Biomedical subjects

L Chyczewski

Publications and source records attributed to L Chyczewski.

At least 37 records · Page 2Linked to original sources

PubMed2001

Morphological aspects of carcinogenesis in the lung.

The origins of the various histological types of primary lung cancer are not well understood. Numerous recent studies have indicated that lung cancer is not a result of a sudden transforming event in the bronchial and alveolar epithelium and in the neuroendocrine cells, but a multistep process in which a sequence of morphological and genetic changes is occurring. New modern technical approaches like fluorescence bronchoscopy techniques and microdissection, provide facilities to obtain valuable specimens for morphological and genetic verification of the sequentional changes in lung cancerogenesis. With their help, cells with morphologically recognized changes thought to be preneoplastic, may be removed and prepared for molecular and genetic studies. Therefore, the knowledge of the morphological aspects of lung preneoplastic lesions is crucial to make progress in molecular studies of lung carcinogenesis. Presently the knowledge about the sequence of molecular events in the lung carcinogenesis and their relationship to morphology is not perfect. In this review we will describe morphological aspects of various preneoplastic lesions occurring in the bronchial and bronchiolo-alveolar compartments including neuroendocrine cells.

Cell Differentiation↗

PubMed2001

Types and localisation of p53 gene mutations: a report on 332 non-small cell lung cancer patients.

Mutations of p53 suppressor gene are among the most common molecular abnormalities in human malignancies. We demonstrated earlier significant differences in mutational profiles between NSCLC patients from Poland and Spain. These differences were most probably related to ethnic and/or geographical factors. In the present study we analyzed the types and location of p53 gene mutations in a large group of 332 operated NSCLC patients from two institutions in Northern Poland. Within the last decades this region has been characterized by the highest incidence of lung cancer in Poland. We used both frozen and paraffin-embedded tumor samples and the screened region included exons from 5 to 8. A total of 96 samples (29%) were positive for p53 gene mutation. The proportion of mutations in particular exons was as follows: exon 5-33%, exon 6-22%, exon 7-16%, and exon 8-29%. Three 'hot spots' were located in codons 176,245 and 248. Evolutionary conserved domains were much more frequently affected than the regions outside domains. The majority of mutations (73%) were missense type, followed by null and silent mutations (21 and 6%, respectively). In all six silent mutations substituted was the third base in codon. There were no major differences in the types and locations of mutations between patients from the two institutions. This homogeneity, together with our earlier findings, may confirm the impact of ethnic and geographical factors on the mutational profile of p53 gene in NSCLC.

Aged↗

PubMed2001

Prognostic molecular markers in non-small cell lung cancer.

Although TNM stage is the most significant prognostic parameter in lung cancer, additional parameters are required for explaining variability of survival. Hence molecular alterations in lung cancer have been extensively studied. Most prominent among them are alterations in the p53-p21 pathway, controlling the G1/S transition. They are the most commonly observed aberrations in non-small cell lung cancer (NSCLC). The results of p53 mutations on an individual patient's changes for survival are rather controversial. In a recent study however, after analyzing p53 abnormalities both by direct sequencing and immunohistochemistry together with evaluation of bcl-2 protein expression, we have found that p53 alterations were significantly associated with poor overall survival. Recently, a more sensitive yeast functional assay for altered p53 protein has been developed, with about 70% positivity in NSCLC patients and a correlation with shortened survival. The clinical significance of p21WAF1, the protein encoded by the target gene of p53 transcription, is still controversial; however expression has been associated with favorable prognosis in squamous cell carcinoma type. The 'Rb pathway' involving two oncogenes (cyclins D and E) and two tumor suppressor genes (Rb and p16) represents another major source of molecular alterations in lung cancer. Loss of Rb does not seem to significantly influence prognosis, white loss of p16 has been show repeatedly to be a factor for poor survival. Hypermethylation of the promoter region has been proposed as an alternative mechanism for inactivation of the p16 gene. The relation between cyclin D and E expression and prognosis, still is matter of controversy. Ras mutations are reported especially in adenocarcinoma; considered alone they bear no clear relation with prognosis, in opposition when considering them together with other molecular alterations. As a conclusion, a variety of molecular markers have been implicated in the prognosis of NSCLC. However, conflicting results were reported in the literature. Thus further investigations will be required, especially the use of newer molecular assays and the development of appropriate markers or panels of molecular markers.

Biomarkers, Tumor↗

PubMed2001

Expression of vascular endothelial growth factor (VEGF) in non-small cell lung cancer (NSCLC): association with p53 gene mutation and prognosis.

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine that increases microvascular permeability and directly stimulates endothelial cell growth and angiogenesis. Recent evidence suggests that the genetic regulation of angiogenesis is also of crucial importance and that oncogenes and tumor suppressor genes can regulate it. The aim of this study was to determine the prognostic value of VEGF and its possible association with p53-gene mutation in 89 stage I-IIIa surgically treated NSCLC patients. DNA sequencing of the p53 gene (exons 5-8) showed 40 mutations (45%). Among the 89 NSCLC patients, immunoreactivity for VEGF was weakly, moderately and strongly positive in 35 (39%),36 (40%) and 18 (20%) cases, respectively. A strong, statistically significant association was found between the presence of a p53 gene mutation and expression of VEGF (P<0.001). The positive result of the p53 mutation increased the odds of observing a higher level of VEGF expression approximately 9.5 times (95% confidence interval: [3.44,25.89]). In the univariate analysis of survival, increasing levels of VEGF expression were associated with poor prognosis (P<0.001 for trend). In the multivariate analysis, after adjusting for the presence of a p53-gene mutation, gender, TNM stage and histological type, the prognostic effect of VEGF expression level was marginally non-significant (P=0.077). When the two-category quantification of the VEGF level was considered (low vs. intermediate/high), a marginally significant (P=0.024), unfavorable effect of intermediate/high levels of VEGF expression, independent of the effect of the presence of a p53-gene mutation, was found. In conclusion, we found that the p53 mutation was closely related to VEGF expression. Additionally, we observed that an intermediate/high expression of VEGF might be a useful indicator of prognosis in NSCLC. This latter conjecture, suggested by an analysis of the data, ought however, to be independently verified in further studies.

Biomarkers, Tumor↗

PubMed2001

The impact of immune responses on lung cancer and the development of new treatment modalities.

OBJECTIVE: This presentation covers predominantly review data in relation with immune responses initiating and accompanying lung carcinogenesis or- on the contrary-contributing to novel therapeutic developments. Occasionally, personal findings will be considered. RESULTS 1 OF IMMUNE DEFICIENCY: It is known for several decades that cancer incidence (several sites) is increased in subjects receiving immunosuppressive therapy, e.g. to avoid transplant rejection, or suffering from AIDS. We have observed that in areas heavily polluted by industrial activities, resulting in immune deficiency, cancer incidence is increased, notably for lung cancer. On the other hand, neoplastic cells are able to escape the host's immune responses by inducing apoptosis of the effector T lymphocytes. Apoptosis in T-cells is triggered by the interaction of the membrane receptor Fas with its normal ligand Fas L, or an activating antibody. Now lung carcinoma cells have been shown to express Fas L, enabling them to destroy cytolytic T cells. RESULTS 2 OF IMMUNE TREATMENT: It is well over a century ago that interest in the immunotherapy of cancer was aroused by the observation of tumour regressions concomitant with bacterial infection, an observation leading to the development of 'Coley's toxin', a mixture of killed bacteria (presently known to act through the presence of TNF-alpha). Since these long-standing empirical attempts, a lasting search for immune control of cancer has been initiated, comprising such different approaches as active non-specific immunotherapy, active specific immunotherapy, approaches based on the use of monoclonal antibodies, as well as those depending on cellular immunity and the development of adoptive immunotherapy, and the use of peptide vaccines. These different approaches will be described and their results presented. CONCLUSION: Present state-of-the-art will be discussed and new pathways for development evoked; better understanding of immune mechanisms is opening new avenues for improved treatment efficacy.

Antibodies, Monoclonal↗

PubMed2001

The preoperative study of mediastinal lymph nodes metastasis in lung cancer by endoscopic ultrasonography (EUS) and helical computed tomography (CT).

OBJECTIVE: Accurate staging of mediastinal lymph nodes in patients with lung cancer is fundamental for their treatment and prognosis. The aim of this study was to compare the value of EUS and CT staging in patients with non-small-cell lung cancer (NSCLC) with postsurgical stage. METHODS: Ninety two patients with NSCLC underwent EUS and CT for preoperative detection of metastases to the mediastinal lymph nodes. EUS examinations were done with the ultrasonic linear array scanning echoendoscope (FG 32 UA, Hitachi/Pentax), CT-Toshiba Exvision GX scanner, with 24-s spiral acquisition, pitch 1:1 (7 mm collimation, 4 mm reconstruction index), during i.v. administration of non-ionic iodinated contrast media. RESULTS: The frequency of mediastinal involvement was 22.7%. The regions most accessible by EUS evaluation were subaortic, subcarinal and paraoesophageal lymph nodes. On a per-patient basis, EUS and CT results were: sensitivity 70.0 and 60.0%, specificity 80.6 and 72.6%, accuracy 77.2 and 68.5%. On a per-sites basis, the sensitivity of EUS evaluation was 78.8%, specificity 89.9%, accuracy 87.7%, comparing with CT-63.6, 84.0, 79.9%, respectively. When the EUS and CT images were analysed in combination, the sensitivity increased to 86.4%. CONCLUSION: We believe that EUS and CT should be used together for preoperative non-invasive staging of mediastinal lymph nodes in patients with NSCLC.

Carcinoma, Non-Small-Cell Lung↗

PubMed2001

Molecular genetic abnormalities in premalignant lung lesions: biological and clinical implications.

Lung cancer is a leading cause of cancer death worldwide; however, despite major advances in cancer treatment during the past two decades, the prognostic outcome of lung cancer patients has improved only minimally. This is largely due to the inadequacy of the traditional screening approach, which detects only well-established overt cancers and fails to identify precursor lesions in premalignant conditions of the bronchial tree. In recent years this situation has fundamentally changed with the identification of molecular abnormalities characteristic of premalignant changes; these concern tumour suppressor genes, loss of heterozygosity at crucial sites and activation of oncogenes. After considering the morphological modifications that occur in premalignant lesions of the bronchial tree, we analyse the alterations occurring in a series of relevant genes: p53 and its functional regulation by MDM2 and p14ARF, p16INK4, p15INK4b, FHIT, as well as LOH at important sites such as 3p, 8p, 9p and 5q. Activation of oncogenes is considered for K-ras, the cyclin D1, the heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1), and finally the c-myc oncogene. The expression of c-myc is influenced strongly by the presence of growth factors (GFs), among which EGF is of prime importance, as well as its receptor coded for by the c-erbB-2 oncogene. Basic knowledge at the molecular level has extremely important clinical implications with regard to early diagnosis, risk assessment and prevention, and therapeutic targets. The novel techniques for early diagnosis and screening of premalignant lung lesions, such as fluorescence bronchoscopy, endobronchial ultrasound, spiral computed tomography combined with precise spatial localization techniques, should basically change the approach to the problems raised by this disease and allow for an increased discovery rate of incipient lesions. Sequential applications will lead to the identification of individuals/populations at high risk, while the availability of accurate 'intermediate end points' will enable the effects of preventive trials to be monitored. Finally, the same molecular abnormalities may serve as 'starting points' for innovative treatments designed to restore the altered functions to normality. Recent developments in our knowledge and understanding of the molecular genetic abnormalities in premalignant lung lesions open an era of hope.

Gene Expression Regulation, Neoplastic↗

PubMed2001

Prognostic significance of p53 and bcl-2 abnormalities in operable nonsmall cell lung cancer.

The association of p53 abnormalities and bcl-2 protein expression with clinical data and prognosis in 102 patients with resected nonsmall cell lung cancer (NSCLC) was investigated. Deoxyribonucleic acid analysis of exons 5-8 of the p53 gene showed mutations (p53-M) in 47% of resected NSCLC, serum p53 antibodies (p53-Abs) were detected in 25%, p53 protein overexpression (p53-PE) in 54%, and bcl-2 protein overexpression (bcl-2-PE) in 48%. A statistically significant association was found between p53-PE, serum p53-Abs and the presence of a p53 gene alteration. No significant associations were found between results of the p53-M, p53-Abs, bcl-2-PE tests and clinicopathological parameters. In the case of the p53-PE test there were significantly fewer positive results for adenocarcinoma than for squamous cell carcinoma and large cell carcinoma. Survival analysis showed that both p53 abnormalities and negative staining for bcl-2, when analysed separately, were associated with poor overall survival. In a multivariate analysis, only the positive result of the p53-M test remained an independent, statistically significant, unfavourable prognostic factor for survival. When the p53 mutation test was removed from the model, positive results of the p53-PE test and the p53-Abs test became statistically significant, unfavourable prognostic factors. To conclude, among p53 and bcl-2 abnormalities, only p53 gene mutations seem to have a strong and independent effect on prognosis. When deoxyribonucleic acid sequence information is not available, p53 protein expression and the presence of p53 antibodies in serum may be used to obtain important prognostic information.

Adenocarcinoma↗

PubMed2001

[Protein P53 in laryngeal cancer--no evidence of prognostic value].

The aim of the study was to verify a relationship between P53 protein expression and prognosis in laryngeal cancer. P53 protein levels were studied by immunohistochemical staining of 80 primary laryngeal SCC. Forty five tumours (56.3%) had a positive staining for P53 protein. There was no correlation between P53 overexpression and disease-free survival. No prognostic significance of P53 protein expression in laryngeal cancer was found.

Adult↗

PubMed2001

[The role of pulmonary mast cells in hemorrhagic shock].

In the course of hemorrhagic shock there are multidirectional organ changes that result in intensified disfunction of important organs as well as multiorgan insufficiency syndrome. The syndrome is a cause of high posthemorrhagic mortality. The general inflammatory reaction of intestine--liver--lungs--immunological system increases in a cascadical way and has a significant role in the pathogenesis of the syndrome. Mast cells activated as a result of ischemia and reprefusion participate in this phenomenon.

Animals↗

PubMed2001

Detection of human papillomavirus in non-small cell lung carcinoma by polymerase chain reaction.

Human papillomavirus (HPV) infection is one of the risk factors contributing to the pathogenesis of lung cancer. The aim of the study was to determine the presence of HPV in non-small cell carcinomas of the lung. The study included 40 tumors: 22 squamous cell carcinomas, 13 adenocarcinomas and 5 large cell carcinomas. HPV was found in 4 cases (10%). High risk HPV was present in 3 tumors: in one squamous cell carcinoma, one large cell carcinoma and one adenocarcinoma, while low risk HPV was detected in one adenocarcinoma.

Carcinoma, Non-Small-Cell Lung↗

PubMed2001

Detection of P53 abnormalities in non-small cell lung cancer by yeast functional assay.

We assessed the status of P53 in 32 surgically treated non-small cell lung cancers (NSCLC) by using yeast functional assay. For functional assay, total RNA extracted from fresh-frozen specimens was reverse transcribed and P53 cDNAs were PCR-amplified using Pfu DNA polymerase (Stratagene). The transcriptional competence of the P53 cDNA was then tested in a yeast reporter strain. 20 of the 32 (69%) NSCLC patients contained mutant P53 in the yeast functional assay with the higher frequency in squamous cell carcinoma (14/17, 82%) than in adenocarcinoma (5/10, 50%) and large cell carcinoma (3/5, 60%) (p<0.01, chi2 test). No significant difference was observed with respect to the TNM. Preliminary survival analysis showed that patients scoring positive for the yeast test had shorter disease-free survival (median = 10 months) than those that scored negative (median > 21 months). Our results suggest that yeast functional assay is not only an improved method to examine the status of P53, but might hopefully improve understanding of the role of mutant P53 in the clinical evaluation of NSCLC.

Carcinoma, Non-Small-Cell Lung↗

PubMed2001

Morphological and molecular aspects of cancerogenesis in the lung.

Morphology and some molecular aspects of hyperplastic (bronchial basal cell hyperplasia and alveolar cell hyperplasia), metaplastic (squamous metaplasia), preneoplastic and early neoplastic (dysplasia in squamous metaplasia, cancer in situ and atypical alveolar cell hyperplasia) changes were studied in 180 lungs resected due to non-small cell lung cancer: 106 cases (58.9%) of squamous cell carcinoma, 42 (23.3%) of adenocarcinoma and 32 (17.8%) of large cell carcinoma. P53 protein and PCNA expressions were detected immunohistochemically (using formalin-fixed, paraffin-embedded sections). DNA extracted from the microdissected P53-positive cells was analysed for point mutations in the P53 gene. No P53 immunostaining was observed in normal mucosa, hyperplasia of basal cells, squamous metaplasia without and with minor and moderate dysplasia of bronchial mucosa as well as alveolar cell hyperplasia. Overexpression of P53 protein occurred in 3 out of 12 (25%) cases of severe bronchial dysplasia, 5 out of 11 (45.5%) cases of intraepithelial carcinoma and 6 out of 45 (13.3%) cases of alveolar cell hyperplasia. Using direct sequencing, mutations in the P53 gene were detected in 11 out of 14 (87%) P53-immunopositive samples, including all severe dysplasias, all carcinomas in situ and 3 of 6 alveolar cell hyperplasias. A significant association was observed between PCNA expression and preinvasive as well as invasive lesions. The data clearly show that lung resected due to primary cancer ought to be treated as "field cancerization" in which one can find early morphologic events of multi-step cancerogenesis. P53 protein alterations and P53 gene mutations can occur before invasion and its frequency depends on the degree of dysplasia.

Carcinoma, Non-Small-Cell Lung↗

PubMed2001

Expression of P53 protein in primary uveal melanoma.

Malignant melanomas are the commonest intraocular tumours. The aim of the present study was the immunohistochemical analysis of P53 protein expression in 39 primary ocular melanomas treated surgically in the years 1983-1997. Expression of P53 was estimated semiquantitatively with the use of a light microscope at a magnification of x 400. At least 200 neoplastic cells per sample were analysed. The expression of P53 in 3% of melanoma cells was considered the threshold of positive reaction. The results were subjected to statistical analysis with exact Fischer's test. No statistically significant correlations were found between P53 expression and anatomoclinical properties of tumours, although increased P53 expression was observed in epithelioid-cellular melanomas and in tumours growing in women. A lack of statistically significant relationship between P53 protein level and the parameters examined, and morphological specificity of ocular melanomas hindering immunohistochemical analysis, indicate the necessity for studies on a wider group of tumours or/and use of molecular biology techniques to establish possible relations between P53 gene mutation and ocular melanoma biology.

Adult↗

PubMed2001

Preliminary evaluation of influence of gemcitabine (Gemzar) on proliferation and neuroendocrine activity of human TT cell line: immunocytochemical investigations.

The choice treatment of medullary thyroid carcinoma (MTC) is total thyroidectomy. It is difficult to evaluate effectiveness of chemotherapy due to the rare incidence of MTC. Gemcitabine is a new drug of antimetabolite nucleoside group used in treatment of cancers since 1996. The aim of this study was to evaluate the influence of gemcitabine on proliferation and neuroendocrine activity of human TT cell line derived from MTC. The cells were exposed to gemcitabine in the concentration of 10, 25 and 50 microg/ml for 24 hours. Immunocytochemical examinations were carried out by the method of avidin-biotin peroxidase complex (ABC) according to Hsu et al. to detect calcitonin, chromogranin A, synaptophysin and neuron-specific enolase in TT cells. A concentration-dependent inhibitory influence of gemcitabine on proliferative activity of TT cells was observed. It was also shown that the immunostaining was reduced, especially in case of neuron-specific enolase. Only the reaction detecting calcitonin was enhanced in persistin

Antimetabolites, Antineoplastic↗

PubMed2001

Preliminary immunohistochemical investigations of human thyroid C cells in the simple and hyperactive nodular goitre.

The aim of this study was to carry out histomorphological and immunohistochemical analysis of thyroid C cells in 30 patients with simple goitre and hyperactive goitre including Graves-Basedow (G-B) disease, treated surgically. Four tissue samples were always taken from the same internal parts of the gland where the number of C cells in physiological conditions was the highest. C cells were detected in paraffin sections after impregnation with silver salt (Grimelius method) or immunohistochemically, with antibodies against calcitonin, synaptophysin, chromogranin A and neuron-specific enolase. Distinctly less numerous C cells were found in simple and hyperactive goitre than in normal thyroid parenchyma. The majority of C cells showed weak intensity of the examined immunohistochemical reactions. C cells were not observed at all in the texture of nodules well separated by the connective tissue. Proliferative changes concerned only follicular cells.

Adult↗

PubMed2001

Strong association between P53 protein accumulation, serum antibodies and gene mutation in non-small cell lung cancer.

DNA sequencing is the gold-standard method, but it is not feasible on a routine clinical basis. Immunohistochemistry is the most widely used method for assessing P53 alterations in human cancers. It can be performed during routine analysis, but some mutations may not lead to P53 protein accumulation, or P53 overexpression may be detected in the absence of mutations of the P53 gene. Recent studies have demonstrated the appearance of P53 antibodies in the serum of patients with lung cancer, probably due to the accumulation of mutant P53 protein in tumor cells. Using a logistic regression model applied to data for 102 non-small cell lung cancer (NSCLC) patients, we show a strong association between results of P53 mutation (P53-M) test, TNM stage and results of anti-P53 antibody in serum (P53-Abs) and P53 protein expression (P53-PE) tests. According to that model, we propose a procedure allowing for prediction of result of P53-M test. The percentage of correct predictions for independent data of 15 NSCLC patients was 80%. We conclude that in the absence of P53-M test result, a reasonably precise prediction of the test can be obtained using TNM stage and results of P53-Abs and P53-PE tests. The prediction can in turn be used to evaluate prognosis of NSCLC patients.

Antibodies, Neoplasm↗

PubMed2001

New molecular approaches to lung cancer: biological and clinical implications of P53, P16 and K-RAS studies.

The most common genetic changes associated with lung cancer involve abnormalities of the genes that regulate the cell cycle. Molecular networking of P53 and P16 tumor suppressor genes and K-RAS oncogene exerts a crucial impact on cell cycle regulation and appears to be of major clinical significance for lung cancer evaluation. The present review article summarizes evaluations of P53, P16 and K-RAS in lung cancer with particular focus on biological and clinical implications, as well as on new molecular approaches to the study of these genes: P53 by yeast functional assay, P16 by methylation specific PCR (MSP) and K-RAS by enriched PCR technique.

Animals↗