We investigated aberrant p53 expression in 81 cases of cervical intra-epithelial neoplasias (CIN) using a polyclonal antibody CM-1. The presence of human papillomavirus (HPV) DNA was evaluated by in situ and dot blot hybridization. Significant (more than 1% of cells positive) p53 positivity was found in three cases (4%) of which only one contained HPV DNA. In an additional nine cases, occasional p53 staining was found in basal epithelial cells, frequently associated with epithelial hyperplasia and increased subepithelial inflammation. The results show that aberrant p53 expression is an infrequent finding in CIN lesions. It can be seen in lesions both with and without HPV infection. Most importantly, there was no p53 expression in most cases of HPV-negative CIN, suggesting that p53 inactivation is not an obligatory step in the development of cervical dysplasia. However, our findings do not exclude the possibility that p53 mutations can occur later in the course of cervical carcinogenesis.
In order to test the hypothesis that increased apoptotic activity is connected with neuroendocrine differentiation and low differentiation degree in large cell carcinoma (LCLC) and is regulated by bcl-2 family proteins, we analysed the extent of apoptosis and tumor necrosis and their relation to the expression of bcl-2, bax, bak and mcl-1 in 35 LCLCs, of which 20 were classified as large cell neuroendocrine lung carcinomas (LCNEC) and 15 as large cell non-neuroendocrine lung carcinomas (LCNNEC). The extent of apoptosis was determined by detecting and counting the relative and absolute numbers of apoptotic cells and bodies using in situ 3 -end labelling of the apoptotic DNA. The extent and intensity of expression of the bcl-2, bax, bak and mcl-1 proteins were studied by immunohistochemistry. Also the relative volume density of necrosis was evaluated and correlated with the other parameters. Finally, all the parameters were evaluated as prognostic markers and correlated with data on the survival of the patients. Relatively high apoptotic indices were seen in both tumor types (average for both 2.53%, range 0.09 27.01%). Significantly higher bcl-2 and bak indices were detected more often in LCNECs than in LCNNECs. Immunohistochemically detected bax, bcl-2 and bak expression was independent of apoptotic index in both tumor types, while there was a statistically significant positive association between mcl-1 expression and apoptotic index in LCNNEC but not in LCNEC. There was a statistically significant association between high apoptotic index and shortened survival in LCLC. However, no association was found between tumor stage and apoptosis. The patients with LCNEC and low bcl-2 protein expression had a significantly shorter survival time than those with high bcl-2 indices. There was also a clear association between shortened survival and necrotic LCNNEC. LCLCs show relatively high apoptotic activity, which is associated with shortened survival. The expression of bcl-2, bak and mcl- 1 is associated with neuroendocrine differentiation in LCLC. Finally, our results support some previous reports suggesting that bcl-2 expression in combination with some other markers involved in apoptosis and/or proliferation may be of prognostic value in cases of lung carcinoma with neuroendocrine differentiation.
Apoptosis plays an important role in cancer biology. We investigated the expression of caspases 3 and 8 in malignant mesothelioma and malignant mesothelioma cell lines and putative changes in their ultrastructural expression prior and after exposure to epirubicin. Further studies were conducted to compare these changes to the localization and expression of the bcl-2 group of proteins bcl-X, bax and mcl-1, and Fas-Fas ligand in the same cells. In the histological samples, caspase 3 and 8 immunoreactivity was seen in 27/37 (73%) and 16/37 (43%) of the mesotheliomas. The immunostaining was cytoplasmic diffuse, granular, and occasionally nuclear. All six mesothelioma cell lines expressed caspases 3 and 8 by immunoblotting. After exposure to epirubicin the extent of apoptosis was increased in all cell lines investigated, being weakest in the most resistant M38K cell line. Immunoelectron microscopy revealed immunogold labeling for caspases 3 and 8 in the mitochondria with the accumulation of caspase 3 in the apoptotic bodies, while the mitochondrial localization of the bcl-2 proteins appeared to be very stable. Fas receptor could be detected by flow cytometry, whereas the most resistant cell line (M38K) lacked Fas ligand when assessed by RT-PCR. These results suggest the importance of caspase 3 during the apoptotic process of mesothelioma cells and indicate that epirubicin-induced apoptosis is independent of the mitochondrial pathway.
A prospective epidemiological study was conducted to assess the incidence, diagnosis, histology and surgical treatment of lung cancer in northern Finland. The results were compared with those obtained in a similar survey 20 yrs earlier. Most of the patients with a suspected lung tumour were interviewed (72%) and the information was combined with that obtained from the national cancer registry. All pathological specimens were re-evaluated by a pathologist. A total of 602 new lung cancer cases (85% male, 15% female) were diagnosed during the years 1990-1992, the annual incidence per 100,000 being 63 for males and 9.5 for females. The number not reported to the Finnish Cancer Registry was low (
We investigated apoptosis and the expression of bcl-2, mcl-1, bcl-X, and bax in histological sections from 35 malignant mesotheliomas and 21 metastatic adenocarcinomas. Moreover, the expression of bcl-2, mcl-1, bcl-X, and bax were assessed by Western blotting in nonmalignant human mesothelial cells (Met5A) and seven malignant cell lines. The apoptotic index in mesotheliomas was 1.07+/-1.14%. Patients with mesotheliomas showing a high apoptotic index (> or =0.75%) had a worse prognosis (P = 0.008). bcl-2 positivity was observed in only seven cases, but bcl-X, mcl-1, and bax positivity was seen in all of them. In immunoblotting experiments, all mesothelioma cell lines were negative for bcl-2 but positive for bcl-X, mcl-1, and bax. The apoptotic index in bcl-2-negative mesotheliomas was 1.25+/-1.24% and in bcl-2-positive ones, 0.47+/-0.42% (P = 0.014). The apoptotic index did not significantly associate with bcl-X, mcl-1, or bax expression (P = 0.19, P = 0.25, and P = 0.46, respectively). No significant difference was observed in apoptosis or expression of bcl-2, bcl-X, or bax between malignant mesotheliomas and metastatic adenocarcinomas. The former, however, showed more often weak mcl-1 immunoreactivity (P = 0.01). The results show that the extent of apoptosis may influence patient prognosis. bcl-2 is inversely associated with the apoptotic index but is relatively infrequently expressed in malignant mesotheliomas. Widespread expression of bcl-X, mcl-1, and bax suggests that these proteins may also take part in apoptosis regulation in mesotheliomas.
In this study we investigated the immunohistochemical expression of caspases 3, 6 and 8 in 85 malignant non-Hodgkin's lymphomas and in 4 hyperplastic lymph nodes. The extent of apoptosis and the immunohistochemical expression of bcl-2 and bax was also studied. Caspase 3 immunoreactivity was seen in 84/85 (99%), caspase 6 in 46/85 (54%), and caspase 8 in 66/85 (78%) lymphomas. The immunoreactivity for caspase 3 was diffuse cytoplasmic while antibodies to caspase 6 and 8 showed granular and fragmented, sometimes also nuclear immunopositivity. High-grade non-Hodgkin's lymphomas expressed strong caspase 6 and 8 immunoreactivity significantly more often than low-grade lymphomas (p = 0.016 and p = 0.0002, respectively). Strong caspase 3 immunoreactivity was also seen more often in high-grade lymphomas, but the association did not reach statistical significance (p = 0.14). There was a strong association between the expression of caspase 3 and 6 (p = 0.032), caspase 3 and 8 (p = 0.042), and especially between caspase 6 and 8 (p =
The purpose of this study was to investigate apoptosis, proliferation, and the expression of apoptosis-influencing proteins bcl-2 and bax and estrogen and progesterone receptors during breast carcinoma progression. The material consisted of 53 paired breast carcinoma samples representing primary and recurrent tumors and 24 control samples. The recurrent sample was located either in the breast scar tissue or at a distant metastatic site. Apoptosis was detected both morphologically and by 3' end labeling of fragmented DNA. Cell proliferation was evaluated immunohistochemically by the MIB index. The expressions of bcl-2, bax, and estrogen and progesterone receptors were studied immunohistochemically. There was a significant increase in the extent of apoptosis and proliferation in recurrent tumors compared to the primary lesions (P = 0.015 and P = 0.038, respectively). In primary tumors with an apoptotic index of >0.50%, the survival of the patients was significantly shorter (P = 0.015). In cases with a significant increase in apoptosis or proliferation in the recurrent tumor, the survival of the patients was significantly shorter (P = 0.009 and P = 0.003, respectively). Of the variables analyzed, bcl-2 expression and a positive estrogen receptor status were significantly associated with a low extent of apoptosis (P = 0.010 and P = 0.042, respectively). Their changes were parallel to the changes in apoptosis during tumor progression, although the associations did not reach statistical significance. The results show that increased apoptosis is associated with a worse prognosis in breast carcinoma. A significant increase in apoptosis in recurrent breast carcinoma lesions predicts a worse clinical outcome.
In this study we investigated apoptosis and the expression of caspases 3, 6 and 8 and bcl-2, mcl-1 and bax in 39 gallbladder carcinomas and 7 epithelial dysplasias. The average apoptotic index was 0.68 +/- 0.91%. The extent of apoptosis was higher in grade II-III than grade I tumours or epithelial dysplasias (p = 0.003). Also, tumours invading beyond serosa or into other organs (T3-T4) had a higher apoptotic index than other tumours (p = 0.05). Caspase 3 expression was found in 37 (95%) and caspase 6 and 8 expression each in 30 (77%) carcinomas. Their expression associated with each other and tended to increase along with the progression of the lesions. Bcl-2 expression was found in only 4 (10%) tumours. In contrast, mcl-1 positivity was found in 34 (87%) and bax positivity in all cases. The results show that apoptosis is increased along with progression of the neoplastic lesions of the gallbladder epithelium. Caspases 3, 6 and 8 are strongly expressed in gallbladder carcinomas suggesting that they contribute to the increased apoptosis observed in them. Of the bcl-2 family proteins, bcl-2 was expressed infrequently suggesting that it does not play any significant role in apoptosis inhibition in gallbladder tumours.
The present study was undertaken to analyse the extent of apoptosis in operated small cell lung carcinoma (SCLC) by using in situ labelling of the oligonucleosomal DNA fragments by terminal transferase. The extent of apoptosis was compared with the cell proliferation activity, as determined by Ki-67 immunohistochemistry; with the volume density of necrosis (per cent), as determined by the morphometric point counting method; and with the occurrence of immunohistochemically detectable p53 and bcl-2 proteins. By in situ labelling, remarkably high apoptotic indices (from 0.08 to 8.10 per cent) were seen in SCLC. A high percentage of SCLSs also showed an exceptionally high proliferation activity. Aberrant accumulation of p53 protein was seen in 37.5 per cent and bel-2 overexpression in 50 per cent of SCLCs. Necrosis was seen in 82.5 per cent of SCLCs. The extent of apoptosis was inversely related to the extent of tumour necrosis (P = 0.05) and to p53 protein accumulation (P = 0.008). A positive association was found between the extent of apoptosis and bel-2 immunoreactivity (P = 0.02). The apoptotic indices (per cent) correlated with the age (P
AIMS: We investigated the extent of apoptosis in 55 benign and malignant salivary gland tumours and its association with the immunohistochemical expression of bcl-2 and bax. METHODS AND RESULTS: Apoptosis was detected in histological sections by the 3'-end DNA labelling method. bcl-2 and bax protein expression was determined by immunohistochemistry. The frequency of apoptosis was clearly higher in malignant than in benign tumours. In pleomorphic adenomas and Warthin's tumours the average apoptotic index was 0.01% (range 0.00-0.07%) while in the malignant salivary gland tumours it was 0.42% (range 0.00-1.75%). Immunohistochemical bcl-2 expression was observed in all pleomorphic adenomas and Warthin's tumours and in most cases the expression was strong. In malignant tumours, 9/25 cases showed no expression and in the rest of the cases, apart from adenoid cystic carcinomas, the bcl-2 expression was often weak. There were significantly more cases with no or weak bcl-2 positivity in malignant than in benign salivary gland tumours (P = 0.001). There was a statistically significant association between a weak bcl-2 expression and a high frequency of apoptosis (P = 0.02). In contrast to bcl-2, strong bax expression was found in both benign and malignant tumours and was not associated with the frequency of apoptosis. CONCLUSIONS: The low bcl-2 expression in malignant tumours suggests that down-regulation of its expression might contribute to their higher frequency of apoptosis.