in advanced NSCLC.Patients and methods: Bronchoscopically procured tumor biopsies of NSCLC patients were stained immunohistochemically and rated for expression of eight different cellular proteins. Patients were treated with 60 Gy radiotherapy with or without carboplatin as radiosensitizer.Results: Apoptotic proteins in tumors that showed positive staining were the highest for Bax (99%), Fas (92%), FasL (87%), Rb (87%), p21 (WAF1) (73%), and p53 (70%), and the lowest for c-myc (58%) and Bcl-2 (58%). In the Cox regression analysis Bcl-2 positivity (RR=0.61, 95% Cl, 0.37-0.98, p=0.04) was predictive for overall survival. Only Bcl-2 staining percentage (RR10 (RR associated with an increase in stained cells of 10%) = 0.93, 95% Cl, 0.89-0.99), p53 (RR10 = 0.94, 95% Cl, 0.89-0.99) and FasL (RR10 = 0.92, 95% Cl, 0.86-0.99) were predictive for a longer progression-free survival. No specific constellation of apoptotic proteins was associated with tumor response.Conclusion: Bcl-2 expression in tumor tissue of patients with unresectable NSCLC predicts a better overall survival, while Bcl-2, p53, and FasL expressions predict for a longer progression-free survival. (C) 2006 Etsevier Ireland Ltd. All rights reserved.

We recently proposed that Th1 and Th2 cytokines exert opposite effects on the pathogenesis and clinical outcome of organ-specific autoimmunity by altering the expression of genes involved in target cell survival. Because a Th2 response against tumors is associated with poor prognosis, we investigated the ability of IL-4 to protect tumor cells from death receptor- and chemotherapy-induced apoptosis. We found that IL-4 treatment significantly reduced CD95 (Fas/APO-1)- and chemotherapeutic drug-induced apoptosis in prostate, breast, and bladder tumor cell lines. Analysis of antiapoptotic protein expression revealed that IL-4 stimulation resulted in up-regulation of cellular (c) FLIP/FLAME-1 and Bcl-xL. Exogenous expression of cFLIP/FLAME-1 inhibited apoptosis induced by CD95 and to a lesser extent by chemotherapy, while tumor cells transduced with Bcl-xL were substantially protected both from CD95 and chemotherapeutic drug stimulation. Moreover, consistent IL-4 production and high expression of both cFLIP/FLAME-1 and Bcl-xL were observed in primary prostate, breast, and bladder cancer in vivo. Finally, primary breast cancer cells acquired sensitivity to apoptosis in vitro only in the absence of IL-4. Thus, IL-4 protects tumor cells from CD95- and chemotherapy-induced apoptosis through the up-regulation of antiapoptotic proteins such as cFLIP/FLAME-1 and Bcl-xL. These findings may provide useful information for the development of therapeutic strategies aimed at restoring the functionality of apoptotic pathways in tumor cells.

Background: Dicer, an RNase III-type endonuclease, is the key enzyme involved in RNA interference and microRNA pathways. Aberrant expression of Dicer is reported in several human cancers. Our aim was to assess the prognostic role of Dicer in breast cancer. Methods: The entire series comprised 666 invasive breast cancers (IBCs), 480 DCIS cases (397 associated with IBC and 83 pure DCIS) and 305 lymph node metastases. Cytoplasmic Dicer expression by immunohistochemistry was scored as negative (no staining) and positive (weak, moderate or strong staining). Results: Dicer staining was assessable in 446 IBC, 128 DCIS and 101 lymph node metastases. Expression of Dicer was observed in 33% (145/446) of IBCs, 34% (44/128) of DCIS and 57% (58/101) of lymph node metastases. Dicer expression was increased in nodal metastases compared to primary tumours (p< 0.001); and was associated with ER negativity (p

Photodynamic therapy (PDT) in early squamous cell carcinoma of the bronchus has been shown to result in complete response (CR) and cure. However, local recurrence after PDT develops frequently even after complete remission. Because the effect of PDT had been reported to depend on apoptosis, and apoptosis is inhibited by bcl-2 protein, the relationship between the expression of bcl-2 protein and local recurrence after PDT was examined immunohistochemically. From 1983 to 1997, 50 patients with 59 early squamous cell carcinoma of the bronchus received PDT, and a CR was obtained in 43 lesions (72.8%). As there was no recurrence among tumours that were disease-free for more than 2 years, in this study the tumours were defined as cured when recurrence did not occur 2 years subsequent to the receiving of PDT. Of these CR lesions, 31 carcinomas (53.4%) resulted in a cure. Bcl-2 immunoreactivity was detected in 23 tumours (46.9%) and p53 immunoreactivity was detected in 22 tumours (44.9%). When all tumours were divided into either a large tumour with a longitudinal tumour length of 10 mm or more, or a small tumour with a length of less than 10 mm, the large tumour expressed more bcl-2 protein than the small tumour (P = 0.0155). The degree of bcl-2 expression was significantly related with tumour size (P = 0.0155). The expression of bcl-2 and p53 protein was not associated with the cure rate due to PDT. Tumour length and T status in TNM staging were significantly related to the cure by univariate analysis. T status was the only predictor of the cure according to mutivariate analysis. Of 42 CR lesions, the expression of neither bcl-2 nor p53 protein was associated with local recurrence; only T status was significantly associated (P = 0.008). The relationship between the expression of oncoprotein and local recurrence after PDT was not documented in this study. The success of PDT may depend on the exact assessment of tumour size under optimized PDT illumination. © 2000 Cancer Research Campaign

In this work, we examined the expression of Bcl-2 protein in myeloid leukaemia (ML) cells and the effect of UVC-light on the expression level. The protein of bcl-2 oncogene was detected by immunocytochemical method. In spleen cells of healthy RFM donors was detected 34.3% of Bcl-2 positive cells. When leukaemia came to the non terminal phase (NTP) more than 50% of cells expressed this protein. However, in terminal phase (TP) of leukaemia growth, only 24.4% Bcl-2 positive cells was determined. After UVC irradiation, the expression of Bcl-2 protein was significantly higher in spleen cells of healthy donors. However, UVC light did not change the expression of Bcl-2 in cells of both investigated phases of ML growth, Bcl-2 protein may be involved in the resistance of Ml cells to UVC light.

The bcl-2 protein plays a role in the regulation of programmed cell death (PCD), overriding apoptosis. Its expression has been reported in breast ductal cells, where it is believed to be involved in the hormonal regulation of hyperplasia and involution. To date, bcl-2 gene product has not been investigated on breast cancer FNA. The expression of bcl-2 protein was evaluated using an immunoalkaline phosphatase technique in 54 pre-operative breast cancer aspirates and in paraffin-embedded sections from 20 matched surgical specimens. A high rate of bcl-2 protein expression was found on FNA samples (65%) and on the corresponding tissue sections (60%); there was a nearly absolute concordance in the two specimens, with 19/20 (95%) cases showing a concordant staining. These findings concur with the view that bcl-2 gene is frequently expressed in breast cancer, possibly through a hormonal-dependent pathway.

Background: Solid ameloblastoma (SAB) is an invasive tumor which infiltrates adjacent normal tissues. Adenomatoid odontogenic tumor is a noninvasive tumor and never infiltrates surrounding normal tissues. The purpose of this study was to determine the biological behavior of these two epithelial odontogenic neoplasm by detecting Ki-67 and Bcl-2, which are mitotic and anti apoptotic markers respectively. Materials and Methods: In this analytical retrospective study, 16 samples of SAB and 16 samples of adenomatoid odontogenic tumor were selected. The samples were deparafinized and antigens were retrieved. Immunohistochemistry technique was applied for evaluation of these two markers. Monoclonal antibodies MIB1 and Bcl-2 were used to detect Ki-67 and Bcl-2 protein respectively, then the labeling index (LI) was calculated for both markers according to cellular staining. Data were analyzed by “ t ” test, ( P< 0.05). Results: The mean values of LI for Ki-67 in SAB and Adenomatiod odontogenic tumor (AOT) were 4 and 1% respectively and for Bcl-2 in SAB and AOT were 63 and 26% respectively. The indices of both markers were higher in SAB compared to AOT ( P< 0.05). Conclusions: Higher percentage of these two markers in SAB compared to AOT confirms the aggressive behavior of SAB and the hamartomatosis behavior of AOT. Key Words: Adenomatoid odontogenic tumor, ameloblastoma, Bcl-2 protein, immunohistochemistry, Ki-67 antigene

The interchromosomal 14;18 translocation occurs in approximately 70-80% of follicular lymphomas and in a lower proportion of high-grade non-Hodgkin lymphomas of the lymph nodes. This translocation results in the fusion of the bcl-2 oncogene on chromosome 18 with immunoglobulin heavy chain genes on chromosome 14, and in the expression of higher amounts of normal bcl-2 protein. We studied bcl-2 expression in biopsies of 108 patients with benign and malignant cutaneous lymphoproliferative diseases (B-cell lymphoma, primary cutaneous, 42; secondary cutaneous, 21; primary cutaneous T-cell lymphoma, 21; B-cell pseudolymphoma, 24), using a monoclonal anti-bcl-2 antibody on paraffin-embedded tissue sections, bcl-2 protein was detected immunohistochemically in 16 of 63 cases of cutaneous B-cell lymphoma, whereas cutaneous T-cell lymphomas and B-cell pseudolymphomas were negative. The proportion of bcl-2 protein expression was significantly higher in secondary (11/21) than in primary cutaneous B-cell lymphomas (5/42; chi 2 test, p < 0.001). Biopsies from 25 of these patients (B-cell lymphoma, 22; B-cell pseudolymphoma, three) were analyzed previously on the molecular level for the t(14;18), using polymerase chain reaction amplification of DNA obtained from paraffin-embedded sections. In four of 11 cases of bcl-2 protein-positive B-cell lymphoma (primary, one; secondary, three) the t(14;18) was detected by polymerase chain reaction. All other cases of B-cell lymphoma, including seven cases where bcl-2 protein was detected by immunohistology, and B-cell pseudolymphoma were negative. These results demonstrate: 1) bcl-2 protein is expressed in a small portion of cutaneous B-cell lymphomas; 2) bcl-2 protein expression is significantly more frequent in secondary than in primary cutaneous B-cell lymphoma; 3) only approximately one-third of cases expressing the bcl-2 protein are characterized also by the t(14;18). bcl-2 protein expression might indicate that the cutaneous manifestation of the lymphoma represents a secondary spread from a node-based lymphoma.

The finding that the heterologous expression of Bcl-2 proteins in yeast elicits effects that resemble their roles in metazoan apoptosis has contributed to the increasing use of this organism as a model for the study of apoptotic regulation. The pro-apoptotic Bax protein, for example, localizes to the yeast mitochondria, where it acts to promote alterations in mitochondrial physiology and cell death, similar to its ascribed mode of action in higher organisms. These observations lead to the hypothesis that the heterologous Bcl-2 proteins impinge on conserved elements of the apoptotic machinery in yeast. We herein provide a retrospective of the studies aimed at both testing this general hypothesis and investigating the mechanisms of the Bcl-2 proteins using yeast, with a particular emphasis on Bax. We also discuss the evidence for pleiotropic roles of Bax in yeast apoptosis.

The presence of the BCL-2 protein was studied in nine non-Hodgkin's lymphomas with testicular localisation. A consistent presence of the BCL-2 protein was found. The chromosomal translocation (14;18) was seen neither by cytogenetic analysis (n = 4) nor by polymerase chain reaction amplification and Southern blotting (n = 9). Therefore, this translocation is not responsible for the presence of the BCL-2 protein in non-Hodgkin's lymphomas with testicular localisation. We suggest that the presence of the BCL-2 protein in these lymphomas is related to the differentiation stage of the B-lymphocytes or may play a role in the pathogenesis of these lymphomas. The consistent finding of the BCL-2 protein in lymphomas with testicular localisation may support the clinical observation that these lymphomas are a separate entity.