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Localised spontaneous regression in mesothelioma — possible immunological mechanism
Lung Cancer 32 (2001) 197– 201 www.elsevier.nl/locate/lungcan
Case report
Localised spontaneous regression in mesothelioma — possible immunological mechanism B.W.S. Robinson *, C. Robinson, R.A. Lake Uni6ersity Department of Medicine, Uni6ersity of Western Australia, Sir Charles Gairdner Hospital, G Block, 4th Floor, Monash A6enue, Nedlands, Australia, 6009 Received 8 May 2000; received in revised form 5 September 2000; accepted 21 September 2000
Abstract Malignant mesothelioma (MM) is an aggressive tumor usually associated with asbestos exposure. Although it can remain stable for prolonged periods, it has not been described to spontaneously regress. MM tumors are thought to be immunogenic based both on animal studies and on the good responses in some humans treated with immunotherapy. Here we present a case of pleural MM in which a transient spontaneous regression was associated with tumor tissue infiltration with mononuclear cells and serological evidence of anti-MM reactivity. The patient’s tumor eventually progressed and with this progression there was evidence of loss of serological reactivity to some, but not all, of her MM antigens. The patient survived for 20 months and, in contrast to her initial biopsy, no significant lymphoid infiltrate was detected in her MM tissue at post mortem examination. © 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Mesothelioma; Regression; Tumor immunology; Western blotting; Antibodies
tenoom whilst working as a shop assistant and whilst handling her husband’s asbestos-contaminated workclothes between the age of 19–23 years. She was a non smoker.
1. Case report
1.1. Case Ms JL was a 54 year old woman who was noted to have a mid zone pleural-based opacity on routine chest X-ray, confirmed by CT scan (Fig. 1). Another smaller pleural mass was noted (visible in Fig. 1). She was incidentally exposed to crocidolite in the asbestos mining town of Wit* Corresponding author. Fax: + 61-8-93462816. E-mail address: [email protected] Robinson).
(B.W.S.
1.2. Pathology A standard thoracoscopy was performed and multiple pleural biopsies were taken of the large anterior lesion by direct biopsy. The tissue demonstrated malignant cells with large pleomorphic nuclei exhibiting very prominent nucleoli with abundant cytoplasm. Large numbers of small lymphocytes and scattered plasma cells were seen
0169-5002/01/$ - see front matter © 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S0169-5002(00)00217-8
198
B.W.S. Robinson et al. / Lung Cancer 32 (2001) 197–201
mixed with the tumor cells (Fig. 2A). The latter stained with CAM 5.2 (an epithelial– mesothelial marker) so the extent of the infiltrate was able to be confirmed using this antibody to distinguish tumour cells from lymphoid infiltrate (Fig. 2B). The tumour also stained with epithelial membrane antigen (EMA, an epithelial marker). The diagnosis of MM was confirmed by electron micoscopy, which showed large pleomorphic tumor cells and confirmed the presence of the infiltrate of numerous lymphocytes with scattered plasma cells. The tumor cell nuclei contained large prominent filamentous nucleoli. There were long, slender microvilli without glycocalyx on the surface. Desmosomes were well formed and some cells contained intracytoplasmic crypts with microvilli projecting into the lumen.
1.3. Course The patient had no therapy and underwent follow up CT scan 3 months after initial diagnosis with a view to enrolment in a clinical trial. To our surprise there was a marked spontaneous reduction in the size of the main CT scan lesion (Fig. 3A). The smaller posterior lesion remained unchanged in size (Fig. 3A). On further follow up, including thoracic CT scans at 2-monthly intervals, the posterior lesion gradually increased in
Fig. 1. Initial thoracic CT scan at presentation showing large anterior pleural-based nodule on the right side with a smaller posterior lesion.
size, (Fig. 3B) eventually progressing to encase the posterior and anterior surfaces of the lung. At no stage did the anterior lesion appear to regrow, although eventually that region was invaded by the progressing tumour. The patient received no anti-tumour treatment. Post mortern examination showed extensive MM with infiltration of the chest wall. The MM had mixed patterns with sarcomatoid, epithelial and desmoplastic areas. Immunohistochemistry showed staining for high molecular weight cytokeratin, EMA and vimentin. Asbestos body count revealed 308 asbestos bodies per gram lung weight in the apex of the left lower lobe.
1.4. Serological analysis No sera were available from the initial stage of her disease, but sera were obtained serially from the patient throughout the last 11 months of her disease. Western blot analysis was performed to monitor changes in the serological response to MM antigens (Fig. 4). Total cell lysate of a human MM cell line (Ju77; [2]) was separated by SDS –PAGE and transferred onto a nitrocellulose filter (Transblot, Bio Rad Laboratories, CA, USA). The filters were blocked in 5% low-fat milk powder in phosphate buffered saline (PBS) for 2 h at 4°C. Sera (acquired on the dates shown) were diluted 1/100 in the blocking solution and incubated with the blot at 4°C overnight with constant agitation. Blots were then washed four times for 30 min in PBST (PBS containing 0.1% Tween 20), then incubated with goat anti-human IgG conjugated to horseradish peroxidase (Sigma Chemical Company, NJ, USA) at a concentration of 1/2000 in PBST for 1 h at room temperature. After washing four times with PBST for 15 min, bound antibody was detected by the ECL chemiluminescence reaction (Amersham, UK) according to the manufacturer’s protocol. On initial examination of her sera, when the tumor was progressing, the patient exhibited a high titer anti-tumor response of moderate complexity. The complexity of the response had increased 2 months later but, over the following 7 months until just prior to her death from progres-
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199
Fig. 2. Tumor biopsy from the anterior lesion showing mesothelioma with a mononuclear cell infiltrate. (A) H&E stain showing cells with large pleomorphic nuclei with prominent nucleoli and abundant cytoplasm, consistent with mesothelioma. (B) Anti-cytokeratin stain (CAM5.2 — epithelial and mesothelial marker) staining, delineating the tumor cells (stained brown) from the mononuclear infiltrate.
sive disease, two of the anti-MM reactivities waned whereas one remained stable.
2. Discussion MM, a tumor of serosal surfaces, is increasing in incidence throughout the world, largely due to its causal link with asbestos [1]. Although MM is sometimes punctuated by a period of stability lasting several months, in over 700 cases seen at our hospital we have never seen spontaneous regression of this disease [1]. In the patient described, the histological features were clearly those of MM and this was confirmed by the subsequent clinical course and the post mortem examination of the tumor. The first point of interest in this case is the spontaneous regression of histologically confirmed MM tissue. This patient was asymptomatic and her tumor was detected on routine chest X-ray, i.e. if she had not had the routine chest X-ray the presence of the tumor masses which spontaneously regressed would not have been noted. This raises the possibility that other patients may have spontaneous regression of
transient tumors that are never detected. Intriguingly, the areas of tumor which spontaneously regressed never recurred — the posterior lesion, which failed to regress, eventually progressed and caused the patient’s death. Thus although spontaneous regression can occur, it is important to note that it is rare and transient. The second major point of interest in this case relates to the histopathological appearance of the tumor. ‘Lymphohistocytoid’ variant of this tumor is uncommon, representing less than 1% of all cases [3]. The detection of this pattern in the lesions which spontaneously regressed, and its absence from the progressive lesion noted at post mortem, provide strong circumstantial evidence that the mononuclear cell infiltrate was associated with the regression of the tumor. This is consistent with current concepts of immune response to tumors in humans and mice, where immune mediated regression of tumor is almost always associated with a mixed mononuclear cell infiltrate [4–6]. Current concepts of MM biology suggests that the tumor is, to some extent, immunogenic [7–10] and in patients with MM, clinical trials utilising immunomodulatory agents, such as recombinant interferon alpha, interferon gamma,
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B.W.S. Robinson et al. / Lung Cancer 32 (2001) 197–201
Fig. 3. Follow-up CT scans (A) 3 months after presentation, showing regression of the anterior mass only; (B) 16 months, showing progression of the posterior lesion only.
interleukin 2 and granulocyte macrophage colony stimulating factor, have all shown evidence of response in a proportion of patients [4,11– 14]. It is likely that the case presented here developed a spontaneous anti-MM immune response which effectively destroyed a number of tumor sites, associated with a lymphoid infiltrate, but this was transient. The reason for the failure of the single posterior nodule to be destroyed by the host anti-tumor response is unclear, and could represent either antigen loss, exclusion of effector lymphocytes from the site (that lesion was not biopsied), local over-production of immunosuppresive molecules or a number of other potential mechanisms [15]. The third interesting observation from this patient is the dynamic nature of the serological response. We have previously shown that approximately 30% of MM patients exhibit serological or immune reactivity to MM antigens [16] and this patient clearly reacted to the presence of MM antigens. No sera were available from the earliest stages of her disease but interestingly, with disease progression, the complexity of the humoral response to tumor autoantigens was seen to wax and wane, with at least two of the auto-antibody specificities disappearing from the serum while a third remained unchanged throughout the period of observation. Two possible explanations for this phenomenon are apparent. Firstly, that the response remained the same but was masked. This might occur if, for example, an increase in tumor cell death resulted in a massive increase in soluble
tumor antigen that effectively absorbed the antibody at a faster rate than it could be resynthesised. Alternatively, the particular B cell clones responsible for these specificities could have been silenced. This might occur by direct silencing (B cell deletion or B cell anergy) or indirectly by regulation of cognate T cell help [17]. In either case, the data are consistent with the hypothesis that disease progression resulted in the release of high concentrations of soluble tumor antigen, possibly via partial tumor necrosis, and that the pre-existing immune response was directed partly to such soluble antigens and partly to components of the insoluble fraction. The antibody response to the insoluble components was largely unaffected by increased tumor cell death.
Fig. 4. Western blot of serial serum samples from this patient showing changes in the humoral immune response to MM antigens. See main text for details.
B.W.S. Robinson et al. / Lung Cancer 32 (2001) 197–201
3. Conclusion This single case of MM, where spontaneous regression was associated with a lymphoid infiltrate and evidence of a serological response to the tumor, reinforces the notion that MM is a potentially immunogenic tumor. If the relevant MM tumor antigens can be identified and the most appropriate form of immunotherapy developed, regression of MM tumor masses is feasible, although strategies to avoid the tumor escaping from immune control will also need to be developed.
Acknowledgements RAL is a reciept of a James Hardie Industries fellowship.
References [1] Robinson BWS, Garlepp MJ, Scoff BI. Mesothelioma. In: Crystal RG, West JB, editors. The Lung: Scientific Foundations, 2nd edn. New York: Raven Press, 1995:2599 – 610. [2] Manning LS, Murch A, Garlepp MJ, Davis MR, Musk A, Robinson BWS. Establishment and characterisation of five human malignant mesothelioma cell lines derived from pleural effusions. Int J Cancer 1991;47:285 – 90. [3] Henderson DW, Attwood HD, Constance TJ, Shilkin KB, Steele RH. Lymphohistiocytoid mesothelioma: a rare lymphomatoid variant of predominantly sarcomatoid mesothelioma. Ultrastructural Pathol 1988;12:367 –84. [4] Davidson JA, Musk AW, Woodbaker R, et al. Intralesional cytokine therapy in cancer; a pilot study. J Immunother 1998;21:389 –98. [5] Caminschi I, Venetsanakos E, Leong CC, Garlepp MJ, Scott B, Robinson BWS. Interleukin-12 induces an effective anti-tumour response in malignant mesothelioma. Am J Resp Cell Mol Biol 1998;19:738 – 46.
.
201
[6] Caminschi I, Venetsanakos E, Leong CC, Garlepp MJ, Robinson BWS, Scott B. Cytokine gene therapy of mesothelioma: Immune and anti-tumor effects of transfected IL12. Am J Resp Cell Mol Biol 1999;21:347 – 56. [7] Upham J, Garlepp MJ, Musk AW, Robinson BWS. Malignant mesothelioma: new insights into tumour biology and immunology as a basis for new treatment approaches. Thorax 1995;50:887 – 93. [8] Robinson BWS, Davidson JA, Garlepp MJ. The Immunology and Immunopathology of Malignant Mesothelioma. In: Kradin RL, Robinson BWS, editors. Immunopathology of lung disease. Stoneham, MA: Butterworth Heinemann, 1996:491 – 513. [9] Leong CC, Marley JV, Loh S, Robinson BWS, Garlepp MJ. Induction and maintenance of T cell response to a nonimmunogenic murine mesothelioma cell line requires expression of B7-1 and the capacity to upregulate class II major histocompatibility complex expression. Cancer Gene Ther 1996;3:321 – 30. [10] Marzo AL, Lake RA, Robinson BWS, Scott B. T-cell receptor transgenic analysis of tumor-specific CD8 and CD4 responses in the eradication of solid tumours. Cancer Res 1999;59:1071 – 9. [11] Christmas TI, Manning LS, Garlepp MJ, Musk AW, Robinson BWS. Effect of Interferon a-2a on malignant mesothelioma. J Interferon Res 1993;13:9 – 12. [12] Boutin C, Nussbaum E, Monnet I, et al. Intrapleural treatment with recombinant gamma-interferon in early stage malignant pleural mesothelioma. Cancer 1994;74:2460 – 7. [13] Robinson BWS, Bowman RV, Manning LS, Musk AW, Van Hazel GA. Interleukin-2 and lymphokine-activated killer cells in malignant mesothelioma. Eur Resp Rev 1993;3:220 – 2. [14] Robinson BWS, Mukherjee S, Davidson A, et al. Cytokine gene therapy or infusion as treatment for solid human cancer. J Immunother 1998;21:211 – 7. [15] Fitzpatrick DR, Bielefeldt-Ohmann H, Himbeck RIP, Jarnicki AG, Marzo AL, Robinson BWS. Transforming growth factor-beta: antisense RNA-mediated inhibition affects anchorage-independent growth, tumorigenicity and tumour-infiltrating T-cells in malignant mesothelioma. Growth Factors 1994;11:29 – 44. [16] Robinson C, Robinson BWS, Lake RA. Sera from patients with malignant mesothelioma contain autoantibodies. Lung Cancer 1998;20:175 – 84. [17] Hodgkin PD, Basten A. B cell activation, tolerance and antigen-presenting function. Curr Opin Immunol 1995;7:121 – 9.
Case report
Localised spontaneous regression in mesothelioma — possible immunological mechanism B.W.S. Robinson *, C. Robinson, R.A. Lake Uni6ersity Department of Medicine, Uni6ersity of Western Australia, Sir Charles Gairdner Hospital, G Block, 4th Floor, Monash A6enue, Nedlands, Australia, 6009 Received 8 May 2000; received in revised form 5 September 2000; accepted 21 September 2000
Abstract Malignant mesothelioma (MM) is an aggressive tumor usually associated with asbestos exposure. Although it can remain stable for prolonged periods, it has not been described to spontaneously regress. MM tumors are thought to be immunogenic based both on animal studies and on the good responses in some humans treated with immunotherapy. Here we present a case of pleural MM in which a transient spontaneous regression was associated with tumor tissue infiltration with mononuclear cells and serological evidence of anti-MM reactivity. The patient’s tumor eventually progressed and with this progression there was evidence of loss of serological reactivity to some, but not all, of her MM antigens. The patient survived for 20 months and, in contrast to her initial biopsy, no significant lymphoid infiltrate was detected in her MM tissue at post mortem examination. © 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Mesothelioma; Regression; Tumor immunology; Western blotting; Antibodies
tenoom whilst working as a shop assistant and whilst handling her husband’s asbestos-contaminated workclothes between the age of 19–23 years. She was a non smoker.
1. Case report
1.1. Case Ms JL was a 54 year old woman who was noted to have a mid zone pleural-based opacity on routine chest X-ray, confirmed by CT scan (Fig. 1). Another smaller pleural mass was noted (visible in Fig. 1). She was incidentally exposed to crocidolite in the asbestos mining town of Wit* Corresponding author. Fax: + 61-8-93462816. E-mail address: [email protected] Robinson).
(B.W.S.
1.2. Pathology A standard thoracoscopy was performed and multiple pleural biopsies were taken of the large anterior lesion by direct biopsy. The tissue demonstrated malignant cells with large pleomorphic nuclei exhibiting very prominent nucleoli with abundant cytoplasm. Large numbers of small lymphocytes and scattered plasma cells were seen
0169-5002/01/$ - see front matter © 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S0169-5002(00)00217-8
198
B.W.S. Robinson et al. / Lung Cancer 32 (2001) 197–201
mixed with the tumor cells (Fig. 2A). The latter stained with CAM 5.2 (an epithelial– mesothelial marker) so the extent of the infiltrate was able to be confirmed using this antibody to distinguish tumour cells from lymphoid infiltrate (Fig. 2B). The tumour also stained with epithelial membrane antigen (EMA, an epithelial marker). The diagnosis of MM was confirmed by electron micoscopy, which showed large pleomorphic tumor cells and confirmed the presence of the infiltrate of numerous lymphocytes with scattered plasma cells. The tumor cell nuclei contained large prominent filamentous nucleoli. There were long, slender microvilli without glycocalyx on the surface. Desmosomes were well formed and some cells contained intracytoplasmic crypts with microvilli projecting into the lumen.
1.3. Course The patient had no therapy and underwent follow up CT scan 3 months after initial diagnosis with a view to enrolment in a clinical trial. To our surprise there was a marked spontaneous reduction in the size of the main CT scan lesion (Fig. 3A). The smaller posterior lesion remained unchanged in size (Fig. 3A). On further follow up, including thoracic CT scans at 2-monthly intervals, the posterior lesion gradually increased in
Fig. 1. Initial thoracic CT scan at presentation showing large anterior pleural-based nodule on the right side with a smaller posterior lesion.
size, (Fig. 3B) eventually progressing to encase the posterior and anterior surfaces of the lung. At no stage did the anterior lesion appear to regrow, although eventually that region was invaded by the progressing tumour. The patient received no anti-tumour treatment. Post mortern examination showed extensive MM with infiltration of the chest wall. The MM had mixed patterns with sarcomatoid, epithelial and desmoplastic areas. Immunohistochemistry showed staining for high molecular weight cytokeratin, EMA and vimentin. Asbestos body count revealed 308 asbestos bodies per gram lung weight in the apex of the left lower lobe.
1.4. Serological analysis No sera were available from the initial stage of her disease, but sera were obtained serially from the patient throughout the last 11 months of her disease. Western blot analysis was performed to monitor changes in the serological response to MM antigens (Fig. 4). Total cell lysate of a human MM cell line (Ju77; [2]) was separated by SDS –PAGE and transferred onto a nitrocellulose filter (Transblot, Bio Rad Laboratories, CA, USA). The filters were blocked in 5% low-fat milk powder in phosphate buffered saline (PBS) for 2 h at 4°C. Sera (acquired on the dates shown) were diluted 1/100 in the blocking solution and incubated with the blot at 4°C overnight with constant agitation. Blots were then washed four times for 30 min in PBST (PBS containing 0.1% Tween 20), then incubated with goat anti-human IgG conjugated to horseradish peroxidase (Sigma Chemical Company, NJ, USA) at a concentration of 1/2000 in PBST for 1 h at room temperature. After washing four times with PBST for 15 min, bound antibody was detected by the ECL chemiluminescence reaction (Amersham, UK) according to the manufacturer’s protocol. On initial examination of her sera, when the tumor was progressing, the patient exhibited a high titer anti-tumor response of moderate complexity. The complexity of the response had increased 2 months later but, over the following 7 months until just prior to her death from progres-
B.W.S. Robinson et al. / Lung Cancer 32 (2001) 197–201
199
Fig. 2. Tumor biopsy from the anterior lesion showing mesothelioma with a mononuclear cell infiltrate. (A) H&E stain showing cells with large pleomorphic nuclei with prominent nucleoli and abundant cytoplasm, consistent with mesothelioma. (B) Anti-cytokeratin stain (CAM5.2 — epithelial and mesothelial marker) staining, delineating the tumor cells (stained brown) from the mononuclear infiltrate.
sive disease, two of the anti-MM reactivities waned whereas one remained stable.
2. Discussion MM, a tumor of serosal surfaces, is increasing in incidence throughout the world, largely due to its causal link with asbestos [1]. Although MM is sometimes punctuated by a period of stability lasting several months, in over 700 cases seen at our hospital we have never seen spontaneous regression of this disease [1]. In the patient described, the histological features were clearly those of MM and this was confirmed by the subsequent clinical course and the post mortem examination of the tumor. The first point of interest in this case is the spontaneous regression of histologically confirmed MM tissue. This patient was asymptomatic and her tumor was detected on routine chest X-ray, i.e. if she had not had the routine chest X-ray the presence of the tumor masses which spontaneously regressed would not have been noted. This raises the possibility that other patients may have spontaneous regression of
transient tumors that are never detected. Intriguingly, the areas of tumor which spontaneously regressed never recurred — the posterior lesion, which failed to regress, eventually progressed and caused the patient’s death. Thus although spontaneous regression can occur, it is important to note that it is rare and transient. The second major point of interest in this case relates to the histopathological appearance of the tumor. ‘Lymphohistocytoid’ variant of this tumor is uncommon, representing less than 1% of all cases [3]. The detection of this pattern in the lesions which spontaneously regressed, and its absence from the progressive lesion noted at post mortem, provide strong circumstantial evidence that the mononuclear cell infiltrate was associated with the regression of the tumor. This is consistent with current concepts of immune response to tumors in humans and mice, where immune mediated regression of tumor is almost always associated with a mixed mononuclear cell infiltrate [4–6]. Current concepts of MM biology suggests that the tumor is, to some extent, immunogenic [7–10] and in patients with MM, clinical trials utilising immunomodulatory agents, such as recombinant interferon alpha, interferon gamma,
200
B.W.S. Robinson et al. / Lung Cancer 32 (2001) 197–201
Fig. 3. Follow-up CT scans (A) 3 months after presentation, showing regression of the anterior mass only; (B) 16 months, showing progression of the posterior lesion only.
interleukin 2 and granulocyte macrophage colony stimulating factor, have all shown evidence of response in a proportion of patients [4,11– 14]. It is likely that the case presented here developed a spontaneous anti-MM immune response which effectively destroyed a number of tumor sites, associated with a lymphoid infiltrate, but this was transient. The reason for the failure of the single posterior nodule to be destroyed by the host anti-tumor response is unclear, and could represent either antigen loss, exclusion of effector lymphocytes from the site (that lesion was not biopsied), local over-production of immunosuppresive molecules or a number of other potential mechanisms [15]. The third interesting observation from this patient is the dynamic nature of the serological response. We have previously shown that approximately 30% of MM patients exhibit serological or immune reactivity to MM antigens [16] and this patient clearly reacted to the presence of MM antigens. No sera were available from the earliest stages of her disease but interestingly, with disease progression, the complexity of the humoral response to tumor autoantigens was seen to wax and wane, with at least two of the auto-antibody specificities disappearing from the serum while a third remained unchanged throughout the period of observation. Two possible explanations for this phenomenon are apparent. Firstly, that the response remained the same but was masked. This might occur if, for example, an increase in tumor cell death resulted in a massive increase in soluble
tumor antigen that effectively absorbed the antibody at a faster rate than it could be resynthesised. Alternatively, the particular B cell clones responsible for these specificities could have been silenced. This might occur by direct silencing (B cell deletion or B cell anergy) or indirectly by regulation of cognate T cell help [17]. In either case, the data are consistent with the hypothesis that disease progression resulted in the release of high concentrations of soluble tumor antigen, possibly via partial tumor necrosis, and that the pre-existing immune response was directed partly to such soluble antigens and partly to components of the insoluble fraction. The antibody response to the insoluble components was largely unaffected by increased tumor cell death.
Fig. 4. Western blot of serial serum samples from this patient showing changes in the humoral immune response to MM antigens. See main text for details.
B.W.S. Robinson et al. / Lung Cancer 32 (2001) 197–201
3. Conclusion This single case of MM, where spontaneous regression was associated with a lymphoid infiltrate and evidence of a serological response to the tumor, reinforces the notion that MM is a potentially immunogenic tumor. If the relevant MM tumor antigens can be identified and the most appropriate form of immunotherapy developed, regression of MM tumor masses is feasible, although strategies to avoid the tumor escaping from immune control will also need to be developed.
Acknowledgements RAL is a reciept of a James Hardie Industries fellowship.
References [1] Robinson BWS, Garlepp MJ, Scoff BI. Mesothelioma. In: Crystal RG, West JB, editors. The Lung: Scientific Foundations, 2nd edn. New York: Raven Press, 1995:2599 – 610. [2] Manning LS, Murch A, Garlepp MJ, Davis MR, Musk A, Robinson BWS. Establishment and characterisation of five human malignant mesothelioma cell lines derived from pleural effusions. Int J Cancer 1991;47:285 – 90. [3] Henderson DW, Attwood HD, Constance TJ, Shilkin KB, Steele RH. Lymphohistiocytoid mesothelioma: a rare lymphomatoid variant of predominantly sarcomatoid mesothelioma. Ultrastructural Pathol 1988;12:367 –84. [4] Davidson JA, Musk AW, Woodbaker R, et al. Intralesional cytokine therapy in cancer; a pilot study. J Immunother 1998;21:389 –98. [5] Caminschi I, Venetsanakos E, Leong CC, Garlepp MJ, Scott B, Robinson BWS. Interleukin-12 induces an effective anti-tumour response in malignant mesothelioma. Am J Resp Cell Mol Biol 1998;19:738 – 46.
.
201
[6] Caminschi I, Venetsanakos E, Leong CC, Garlepp MJ, Robinson BWS, Scott B. Cytokine gene therapy of mesothelioma: Immune and anti-tumor effects of transfected IL12. Am J Resp Cell Mol Biol 1999;21:347 – 56. [7] Upham J, Garlepp MJ, Musk AW, Robinson BWS. Malignant mesothelioma: new insights into tumour biology and immunology as a basis for new treatment approaches. Thorax 1995;50:887 – 93. [8] Robinson BWS, Davidson JA, Garlepp MJ. The Immunology and Immunopathology of Malignant Mesothelioma. In: Kradin RL, Robinson BWS, editors. Immunopathology of lung disease. Stoneham, MA: Butterworth Heinemann, 1996:491 – 513. [9] Leong CC, Marley JV, Loh S, Robinson BWS, Garlepp MJ. Induction and maintenance of T cell response to a nonimmunogenic murine mesothelioma cell line requires expression of B7-1 and the capacity to upregulate class II major histocompatibility complex expression. Cancer Gene Ther 1996;3:321 – 30. [10] Marzo AL, Lake RA, Robinson BWS, Scott B. T-cell receptor transgenic analysis of tumor-specific CD8 and CD4 responses in the eradication of solid tumours. Cancer Res 1999;59:1071 – 9. [11] Christmas TI, Manning LS, Garlepp MJ, Musk AW, Robinson BWS. Effect of Interferon a-2a on malignant mesothelioma. J Interferon Res 1993;13:9 – 12. [12] Boutin C, Nussbaum E, Monnet I, et al. Intrapleural treatment with recombinant gamma-interferon in early stage malignant pleural mesothelioma. Cancer 1994;74:2460 – 7. [13] Robinson BWS, Bowman RV, Manning LS, Musk AW, Van Hazel GA. Interleukin-2 and lymphokine-activated killer cells in malignant mesothelioma. Eur Resp Rev 1993;3:220 – 2. [14] Robinson BWS, Mukherjee S, Davidson A, et al. Cytokine gene therapy or infusion as treatment for solid human cancer. J Immunother 1998;21:211 – 7. [15] Fitzpatrick DR, Bielefeldt-Ohmann H, Himbeck RIP, Jarnicki AG, Marzo AL, Robinson BWS. Transforming growth factor-beta: antisense RNA-mediated inhibition affects anchorage-independent growth, tumorigenicity and tumour-infiltrating T-cells in malignant mesothelioma. Growth Factors 1994;11:29 – 44. [16] Robinson C, Robinson BWS, Lake RA. Sera from patients with malignant mesothelioma contain autoantibodies. Lung Cancer 1998;20:175 – 84. [17] Hodgkin PD, Basten A. B cell activation, tolerance and antigen-presenting function. Curr Opin Immunol 1995;7:121 – 9.