PubMed Health⌕ Search

Biomedical subjects

K Mattson

Publications and source records attributed to K Mattson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Phase II study of weekly gemcitabine in advanced non-small cell lung cancer.

New active agents are needed to develop effective systemic therapy against Stage IIIB-IV non-small cell lung cancer (NSCLC). The aim of the present study was to assess the efficacy and toxicity of gemcitabine, a novel nucleoside analogue with significant preclinical activity, as a single-agent therapy. Forty-three patients with previously untreated Stage IIIB-IV NSCLC were included. Gemcitabine was administered intravenously over 30 min on Days 1, 8 and 15 of each 28-day cycle at a dose of 1250 mg m-2. Thirty-seven patients were evaluable for response. There were seven partial responses giving an overall response rate of 19% (95% confidence interval 8-35%). Median duration of response was 6 months. One-year survival and median survival for all patients were 33% and 8 months, respectively. Toxicity of the treatment was mild. World Health Organization (WHO) Grade 3-4 leukopenia was detected in 11% of the patients. Mild (WHO Grade 1-2) nausea was the most frequent subjective side-effect with a rate of 82%. Mild rash and peripheral oedema were typical side-effects of gemcitabine with rates of 19 and 9%, respectively. In conclusion, single-agent gemcitabine is an active and well-tolerated treatment for Stage IIIB-IV NSCLC patients.

Adult↗
PubMed1997

Etoposide in malignant pleural mesothelioma: two phase II trials of the EORTC Lung Cancer Cooperative Group.

Intravenous and oral etoposide (VP 16-213) were tested in two sequential phase II trials in chemotherapy-naive patients with malignant pleural mesothelioma. In the first trial, etoposide was given intravenously (i.v.) at a dose of 150 mg/m2 on days 1, 3 and 5 every 3 weeks. The second trial investigated a daily oral dose of 100 mg for 21 days followed by a 2-week treatment-free period, and then recycling. In both trials, the treatment was given until disease progression, intolerable toxicity or patient refusal. In the i.v. trial, 49 patients were included, 2 patients were ineligible. The oral trial recruited 45 patients, 4 patients were not eligible. In both trials, the main side-effects were moderate leucopenia, alopecia, nausea and vomiting. Two partial responses (4%) and three partial responses (7%) were reported in the i.v. and oral trials, respectively. The median survival was 29 weeks and 38 weeks in the i.v. and oral trials, respectively. In conclusion, further investigation of etoposide in malignant mesothelioma is not recommended.

Administration, Oral↗
PubMed1997

Single-agent gemcitabine versus cisplatin-etoposide: early results of a randomised phase II study in locally advanced or metastatic non-small-cell lung cancer.

BACKGROUND: This randomised study was designed to determine the response rate survival and toxicity of single-agent gemcitabine and cisplatin-etoposide in chemo-naïve patients with locally advanced or metastatic non-small-cell lung cancer. PATIENTS AND METHODS: Gemcitabine 1,000 mg/m2 was given as a 30 min intravenous infusion on days 1, 8, 15 of a 28-day cycle, cisplatin 100 mg/m2 on day 1, and etoposide 100 mg/m2 on days 1 (following cisplatin), 2 and 3. Major eligibility criteria included histologically confirmed non-small-cell lung cancer, measurable disease, Zubrod PS 0-2; no prior chemotherapy, no prior radiation of the measured lesion, and no CNS metastases. RESULTS: 146 patients were enrolled, 71 patients on gemcitabine and 75 patients on cisplatin-etoposide. Patient characteristics were well matched across both arms. Sixty-six gemcitabine patients and 72 cisplatin-etoposide patients were evaluable. Partial responses were seen in 12 gemcitabine patients (18.2%; 95% CI: 9.8-30) and 11 cisplatin-etoposide patients (15.3%; 95% CI: 7.9-25.7). Early indications show no statistical differences between the two treatments with respect to time to disease progression or survival. Haematological and laboratory toxicity were moderate and manageable. However, hospitalisation because of neutropenic fever was required for 6 (8%) cisplatin-etoposide patients but not for any gemcitabine patients. Non-haematological toxicity was more pronounced with significant differences in nausea and vomiting (grade 3 and 4: 11% gemcitabine vs. 29% cisplatin-etoposide; despite the allowance for 5-HT3 antiemetics during the first cycle of cisplatin-etoposide), and alopecia (grade 3 and 4:3% gemcitabine vs. 62% cisplatin-etoposide). CONCLUSIONS: In this randomised study, single-agent gemcitabine was at least as active but better tolerated than the combination cisplatin-etoposide.

Adult↗
PubMed1997

Recurrent DNA copy number changes in 1q, 4q, 6q, 9p, 13q, 14q and 22q detected by comparative genomic hybridization in malignant mesothelioma.

Comparative genomic hybridization (CGH) analyses were performed on 27 human pleural mesothelioma tumour specimens, consisting of 18 frozen tumours and nine paraffin-embedded tumours, to screen for gains and losses of DNA sequences. Copy number changes were detected in 15 of the 27 specimens with a range from one to eight per specimen. On average, more losses than gains of genetic material were observed. The loss of DNA sequences occurred most commonly in the short arm of chromosome 9 (p21-pter), in 60% of the abnormal specimens. Other losses among the abnormal specimens were frequently detected in the long arms of chromosomes 4 (q31.1-qter, 20%), 6 (q22-q24, 33%), 13 (33%),14 (q24-qter, 33%) and 22 (q13, 20%). A gain in DNA sequences was found in the long arm of chromosome 1 (cen-qter) in 33% of the abnormal specimens. Our analysis is the first genome-wide screening for gains and losses of DNA sequences using comparative genomic hybridization in malignant pleural mesothelioma tumours. The recurrent DNA sequence changes detected in this study suggest that the corresponding chromosomal areas most probably contain genes important for the initiation and progression of mesothelioma.

Adult↗
PubMed1997

Interferon maintenance therapy for small cell lung cancer: improvement in long-term survival.

Two hundred thirty-seven patients with small cell lung cancer (SCLC), who had responded to induction chemotherapy and radiotherapy, were randomly assigned to receive low-dose natural interferon-alpha (nIFN alpha) for 6 months; or 6 cycles of maintenance chemotherapy (CAP); or no maintenance therapy (control group). Although there was no difference in median survival between the groups, there was a significant difference (p = 0.04) in the long-term survival of patients with limited disease, in favour of nIFN alpha maintenance therapy. This finding is now confirmed by a further analysis of the most recent data. Ten percent of patients in the IFN group survived for five years or more, but the 5-year-survival rate in the CAP and control groups was only two percent. All long-term survivors had good performance status. The majority had limited disease and had achieved a complete response to the induction therapy. These results suggest that interferon-alpha improves the long-term survival of SCLC patients for whom other prognostic factors are favorable.

Adult↗
PubMed1997

Altered fractionation of hemithorax irradiation for pleural mesothelioma and failure patterns after treatment.

Malignant pleural mesothelioma is a rare malignancy with a bleak prognosis. The role of radiotherapy has not yet been clarified. Our aim was to study the effect of altered fractionation on mesothelioma. We have treated 57 patients, 41 males and 16 females, with hemithorax irradiation with six different fractionation schedules. All the patients have been included in a combined modality program consisting of surgery followed by chemotherapy and finally by hemithorax irradiation. The radiotherapy schedules used were: I. Conventional fractionation of 20 Gy in 10 fractions over 12 days. II. Split-course radiotherapy 55 Gy in 25 fractions of 2.2 Gy over 7 weeks (a two weeks rest halfways) followed by a boost dose of 15 Gy over 8 days to the major tumour area. III. Hyperfractionation of 70 Gy over 7 weeks, 1.25 Gy BID with a 6-h interval and a 10-day rest halfways. IV. Combined hyperfractionation and hypofractionation, 35 Gy hyperfractionation in 28 fractions (1.25 Gy BID with a 6-h interval) over three weeks followed by 36 Gy hypofractionation 9 fractions of 4 Gy given every other day over 3 weeks to the major tumour areas only. V. Hypofractionation of 38.5 Gy over 15 days (9 x 3.5 Gy). VI. Combined conventional radiotherapy and hypofractionation with 20 Gy given conventionally in 10 fractions followed by 10 fractions of 3 Gy over two weeks, overall time 4 weeks. The 2-year survival rate of all patients was 21% and the 5-year survival rate 9%. Two patients are still alive more than 6 and 9 years after radiotherapy. Progression occurred after surgery in four patients, during and after chemotherapy in 22 patients and after completed radiotherapy in 29 patients. The pattern of progression was similar in each treatment group.

Adult↗
PubMed1997

Trends in mesothelioma incidence and occupational mesotheliomas in Finland in 1960-1995.

OBJECTIVES: The study analyzed the recent trend in the incidence of mesothelioma in Finland and evaluated the coverage of reporting work-related mesothelioma. METHODS: The incidence of mesothelioma in 1960-1995 was retrieved from the Finnish Cancer Registry, and the number of asbestos-associated work-related mesotheliomas were taken from the Finnish Register of Occupational Diseases. RESULTS: The annual number of mesotheliomas increased rapidly in 1975-1990. In the 1990s, the age-adjusted incidence remained relatively stable for Finnish men. The annual number of cases still increased among men over 65 years of age, but decreased slightly among men under 55 years of age and among women. About 35 annual cases were diagnosed among men and 10-15 among women in the mid-1990s. The reporting of work-related mesotheliomas improved during the Finnish asbestos program in 1987-1992. In 1993-1995 about 30 annual cases (ie, about 90% of all pleural and 50% of the peritoneal mesotheliomas in men) were reported to be work-related. CONCLUSIONS: The increasing trend in the incidence of mesothelioma in Finland has slowed down in the 1990s, and the maximum of asbestos-related cases in the early 2000s will probably be clearly less than the 100 annual cases estimated in the early 1990s. If the observed trend continues up to 2010, about 40-50 cases among men and 10-20 among women will then be diagnosed annually. Altogether 40-50 of these cases would be related to occupational asbestos exposure.

Aged↗
PubMed1997

A randomized study of gemcitabine monotherapy versus etoposide/cisplatin in the treatment of locally advanced or metastatic non-small cell lung cancer.

This randomized, multinational, multicenter study was designed to determine the response rate of gemcitabine monotherapy and cisplatin/etoposide combination therapy in chemotherapy-naive patients with advanced, recurrent, and/or metastatic non-small cell lung cancer (stage IIIA [if inoperable], IIIB, or IV). One group of patients received gemcitabine 1,000 mg/m2 intravenously once a week for 3 weeks (days 1, 8, and 15) followed by a 1-week rest period. The second group received cisplatin 100 mg/m2 intravenously on day 1 of each 28-day cycle in combination with etoposide 100 mg/m2, administered on days 1, 2, and 3 following the cisplatin infusion. Each patient was allowed to remain on study up to a maximum of six cycles. The planned interim analysis was based on the 117 patients in the study, 116 of whom were randomized up until November 20, 1995. The efficacy analysis was performed on the 107 patients who had data from a minimum of two cycles, whereas the safety analysis was based on data from all 116 randomized patients. In the gemcitabine arm there were 10 of 52 (19%) partial responders; in the cisplatin/etoposide arm there were four (7%) of 54 partial responders. There was a statistically significant difference in the response rates between the two arms, with a 95% confidence interval of 0.6% to 32.1% (P = .040). The median time to progressive disease was 4.2 months for gemcitabine patients and 3.7 months for cisplatin/etoposide patients. There was significantly more alopecia and nausea and vomiting in the cisplatin/etoposide arm compared with the gemcitabine arm, as well as two cases of neutropenic sepsis in the cisplatin/etoposide arm. These data indicate that single-agent gemcitabine is at least as effective as the combination of cisplatin/etoposide in the treatment of advanced non-small cell lung cancer and has an improved safety profile.

Adult↗
PubMed1997

[A phase II multicenter study of gemcitabine in non small cell lung cancers].

Gemcitabine is a novel pyrimidine nucleoside whose activity has been demonstrated on solid tumors. We report here the results of a multicentre phase II trial of gemcitabine in chemonaive patients with inoperable non small cell lung cancer (NSCLC). Gemcitabine was given weekly at a dose of 1,250 mg/m2 administered as a 30 min intravenous infusion, for 3 weeks followed by 1 week of rest (1 cycle). All the 161 patients included were evaluable for toxicity and 151 of them were evaluable for efficacy. The majority of patients had a stage IIIb (31.1%) or stage IV (64.6%) disease; 10.6%, 83.2% and 6.2% of patients had a WHO performance status (PS) 0, 1, and 2, respectively. Adenocarcinoma accounted for 52.2% of cases and squamous cell carcinoma for 43.5% of cases. Three complete responses and 30 partial responses gave an objective response (OR) rate of 21.8% (95% confidence interval; 15.5-29.3%). All responses were validated by an independent Oncology Review Board. Median duration of response was 7.6 months. Median time to progression was 4.6 months (3.3 months in non responders and 7.6 months in responders). Median survival was 7.3 months in non responders and 13.4 months in responders (p < 0.001), which gave an overall median survival of 8.9 months (95% CI: 0.1-21.9 months) in the entire study population. An improvement of symptoms and personal state was also observed. Treatment was well tolerated. Neutropenia was the only dose limiting toxicity. WHO grade 3 or 4 neutropenia occurred in 19.6% and 5.7% of patients, respectively. With a 21.8% OR rate, this multicentre study confirms the activity of gemcitabine as a single agent in patients with inoperable NSCLC. Its good tolerance and original mode of action make gemcitabine a drug of choice in the therapeutic strategy of these tumors.

Adult↗
PubMed1997

Combination treatment with docetaxel (Taxotere) and platinum compounds for non-small cell lung cancer.

There is a strong rationale for combining docetaxel (Taxotere; Rhône-Poulenc Rorer, Antony, France) and platinum compounds for use in the treatment of non-small cell lung cancer (NSCLC). The compounds are active as single agents and have no overlapping toxicity profiles. The first dose-finding study reported a response rate of 46%, and recommended doses of 75 mg/m2 for docetaxel and 75 to 100 mg/m2 for cisplatin, given concomitantly every 3 weeks. Three other studies confirmed a response rate of 33% to 48% in previously untreated patients. Dose-limiting but rapidly reversible neutropenia was observed. A European trial has investigated the use of alternating cycles of docetaxel 100 mg/m2 and cisplatin 120 mg/m2 in patients with previously untreated metastatic or nonresectable NSCLC. Preliminary results indicate that the overall response rate (33% of 39 evaluable patients) is similar to that achieved with docetaxel alone. A second trial is investigating alternating therapy using docetaxel 100 mg/m2 and a combination of cisplatin 100 mg/m2 and vinorelbine 30 mg/m2. Response rates are higher (49%) and toxicities, especially hematologic toxicities, are lower than in the first study. A third trial is investigating sequential treatment using docetaxel 100 mg/m2, cisplatin 120 mg/m2, and vindesine 3 mg/m2. Preliminary results indicate a response rate of 30% among 25 patients enrolled thus far. Compared with monotherapy, docetaxel/platinum combinations appear to offer the potential for improved response rates in patients with NSCLC. The use of alternating schedules offers the further possible advantage of improving tolerability while retaining effective doses. Further studies are in progress or planned to elucidate optimal doses and schedules.

Antineoplastic Agents, Phytogenic↗
PubMed1996

Glutathione S-transferase and N-acetyltransferase genotypes and asbestos-associated pulmonary disorders.

BACKGROUND: Humans vary in their ability to metabolize endogenous and exogenous compounds. Glutathione S-transferases (GSTs) and N-acetyltransferases (NATs) are enzymes involved in the detoxification of hazardous agents. The GSTM1 and GSTT1 genes exhibit null (i.e., deletion) polymorphisms; in specific individuals, homozygous deletion (i.e., both copies lost) of these genes can be detected. Polymorphism of the NAT2 gene results in slow and fast acetylators of potentially toxic substances. The GSTM1-null and the NAT2 slow-acetylator genotypes have been associated with increased risks for the development of environmentally induced cancers. PURPOSE: We assessed whether homozygous GSTM1-null or GSTT1-null genotypes or the NAT2 slow-acetylator genotype were associated with increased risks for the development of malignant and nonmalignant asbestos-related pulmonary disorders in a cohort of Finnish construction workers. METHODS: The study population consisted of 145 asbestos insulators who were classified as having been exposed to high levels of asbestos; 69 of these individuals had no pulmonary disorders (control subjects), and 76 had either malignant mesothelioma (n = 24) or nonmalignant pulmonary disorders, such as asbestosis and/or pleural plaques (n = 52). Lymphocyte DNA and the polymerase chain reaction were used to determine the GSTM1, GSTT1, and NAT2 genotypes of the study subjects. Odds ratios (ORs) and 95% confidence intervals (CIs) estimating the relative risks of disease associated with specific genotypes were calculated from 2 x 2 tables by use of Fisher's exact method. RESULTS: Risks for the development of asbestos-related pulmonary disorders were not affected significantly by homozygous deletion of the GSTM1 or GSTT1 genes. However, the risk of developing both malignant and nonmalignant pulmonary disorders for individuals with a NAT2 slow-acetylator genotype was more than twice that observed for those with a NAT2 fast-acetylator genotype (OR = 2.3; 95% CI = 1.1-4.7); the risk of developing malignant mesothelioma for NAT2 slow acetylators was increased almost fourfold (OR = 3.8; 95% CI = 1.2-14.3). Individuals who lacked the GSTM1 gene and possessed a NAT2 slow-acetylator genotype had a risk of developing malignant and nonmalignant pulmonary disorders that was approximately fivefold greater than that observed for those who had the GSTM1 gene and a NAT2 fast-acetylator genotype (OR = 5.1; 95% CI = 1.6-17.6); these individuals had a fourfold increased risk of developing nonmalignant pulmonary disorders (OR = 4.1; 95% CI = 1.1-17.2) and an eightfold increased risk of developing malignant mesothelioma (OR = 7.8; 95% CI = 1.4-78.7) when compared with the same reference group. CONCLUSIONS: Individuals with homozygous deletion of the GSTM1 gene and a NAT2 slow-acetylator genotype who are exposed to high levels of asbestos appear to have enhanced susceptibility to asbestos-related pulmonary disorders.

Acetylation↗
PubMed1996

Gains and losses of DNA sequences in malignant mesothelioma by comparative genomic hybridization.

The molecular basis of malignant mesothelioma is poorly known. We examined genetic changes in 11 mesothelioma specimens by comparative genomic hybridization (CGH). Five DNA specimens originated from uncultured tumor tissues and six from cell lines established from the same patients. Findings from the classical karyotypic characterization of both primary tumors and cell lines have been reported previously. In the CGH analyses the most common genetic alterations in the 11 mesothelioma specimens were losses of chromosomal regions in 1p, 8p, 14q, and 22q and gains of 5p, 6p, 8q, 15q, 17q, and 20. The cell lines had on average a much higher total number of genetic changes than the uncultured tumor specimens. Clonal relationship between the cell lines and the uncultured tissue specimens could not usually be demonstrated even though they originated from the same patient. The observed differences may partly be due to high frequency of chromosomal rearrangements, which CGH cannot detect, partly due to contamination of tumor specimens with normal tissue, and partly due to genetic evolution in tumor cell lines.

Chromosome Aberrations↗
PubMed1996

Manganese superoxide dismutase in human pleural mesothelioma cell lines.

Mesothelioma is a malignant pleural or intraperitoneal tumor attributable to asbestos exposure in more than 80% of the cases. Manganese superoxide dismutase (MnSOD), a mitochondrial superoxide radical scavenging enzyme, is low in most tumors but is known to be induced by asbestos fibers and certain cytokines. Induction of MnSOD may be associated in asbestos-related pulmonary diseases in vivo. We investigated here MnSOD specific activity and MnSOD mRNA level using healthy human lung tissue, SV40-transformed human pleural mesothelial cells (Met5A), and six human malignant mesothelioma cell line cells. Total SOD (CuZnSOD + MnSOD) and MnSOD activities were 20.0 +/- 4.8 U/mg protein and 3.2 +/- 1.2 U/mg protein in healthy human lung tissue, and 25.6 +/- 10.7 U/mg and 3.8 +/- 1.0 U/mg in Met5A cells, respectively. In four mesothelioma cell lines MnSOD activity was significantly elevated, the highest activity (30.1 +/- 8.2 U/mg) was almost 10-fold compared to the activity in Met5A cells. The steady state mRNA level of MnSOD was low in Met5A cells and markedly higher in all mesothelioma cell lines roughly in proportion with enzyme activities. Cytotoxicity experiments, which were conducted in four cell lines, indicated that cells containing high MnSOD mRNA level and activity were resistant to the mitochondrial superoxide-producing agent menadione. In conclusion, our results suggest that human mesothelioma may express high levels of MnSOD, which is associated with high oxidant resistance of these cells.

Analysis of Variance↗
PubMed1996

Activity of gemcitabine in patients with non-small cell lung cancer: a multicentre, extended phase II study.

Gemcitabine is a novel nucleoside analogue with activity in solid tumours. This study assessed the objective response rate to gemcitabine given weekly intravenously at a dose of 1250 mg/m2 for 3 weeks followed by 1 week of rest (one cycle) in chemonaive patients with inoperable non-small cell lung cancer (NSCLC). 161 patients with NSCLC were recruited from 10 sites in nine countries. Most patients had stage IIIb (31.3%) or IV (64.6%) disease, and 93.8% had a performance status of 0 or 1 according to the WHO scale. Of 151 evaluable patients, there were 3 complete responses and 30 partial responses lasting at least 4 weeks for an objective response rate of 21.8% (95% CI 15.5-29.3%). All responses were validated by an extramural Oncology Review Board. The mean duration of response was 8.8 months. The mean survival for all patients (16.1% of patients still alive 26 months after last patient started treatment) was 11.5 months. Improvements were also observed in secondary efficacy parameters such as performance status, weight, analgesic requirement, pain, and other disease-related symptoms including cough, dyspnoea, haemoptysis, anorexia, somnolence and hoarseness. Haematological and non-haematological toxicity was mild given the biological activity of gemcitabine. This study confirms gemcitabine as one of the most active agents in NSCLC with the added benefit of a modest toxicity profile and ease of administration on an out-patient basis. Gemcitabine is a suitable candidate for combination chemotherapy in patients with NSCLC.

Adolescent↗
PubMed1996

High levels of MDM2 are not correlated with the presence of wild-type p53 in human malignant mesothelioma cell lines.

Prior analysis of 20 human mesothelioma cell lines for p53 status revealed only two mutations and one p53 null cell line, although p53 expression was detected in most cell lines. In addition, mRNA and protein expression of the retinoblastoma gene product in human mesothelioma cell lines is similar to normal controls. We have tested for p53 induction after exposure to ionising radiation and demonstrate this induction and, to a lesser extent, p21(WAF1) induction, in both normal mesothelial cells and p53-positive mesothelioma cell lines. We postulated that high levels of MDM2 might alter p53 and retinoblastoma tumour-suppressor function in mesothelioma. However, Southern blot analysis for mdm2 indicated that no amplification had occurred in 18 mesothelioma cell lines tested. Steady-state mRNA and protein levels also did not indicate overexpression. These results indicate that high levels of MDM2 are not responsible for inactivating the functions of wild-type p53 or the retinoblastoma gene product during the pathogenesis of malignant mesothelioma.

DNA, Neoplasm↗
PubMed1996

A phase II trial of docetaxel in advanced non-small cell lung cancer.

Twenty-nine patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) were treated with docetaxel. Ten patients had already received chemotherapy, the others had received no chemotherapy. Docetaxel was administrated i.v. over 60 min every 21 days at a dose of 100 mg/m2. Twenty-three patients were evaluable for response. There were no complete responses and eight partial responses. The overall response rate was 35% (28% in the intent to treat analysis). Median duration of response was 43 weeks and median time to progression 12 weeks. Neutropenic infections, neurotoxicity and asthenia were dose-limiting toxicities (6% of 118 cycles). The other main toxicities were asthenia in 48%, skin reactions in 31% and nail changes in 31% of the patients. Single-agent docetaxel appears to be active against both previously treated and untreated advanced NSCLC. Toxicity was acceptable but should be carefully monitored.

Adult↗
PubMed1996

Radiosensitivity of mesothelioma cell lines.

The present study was carried out in order to examine the radiosensitivity of malignant pleural mesothelioma cell lines. Cell kinetics, radiation-induced delay of the cell cycle and DNA ploidy of the cell lines were also determined. For comparison an HeLa and a human foetal fibroblast cell line were simultaneously explored. Six previously cytogenetically and histologically characterized mesothelioma tumor cell lines were applied. A rapid tiazolyl blue microtiter (MTT) assay was used to analyze radiosensitivity and cell kinetics and DNA ploidy of the cultured cells were determined by flow cytometry. The survival fraction after a dose of 2 Gy (SF2), parameters alpha and beta of the linear quadratic model (LQ-model) and mean inactivation dose (D(MID)) were also estimated. The DNA index of four cell lines equaled 1.0 and two cell lines equaled 1.5 and 1.6. Different mesothelioma cell lines showed a great variation in radiosensitivity. Mean survival fraction after a radiation dose of 2 Gy (SF2) was 0.60 and ranged from 0.36 to 0.81 and mean alpha value was 0.26 (range 0.48 - 0.083). The SF2 of the most sensitive diploid mesothelioma cell line was 0.36: less than that of the foetal fibroblast cell line (0.49). The survival fractions (0.81 and 0.74) of the two most resistant cell lines, which also were aneuploid, were equal to that of the HeLa cell line (0.78). The alpha/beta ratios of the most sensitive cell lines were almost an order of magnitude greater than those of the two most resistant cell lines. Radiation-induced delay of the most resistant aneuploid cell line was similar to that of HeLa cells but in the most sensitive (diploid cells) there was practically no entry into the G1 phase following the 2 Gy radiation dose during 36 h.

Aneuploidy↗