Cells are eliminated in a variety of physiological settings by apoptosis, a genetically encoded process of cellular suicide. Apoptosis comprises an intrinsic cellular defence against tumorigenesis, which, when suppressed, may contribute to the development of malignancies. The bcl-2 oncogene, which is activated in follicular lymphomas, functions as a potent suppressor of apoptosis under diverse conditions. Here we describe the complementary DNA cloning and functional analysis of a new Bcl-2 homologue, Bak, which promotes cell death and counteracts the protection from apoptosis provided by Bcl-2. Moreover, enforced expression of Bak induces rapid and extensive apoptosis of serum-deprived fibroblasts. This raises the possibility that Bak is directly involved in activating the cell death machinery.

A monoclonal antibody 1-6E10 against the protein product p62c-myc of the c-myc oncogene was used to assess, by immunohistology, a variety of non-neoplastic and preneoplastic disorders of gastric and colonic mucosa. There were low levels of expression of the c-myc oncogenic product in normal gastric and colonic tissue. In gastric mucosa, increased expression was observed with inflammatory, metaplastic and dysplastic histological appearances. In the normal colon low levels of expression were observed, but there was increased expression in inflammatory disorders including Crohn's disease and ulcerative colitis. There was also increased expression in colonic dysplasia associated with ulcerative colitis. The oncogene product was localized in the cytoplasm, nuclei and Golgi apparatus. C-myc 1-6E10 may therefore be used as a marker to identify the cellular proliferative response in gastric and colonic mucosa that is associated with inflammation as well as potentially neoplastic hyperproliferative states.

Summary The c-myc nuclear associated oncoprotein has been quantitated simultaneously with DNA in nuclei extracted from archival biopsies of uterine cervix neoplasia. The oncoprotein and DNA were measured fluorimetrically in a flow cytometer using a mouse monoclonal antibody (MYC I-6E10) and propidium iodide. Normal biopsies exhibited higher oncoprotein levels than carcinomas (P<0.00001). Furthermore, the maximum fluorescence signal in the normal tissue occurred at a lower antibody concentration compared with tumour tissue. There was no correlation between oncoprotein levels and histological grade, stage of disease, age of the patients or prognosis in the carcinomas. Aneuploidy, defined as a distinct second peak separate from the diploid distribution, was not a significant feature. The c-myc oncoprotein nuclear content does not appear to be a prognostic indicator in carcinoma of the cervix from the results of these studies but there is clearly diagnostic potential, particularly for automated analysis of cervical screening.Oncogcincs are associated with proliferation control. The csis gene encodes a subunit of platelet derived growth factor (Doolittle et al., 1983; Waterfield et al., 1983). v-erb B and cfms respectively encode the intracellular domain of epidermal growth factor receptor (Downward et al., 1984) and the transmembrane receptor for the macrophage colony stimulating factor, CSF 1, (Scherr et al., 1985). Expression of the c-myc gene is associated with the transition from a quiescent to a stimulated state (Kelly et al., 1983(Kelly et al., , 1984Makino et al., 1984;Greenberg & Ziff, 1984;Hann et al., 1985;Rabbitts et al., 1985).A series of mouse monoclonal antibodies which recognise the c-myc nuclear associated oncoprotein, p62c-mYc, (Evan & Hancock, 1985) have been developed . One of these antibodies has been used for histological localization of p62c-myc in both testicular cancer and in colonic neoplasia using immunocytochemical techniques. Quantitative methods have now been developed to assay nuclear associated p62cmvc in individual nuclei extracted from archival biopsies using flow cytometry . These methods have been used to analyse data in testicular cancer and colonic neoplasia (Watson et al., submitted). In this paper we examine the p62c-mYc nuclear content in normal and neoplastic cervical biopsies. Patients and methods PatientsA total of 127 patients attending the Weston Park Hospital Radiotherapy Department, Sheffield between 1971 and 1978 were included in the study. The only criteria of entry were that sufficient wax embedded punch biopsy material was available for the assay and that there were complete followup data. Sixty-four biopsies were from invasive carcinoma and 29 were from normal cervix. The remaining patients had cervical intraepithelial neoplasia (CIN) disease where 11, 9 and 14 were grades I, II and III respectively.Anti-p62c-mYc antibody Full details of the methods for production of the antip62c-mYc antibody are published elsewhere . Briefly, synthetic peptides were constructe...

Summary The 62 kDa protein product of the c-myc oncogene (p62 c-myc) is thought to be involved in the control of normal cellular proliferation and differentiation. We have measured oncoprotein levels using a flow cytometric assay in 141 operable breast cancers and have correlated levels with prognostic variables, patient survival and disease free intervals. High levels of p62 c-myc were associated with well differentiated tumours.There was no correlation with tumour DNA index, lymph node or oestrogen receptor status. C-myc oncoprotein levels were not predictive of patient survival or disease free interval. This relationship of oncoprotein levels with tumour histological grade is in keeping with the suggestion that the c-myc oncogene is important in the control of cellular differentiation. The other findings imply that measurement of c-myc oncoprotein levels does not yield useful prognostic information.Cellular oncogenes resembling viral oncogenes are present in normal cells where they encode proteins that act as receptors, intracellular signal transducers or growth factors. Oncogene products are thus important in the control of normal cellular development and division. Changes in oncogene expression occur during normal wound repair (Goyette et al., 1983) and embryogenesis (Muller et al., 1982). Changes in oncogene control and expression may also lead to, or be associated with, malignant transformation.The c-myc oncoprotein is associated with cell division and differentiation as c-myc mRNA increases as culture cells are stimulated into division (Kelly et al., 1983). It has a short half-life and has been shown to be nuclear associated (Persson & Leder, 1984), which is in keeping with a proposed role in cell cycle control. The aim of this study was to confirm that c-myc oncoprotein levels could be quantified in the nuclei of breast cancers. We also wished to determine whether a correlation existed between oncoprotein levels, tumour prognostic factors, patient survival and disease-free interval. Patients and methodsOne hundred and forty-one patients were studied. All had undergone simple or subcutaneous mastectomy as the primary treatment for their breast cancer between 1974 and 1976 at the Nottingham City Hospital. Lymph node sampling was performed in all cases. The nodes sampled were low axillary, apical axillary and internal mammary (via the second interspace) at the time of initial surgery. Three lymph node stages can be identified based on the involvement of nodes with metastatic tumour. These are: stage 1, no nodal involvement; stage 2, low axillary node involvement alone; stage 3, apical or internal mammary node involved alone or in any other combination.Antibodies to the c-myc oncoprotein have been generated by peptide immunisation . The DNA sequence of the c-myc gene was used to deduce the amino acid sequence of the oncoprotein, and mice were immunised to produce monoclonal antibodies. A number of antibodies have been produced and one of them can be used to detect p62 c-myc in archival pathological material...

SUMMARY Monoclonal antibodies raised by synthetic peptide immunisation were used to determine the distribution of the protein product of the c-myc gene by immunocytochemical staining of archival wax embedded material from patients with familial adenomatous polyposis. Polyps from 18 cases of familial adenomatous polyposis, 10 of whom had developed malignant change, and 30 normal control colonic biopsy specimens were examined. A consistent staining pattern was observed in normal mucosa; nuclear staining in the basal proliferative zone; mixed nuclear and cytoplasmic staining in the maturation zone; and cytoplasmic localisation in the surface mature zone. In contrast, the polyps and carcinomata showed a mixed pattern of cytoplasmic and nuclear localisation in the basal proliferative zone with nuclear persistence throughout the crypts to the surface mature zone. This abnormal distribution of the c-myc oncogene product may have a role in the evolution of polyps and their subsequent malignant transformation into familial adenomatous polyposis.