Multipoint targeting of the PI3K/mTOR pathway in mesothelioma

BACKGROUND

Mesothelioma is a notoriously chemotherapy-resistant neoplasm, as is evident in the dismal overall survival for patients with those of asbestos-associated disease. We previously demonstrated co-activation of multiple receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR), MET, and AXL in mesothelioma cell lines, suggesting that these kinases could serve as novel therapeutic targets. Although clinical trials have not shown activity for EGFR inhibitors in mesothelioma, concurrent inhibition of various activated RTKs has pro-apoptotic and anti-proliferative effects in mesothelioma cell lines. Thus, we hypothesised that a coordinated network of multi-RTK activation contributes to mesothelioma tumorigenesis.

METHODS

Activation of PI3K/AKT/mTOR, Raf/MAPK, and co-activation of RTKs were evaluated in mesotheliomas. Effects of RTK and downstream inhibitors/shRNAs were assessed by measuring mesothelioma cell viability/growth, apoptosis, activation of signalling intermediates, expression of cell-cycle checkpoints, and cell-cycle alterations.

RESULTS

We demonstrate activation of the PI3K/AKT/p70S6K and RAF/MEK/MAPK pathways in mesothelioma, but not in non-neoplastic mesothelial cells. The AKT activation, but not MAPK activation, was dependent on coordinated activation of RTKs EGFR, MET, and AXL. In addition, PI3K/AKT/mTOR pathway inhibition recapitulated the anti-proliferative effects of concurrent inhibition of EGFR, MET, and AXL. Dual targeting of PI3K/mTOR by BEZ235 or a combination of RAD001 and AKT knockdown had a greater effect on mesothelioma proliferation and viability than inhibition of individual activated RTKs or downstream signalling intermediates. Inhibition of PI3K/AKT was also associated with MDM2-p53 cell-cycle regulation.

CONCLUSIONS

These findings show that PI3K/AKT/mTOR is a crucial survival pathway downstream of multiple activated RTKs in mesothelioma, underscoring that PI3K/mTOR is a compelling target for therapeutic intervention.

Impact of pathological staging on survival in patients with epithelial mesothelioma treated with extrapleural pneumonectomy

7706

Objective: There is no universally accepted staging system in malignant pleural mesothelioma (MPM). A seventeen-year single institution experience of surgically treating a large epithelial MPM cohort with extrapleural pneumonectomy (EPP) gives insight to the applications and limitations of BWH/ DFCI and AJCC staging systems. Methods: We retrospectivly reviewed 526 consecutive patients with epithelial MPM who were surgically explored at our institution since 1988 with intent to perform EPP. Pathologic diagnoses of mesothelioma were confirmed and clinicopathologic data were recorded. Kaplan-Meyer survival from diagnosis was calculated. Those who underwent EPP were staged using BWH / DFCI (J Thorac Cardiov Surg 117:5463;1999) and AJCC (6th Edition) criteria. Operative deaths were included in the analysis and patients received varied adjuvant regimens. Results: Of 526 patients explored for potential EPP, 53 (10%) underwent alternative pleurectomy and 55 (11%) were unresectable. The remaining 418 (79%) underwent EPP. Of these, 307 (73%) were male. Median age at diagnosis was 57.9 years (17–78). Operative mortality was 5%. Median follow-up was 16 months and 23% of observations were censored. Overall median, 1-yr, 3-yr and 5-yr survival was: 18.9 mo., 68.8%, 26.3%, and 13.9%. The table below presents Kaplan-Meyer survival by stage. Conclusions: 1) Both pathological staging systems stratify survival in this cohort, although each system is limited in that a majority of patients are classified as stage 3. 2) BWH / DFCI criteria identify more stage 1–2 patients with favorable prognosis, 164 (39%) vs 46 (11%). 3) AJCC criteria classify more patients to stage 4, 76 (18%) vs 4 (1%), but appear to identify some patients with relatively favorable prognosis. 4) Selected criteria from both systems might be combined to optimally stratify patients with epithelial MPM undergoing EPP.

No significant financial relationships to disclose.

[Table: see text]

Resection margins, extrapleural nodal status, and cell type determine postoperative long-term survival in trimodality therapy of malignant pleural mesothelioma: results in 183 patients

OBJECTIVES

Our aim was to identify prognostic variables for long-term postoperative survival in trimodality management of malignant pleural mesothelioma.

METHODS

From 1980 to 1997, 183 patients underwent extrapleural pneumonectomy followed by adjuvant chemotherapy and radiotherapy.

RESULTS

Forty-three women and 140 men (age range 31-76 years) had a median follow-up of 13 months. The perioperative mortality rate was 3.8% (7 deaths) and the morbidity, 50%. Survival in the 176 remaining patients was 38% at 2 years and 15% at 5 years (median 19 months). Univariate analysis identified 3 prognostic variables associated with improved survival: epithelial cell type (52% 2-year survival, 21% 5-year survival, 26-month median survival; P =.0001), negative resection margins (44% at 2 years, 25% at 5 years, median 23 months; P =.02), and extrapleural nodes without metastases (42% at 2 years, 17% at 5 years, median 21 months; P =.004). Using the Cox proportional hazards, the relative risk of death was calculated for nonepithelial cell type (OR 3.0, CI 2.0-4.5; P <.0001), positive resection margins (OR 1.7, CI 1.2-2.6; P =.0082), and metastatic extrapleural nodes (OR 2.0, CI 1.3-3.2; P =.0026). Thirty-one patients with 3 positive variables had the best survival (68% 2-year survival, 46% 5-year survival, median 51 months; P =.013). A previously published staging system using these variables stratified survival (P <.05).

CONCLUSIONS

(1) Multimodality therapy including extrapleural pneumonectomy is feasible in selected patients with malignant pleural mesotheliomas, (2) pre-resectional evaluation of extrapleural nodes may select patients for radical therapy, (3) microscopic resection margins affect long-term survival, highlighting the need for further investigation of locoregional control, and (4) patients with epithelial, margin-negative, extrapleural node-negative resection had extended survival.

Dihydro-5-azacytidine and cisplatin in the treatment of malignant mesothelioma: a phase II study by the Cancer and Leukemia Group B

BACKGROUND

In a prior Cancer and Leukemia Group B (CALGB) Phase II trial of patients with advanced, previously untreated mesothelioma, dihydro-5-azacytidine (DHAC) demonstrated a 17% response rate, including 1 complete response, with only mild myelosuppression. This Phase II study (CALGB 9031) was conducted to determine the effectiveness of and toxicities that would result from adding cisplatin to DHAC administered to the same patient population.

METHODS

Thirty-six patients were treated with concurrent DHAC at 1500 mg/m2/day for 5 days by continuous infusion and cisplatin 15 mg/m2 daily for 5 days. Therapy was repeated every 3 weeks. Cisplatin was to be increased to 20 mg/m2 daily in subsequent cycles if toxicity was minimal. Therapy was continued until disease progression or excessive toxicity mandated discontinuation.

RESULTS

Overall, 5 objective responses were observed in 29 evaluated patients (objective response rate, 17%). The median duration of response was 6.6 months. Median survival was 6.4 months, with a median time to clinical failure of 2.7 months. The major toxicity noted was significant chest/pericardial pain, as was observed with DHAC alone. There were 2 early deaths of unknown cause on Days 9 and 17 of therapy, respectively. Significant leukopenia was observed in 29% of patients, but there were no neutropenic fevers.

CONCLUSIONS

The addition of cisplatin to DHAC did not increase the response rate over that observed with DHAC alone in patients with mesothelioma; however, it did increase toxicity, especially leukopenia. This combination is not recommended for further studies involving mesothelioma patients.

Factors predictive of survival among 337 patients with mesothelioma treated between 1984 and 1994 by the Cancer and Leukemia Group B

PURPOSE

To examine the individual and joint effect of various pretreatment clinical characteristics on the survival of patients with mesothelioma treated by the Cancer and Leukemia Group B (CALGB).

PATIENTS AND METHODS

Between June 1984 and September 1994, 337 patients with malignant mesothelioma and no prior chemotherapy were accrued to seven phase II studies conducted by the CALGB which screened the efficacy of 10 treatment regimens or dose levels. The eligibility criteria for all studies were virtually identical. Patient characteristics include the following: age older than 60 years (63%); male (83%); performance status (PS) of 0 or 1 (81%); chest pain (60%); definite asbestos exposure (62%); >5% weight loss (41%); and pleural involvement (94%). Median survival time (MST) for the 10 treatment regimens ranged from 3.9 to 9.8 months (overall=7.2; 95% confidence interval [CI], 6.5 to 8.3), with 1-year survival between 14% and 50% (overall=27%; 95% CI, 23 to 33%).

RESULTS

Cox survival models and exponential regression trees were used to examine the prognostic importance of pretreatment patient characteristics. Univariate analyses show that patients with poor Eastern Cooperative Oncology Group PS, chest pain, dyspnea, platelet count (PLT) >400,000/microL, weight loss, serum lactate dehydrogenase (LDH) level >500 IU/L, pleural involvement, low hemoglobin (HGB) level, high WBC count, and increasing age over 75 years have a worse prognosis. With decreasing risk ratio, multivariate Cox analyses showed that pleural involvement, LDH >500 IU/L, poor PS, chest pain, PLT >400,000/microL, nonepithelial histology, and increasing age older than 75 years jointly predict poor survival. PS was the most important prognostic split in the regression tree. Terminal nodes were amalgamated to form six distinct prognostic subgroups with MST (2-year survival) of 13.9 (38%) in 36 patients, 9.5 (21%) in 36 patients, 9.2 (10%) in 146 patients, 6.5 (3%) in 33 patients, 4.4 (0%) in 73 patients, and 1.4 (0%) in 13 patients (p<0.0001).

CONCLUSIONS

The subgroup with the best survival (MST=13.9 months) included patients with PS=0 and age younger than 49 years, and patients with PS=0, age of 49 years or older, and HGB > or =14.6. The worst survival (MST= 1.4 months) occurred for patients with PS= 1/2 and WBC > or =15.6/microL.

Pathology of diffuse malignant pleural mesothelioma

An accurate diagnosis is essential to a rational approach to the treatment of diffuse malignant pleural mesothelioma and generally requires pathological examination with the application of special techniques. In recent years, immunohistochemistry has greatly abetted the distinction of mesothelioma from its many morphological mimics, yet diagnostic difficulties still remain because reactive hyperplasias and diverse tumors closely mimic mesothelioma. Mesotheliomas are classified into epithelial, mixed, sarcomatoid and undifferentiated types, based on conventional histological examination. The classification provides important prognostic information. Furthermore, differential diagnosis is directly related to histological type. Although such special techniques as histochemistry and electron microscopy continue to play an important role in some cases, immunohistochemistry often has replaced these in distinguishing epithelial-type mesothelioma from metastatic adenocarcinoma. It is also helpful in distinguishing sarcomatoid mesothelioma from it numerous morphological mimics. The distinction of mesothelioma from reactive mesothelial proliferations is still based on morphological examination and may be quite problematic. Recent cytogenetic studies, which have identified characteristic clonal deletions in mesotheliomas, give promise of providing valuable assistance in this distinction in the future.

Dihydro-5-azacytidine in malignant mesothelioma. A phase II trial demonstrating activity accompanied by cardiac toxicity. Cancer and Leukemia Group B

BACKGROUND

Malignant mesothelioma is a disease that is refractory to chemotherapy. Therefore, the objective of this multi-institutional, cooperative group Phase II trial was to determine the efficacy of dihydro-5-azacytidine (DHAC), a pyrimidine analogue, in the treatment of malignant mesothelioma.

METHODS

Forty-one patients with histologically confirmed malignant mesothelioma received 120-hour continuous infusions of DHAC (1,500 mg/m2/day every 21 days) until maximal response, intolerable toxicity, or disease progression.

RESULTS

One patient had a complete response, two had objective partial responses, and four had regression of evaluable disease. The overall response rate was 17%. The one complete responder remains without disease progression at 6 years. Chest pain and nausea were the most common toxicities. Supraventricular tachycardia and pericardial effusion occurred in 20% and 15% of patients, respectively. In most patients, gastrointestinal effects were manageable. There was no significant hematologic toxicity.

CONCLUSIONS

In malignant mesothelioma, a disease that is refractory to chemotherapy, dihydro-5-azacytidine has definite antitumor activity. Its modest hematologic toxicity profile favors its use in combination with other agents. Caution regarding cardiac arrhythmias and pericardial effusion is necessary.

1H-NMR detectable fatty acyl chain unsaturation in excised leiomyosarcoma correlate with grade and mitotic activity

We report on the use of 1H-NMR two-dimensional total correlated spectroscopy (2D TOCSY) at 600 MHz for an ex vivo analysis of fatty acyl chain lipid in normal smooth muscle and a series of primary retroperitoneal leiomyosarcomas. These TOCSY spectra were used to identify and quantitate the methylene protons situated between unsaturated site protons (D) to those bordered by only one unsaturated site proton (C). The D/C cross-peak volume ratios determined for oleic (18:1), linoleic (18:2), linolenic (18:3), and arachidonic (20:4) acids were 0.0, 1.3, 2.7, and 4.0, respectively, suggesting that this ratio can be a measure of the degree of unsaturation for fatty acyl chains of lipids. The D/C cross-peak volume ratio was found to be proportional to the mean mitotic activity (r = 0.94) in nine smooth muscle tissues. These results suggest, that for leiomyosarcoma, the degree of fatty acyl unsaturation may be an important determinant of the metastatic potential of these tumors. Furthermore, application of TOCSY for the ex vivo study of smooth muscle tumors would potentially serve as a pathologist-independent and quantitative method for assessment of leiomyosarcoma grade and mitotic activity thereby rendering a more accurate staging of patients.

Malignant mesothelioma following treatment for Hodgkin's disease

PURPOSE

Asbestos exposure is the major known risk factor for mesothelioma, but several case reports have suggested a link between radiation therapy and subsequent development of malignant mesothelioma. This report explores a possible association between radiation therapy for Hodgkin's disease and mesothelioma.

PATIENTS AND METHODS

Four cases of malignant mesothelioma were observed following Hodgkin's disease at the Mesothelioma Clinic of the Dana-Farber Cancer Institute. A fifth such patient was found after a review of the literature.

RESULTS

In all five cases, the mesothelioma arose in the field of prior radiotherapy. No history of asbestos exposure was elicited by careful questioning or by review of chest radiographs. Examination of lung tissue in one patient showed 250 ferruginous bodies per gram of lung tissue, consistent with no significant prior exposure. The mean interval between radiation treatment for Hodgkin's disease and development of mesothelioma was 15 years, which emphasizes the need for continued follow-up and evaluation of these patients and supports a causal relationship.

CONCLUSION

Mesothelioma may need to be added to the list of second malignancies that arise following radiation therapy for Hodgkin's disease. Further support is given to a causal link between radiation exposure and mesothelioma.

Synovial sarcoma: prognostic significance of tumor size, margin of resection, and mitotic activity for survival

PURPOSE

The present study serves to describe outcomes-based prognostic variables characteristic of synovial cell sarcoma.

PATIENTS AND METHODS

An analysis was performed of a prospectively compiled data base of 48 consecutive patients with extremity and truncal synovial sarcomas seen between 1966 and 1994.

RESULTS

No local recurrences were observed among 27 patients who presented with localized primary disease. Patients with synovial sarcoma less than 5 cm in size has a cancer-specific survival rate at 10 years of 100%, compared with a 10-year survival rate of 32% and 0% for those with sarcoma 5 to 10 cm and greater than 10 cm, respectively (P = .002). Patients with synovial sarcoma with less than 10 mitoses per 10 high-power fields (hpf) had a 10-year cancer-specific survival rate of 46%, compared with a 10-year survival rate of 14% for those with sarcomas with greater than 10 mitoses per hpf (P = .04). Patients with a clean margin of excision were found to have a 10-year cancer-specific survival rate of 43%, compared with 0% for those with microscopic positive margins (P = .03). Among 14 patients treated with neoadjuvant chemotherapy, seven (50%) had objective responses.

CONCLUSION

Local control for patients with nonmetastatic disease was excellent. The overall cancer-specific survival rate for patients with localized synovial sarcoma was 34% at 10 years. Primary tumor size, margin of resection, and mean mitotic activity were prognostic factors for survival in synovial sarcoma. There was a high objective response rate to treatment with neoadjuvant chemotherapy; however, there was no detectable beneficial effects on survival in the subset of patients treated with chemotherapy versus nonrandomized patients who received no chemotherapy. Patients with synovial sarcoma > or = 5 cm in size, microscopic positive margins, and/or mean mitotic activity greater than 10 mitoses per 10 hpf should be targeted for new therapeutic studies.

Ring chromosomes in dermatofibrosarcoma protuberans are composed of interspersed sequences from chromosomes 17 and 22

Ring chromosomes are found in most dermatofibrosarcoma protuberans (DFSPs), and recent reports demonstrate that portions of the DFSP ring chromosomes derive from chromosome 17. In this study we characterized ring chromosomes in three DFSPs using a combined approach of karyotyping, chromosome painting, and comparative genomic hybridization. Chromosome painting demonstrated that the ring chromosomes in each DFSP were composed of discontinuous, interwoven sequences from chromosomes 17 and 22. Amplification of chromosomes 17 and 22 sequences was confirmed in each of these cases by comparative genomic hybridization, and over-representation of chromosomes 17 and 22 sequences was also demonstrated by comparative genomic hybridization in 1 of 2 cytogenetically unremarkable DFSPs. We conclude that amplification of chromosomes 17 and 22 sequences, in ring form, is a characteristic aberration in DFSP.

Detection of chromosome 18 rearrangement in synovial sarcoma by fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) evaluations of chromosome 18 were performed in synovial sarcoma, hemangiopericytoma, and mesothelioma. Each case was evaluated with centromeric and whole chromosome paint probes. The synovial sarcomas had t(X;18) cytogenetically, but the FISH evaluator was blinded to the cytogenetic results and to the histopathologic diagnosis. The FISH analyses were consistent with chromosome 18 translocation in 6 of 7 synovial sarcomas, 0 of 3 hemangiopericytomas, and 0 of 1 mesothelioma. These findings support the use of FISH in the diagnosis of synovial sarcoma.

Codeletion of p15 and p16 in primary malignant mesothelioma

The p15 and p16 CDK4 inhibitor genes map within the chromosome band 9p21 region deleted frequently in malignant mesothelioma and other cancers. p16 has been implicated recently as a potential target of 9p21 deletions in mesothelioma, but the role of this gene is uncertain because deletions have been detected more often in established cell lines than in primary tumor specimens. We determined p15 and p16 copy number by fluorescence in situ hybridization with a P1 contig in 50 primary mesotheliomas. Codeletion of p15 and p16 was found in 72% of mesotheliomas, including all cases with spindle-cell components (n = 21) and total deletion of p15 and p16 was found in several mesotheliomas that lacked cytogenetic deletion of the chromosome 9 short arm. Point mutations were not found, however, in exon 2 of retained p15 and p16 alleles from seven mesotheliomas. These findings demonstrate that p15, p16 and/or a closely neighboring gene, are the targets of frequent chromosome 9p deletion in primary malignant mesothelioma.

Codeletion of p15 and p16 genes in primary non-small cell lung carcinoma

Chromosome band 9p21 is deleted frequently in non-small cell lung carcinoma (NSCLC), and the p15 and p16 cyclin-dependent kinase-4 inhibitor genes map within this deletion region. Recent studies demonstrated deletion of p15 and p16 in NSCLC metastases and cell lines, suggesting a role for these genes in NSCLC progression. We now report p15 and p16 copy number, as determined by fluorescence in situ hybridization with a P1 contig, in 18 primary NSCLCs. Codeletion of p15 and p16 was found in 15 of 18 NSCLCs, and 1 of the 3 tumors with normal p15 and p16 copy number had a nonsense mutation in exon 2 of p16. We conclude that p15 and p16 are deleted and/or mutated in most primary NSCLCs. Two observations, however, support the involvement of at least one additional tumor suppressor gene on chromosome 9. These observations are: (a) the large size (> 100 kb) of most NSCLC p15/p16 deletions; and (b) the absence of exon 2 mutations in most retained NSCLC p15 and p16 alleles.

Prognostic factors predictive of survival for truncal and retroperitoneal soft-tissue sarcoma

OBJECTIVE

The authors identified prognostic factors relevant to clinical outcomes (especially survival) in truncal and retroperitoneal soft-tissue sarcoma.

SUMMARY BACKGROUND DATA

These results can be used to optimize surgical management and select patients most likely to benefit from novel therapeutic strategies in future trials.

METHODS

A retrospective analysis was performed of a prospectively compiled database of 183 consecutive patients with truncal and retroperitoneal sarcomas seen at the Brigham and Women's Hospital and the Dana Farber Cancer Institute between 1970 to 1994.

RESULTS

For truncal sarcoma, multivariate analysis showed that high-grade histology was associated with an eightfold increased risk of death compared with low-grade histology (p = 0.001). In addition to grade, gross positive margin of resection (p = 0.001), microscopic positive margin (p = 0.023), and tumors greater than 5 cm in size (p = 0.018) were important independent prognostic factors for survival. In this series, postoperative radiation therapy for truncal sarcoma was associated with a 2.4-fold decreased risk of death compared with truncal sarcoma patients receiving no adjuvant radiation therapy, having adjusted for the other prognostic factors (p = 0.030). In contrast, for retroperitoneal sarcoma, multivariate analysis showed that high-grade and intermediate-grade histology were associated with a five- to sixfold increased risk of death compared with low-grade histology (p = 0.009). In addition to grade, gross positive margin of resection (p = 0.001) and microscopic positive margin (p = 0.004) were important independent prognostic factors for survival in retroperitoneal sarcoma. Patients who received either preoperative or postoperative chemotherapy for retroperitoneal sarcoma had a 4.6-fold (p = 0.002) and 3-fold (p = 0.010) increased risk of death, respectively, compared with patients receiving no adjuvant chemotherapy, having adjusted for the other prognostic factors.

CONCLUSIONS

The histologic grade and the margin of resection are prognostic for survival in both truncal and retroperitoneal soft-tissue sarcoma. Tumor size was an independent prognostic factor for truncal sarcoma, but not for retroperitoneal sarcoma. Postoperative adjuvant radiation was beneficial to overall survival for truncal sarcoma. In this series of patients receiving a heterogeneous mixture of chemotherapeutic regimens-either as preoperative "neoadjuvant" therapy or as postoperative "adjuvant" therapy, there were no beneficial effects on survival compared with nonrandomized patients not receiving chemotherapy.

Chromosome aberrations in desmoid tumors. Trisomy 8 may be a predictor of recurrence

Cytogenetic analyses of short-term cultures revealed clonal chromosome aberrations in 6 of 13 desmoid tumors. These aberrations included two consistent events, trisomy 8 (n = 4) and trisomy 20 (n = 3), which have not been reported previously in desmoid tumors. Because trisomy 8 was found in two recurrent desmoid tumors, we used fluorescent in situ hybridization (FISH) methodology to evaluate chromosome 8 in 25 paraffin-embedded and frozen desmoid specimens. The FISH studies demonstrated that both patients with cytogenetic trisomy 8 at the time of recurrence also had had trisomy 8 in primary tumors 4 years earlier. The proportion of trisomy 8 cells in these cases did not change substantially between original diagnosis and recurrence. The FISH studies also revealed trisomy 8 in one recurrent desmoid tumor which had been cytogenetically unremarkable and revealed trisomy 8 in one recurrent desmoid that had not been karyotyped. Four of six patients with trisomy 8 had been followed for more than 1 year, and the desmoid tumors in each of these 4 patients recurred. By contrast, recurrence was noted in only 2 of 17 patients whose desmoid tumors lacked trisomy 8. Our findings demonstrate that trisomy 8 and trisomy 20 are nonrandom aberrations in desmoid tumors. Trisomy 8 appears to be associated with an increased risk of recurrence.

Trimetrexate in malignant mesothelioma: A Cancer and Leukemia Group B Phase II study

PURPOSE

Folic acid antagonists are reported to have activity against mesothelioma. The Cancer and Leukemia Group B (CALGB) undertook this phase II study of the new antifolate, trimetrexate (TMTX), to evaluate its response rate and toxicity in chemotherapy-naive patients with malignant mesothelioma.

PATIENTS AND METHODS

Fifty-two patients were accrued to this protocol. Because of concerns about TMTX toxicity in patients with malignant effusions and/or hypoalbuminemia, the first 17 patients were treated at a dose of 6 mg/m2 daily for 5 days every 21 days. Because minimal toxicity was observed, the subsequent 35 patients were treated at a dose of 10 mg/m2.

RESULTS

Two of 17 patients (12%) in the 6-mg/m2 treatment group had a partial response (PR) and four of 34 eligible patients (12%) in the 10-mg/m2 treatment group had a PR or regression (R) of assessable disease. No patient achieved a complete response (CR). Median survival durations were 5.0 and 8.9 months in the 6- and 10-mg/m2 treatment groups, respectively, while the 2-year survival rates were identical at 18%. At the 10-mg/m2 dose, toxicity was tolerable, with one toxic death from sepsis and a 12% rate of grade 4 thrombocytopenia and granulocytopenia.

CONCLUSION

In this large trial, TMTX showed minor activity in the treatment of malignant mesothelioma. Myelosuppression was mild and dose-related. Future studies of higher doses of TMTX should be considered.

Prognostic factors predictive of survival and local recurrence for extremity soft tissue sarcoma

OBJECTIVE

The authors sought to identify prognostic factors in the management of extremity soft tissue sarcoma.

SUMMARY BACKGROUND DATA

The surgical management of soft tissue sarcoma has evolved because of advances in therapy, resulting in increased limb preservation and quality of life. However, identifying a subset of patients most likely to benefit from adjuvant chemotherapy has been difficult to achieve.

METHODS

A retrospective analysis of a prospective data base of 182 patients with extremity sarcomas from 1970 to 1992 was performed.

RESULTS

A histologic diagnosis of Ewing's sarcoma, synovial sarcoma, and angiosarcoma was associated with a 13-fold increased risk of death compared with liposarcoma, fibrosarcoma, and malignant peripheral nerve sheath histologic types after having adjusted for the other prognostic factors (p < 0.001). In addition to histologic type, high-grade sarcomas (p = 0.018), sarcomas greater than 10 cm in size (p = 0.006), and age at diagnosis (p = 0.016) were found to be important prognostic factors for survival but not for local recurrence. For the first time to their knowledge, the authors showed that mean mitotic activity has prognostic value after having adjusted for other prognostic factors, such as grade (p = 0.005). The only prognostic factors predictive for local recurrence were whether the patient presented with locally recurrent disease (p = 0.0001) or had microscopically positive margins (p = 0.052).

CONCLUSIONS

The use of mitotic activity along with grade, size, histologic type, and age at diagnosis is prognostic for survival in extremity soft tissue sarcoma. The use of an objective pathologic feature, such as mean mitotic activity, is also useful in selecting patients for future systemic neoadjuvant or adjuvant trials and primary therapy.

Cardiac synovial sarcoma with translocation (X;18) associated with asbestos exposure

A primary cardiac spindle cell tumor with immunoreactivity for keratin proteins is reported. Cytogenetic analysis of the tumor demonstrated a translocation (X;18), an aberration almost exclusively reported in synovial sarcomas. Postmortem examination revealed amphibole asbestos within the lungs and diaphragmatic pleural plaques indicative of asbestos exposure. These findings raise questions about the possible causation of this tumor.

Randomized phase II trial of cisplatin with mitomycin or doxorubicin for malignant mesothelioma by the Cancer and Leukemia Group B

PURPOSE

The Cancer and Leukemia Group B (CALGB) conducted a randomized phase II multicenter trial to evaluate the activity of two cisplatin-containing regimens (cisplatin and mitomycin [CM], or cisplatin and doxorubicin [CD]) in patients with malignant pleural or peritoneal mesothelioma (protocol CALGB 8435).

PATIENTS AND METHODS

Seventy-nine patients were entered between June 1984 and October 1986. Eligibility included a performance status of 0 to 2 by CALGB criteria, and no prior chemotherapy. Central pathology review was performed. Randomization was stratified according to the cell type (epithelial v mixed or sarcomatous) and the presence of measurable versus assessable disease. Of the 79 patients entered, 70 were included in this analysis (35 on CM and 35 on CD), including 48 with epithelial cell type and 22 with mixed or sarcomatous cell types. Sixty-six patients had pleural mesothelioma and four had peritoneal mesothelioma. There were 34 cases with measurable disease and 36 with assessable disease.

RESULTS

The overall response rate was 26% for CM (two complete responses [CRs], three partial responses [PRs], and four regressions) and 14% for CD (four PRs and one regression). Median time to treatment failure was 3.6 months for CM and 4.8 months for CD, and median survival duration from study entry was 7.7 and 8.8 months, respectively, with no significant differences between treatments. Good performance status (0 or 1) was associated with significantly longer survival duration (P = .013). Both regimens were well tolerated and there were no treatment-related deaths due to toxicity.

CONCLUSION

Moderate antitumor activity has been observed with both regimens. In this randomized phase II trial, the overall response rates, time to treatment failure, and overall survival appear to be similar for the two regimens tested.

Node status has prognostic significance in the multimodality therapy of diffuse, malignant mesothelioma

PURPOSE

We studied a multimodality approach using extrapleural pneumonectomy, chemotherapy, and radiotherapy in patients with malignant pleural mesothelioma.

PATIENTS AND METHODS

From 1980 to 1992, 52 selected patients, underwent treatment. Median age was 53 years (range, 33 to 69). Initial patient evaluation was performed by a multimodality team. Pathologic diagnosis was reviewed and confirmed before therapy. Patients with no medical contraindication and potentially resectable mesothelioma on computed tomography (CT) (magnetic resonance imaging [MRI] when it became available) received extrapleural pneumonectomy, cyclophosphamide, doxorubicin, and cisplatin (CAP) chemotherapy, and radiotherapy.

RESULTS

Perioperative morbidity and mortality rates were 17% and 5.8%, respectively. The overall median survival duration is 16 months (range, 1 month to 8 years). The 32 patients with epithelial histologic variant had 1-, 2-, and 3-year survival rates of 77%, 50%, and 42%, respectively. Patients with mixed and sarcomatous cell disease had 1- and 2-year survival rates of 45% and 7.5%; no patient lived longer than 25 months (P < .01). At resection, positive regional mediastinal lymph nodes were found in 13. Positive lymph nodes were associated with poorer survival than were negative nodes (P < .01). Patients with epithelial variant and negative mediastinal lymph nodes had a survival rate of 45% at 5 years.

CONCLUSION

Multimodality therapy including extrapleural pneumonectomy has acceptable morbidity and mortality for selected patients. Prolonged survival occurred in patients with epithelial histologic variant and negative mediastinal lymph nodes. These data provide a rationale for a revised staging system for malignant pleural mesothelioma; furthermore, they permit stratification of patients into groups likely to benefit from aggressive multimodality treatment.

Selected benefits of thoracotomy and chemotherapy for sarcoma metastatic to the lung

To determine the benefit of aggressive surgical therapy, we studied 77 consecutive patients presenting to our sarcoma registry with pulmonary metastases. Detailed follow-up was available on all patients; the median follow-up of the 13 long-term survivors was 72 months from the date of diagnosis of the primary tumor. Survival of these 77 patients with metastatic disease was independent of the size, location, and histology of the primary tumor. Once metastases developed, survival of patients with pulmonary metastases was not influenced by the extent of surgical resection of the primary tumor or by the use of radiation therapy. Pulmonary metastases were initially treated with thoracotomy and metastasectomy in 34 patients. The median survival after thoracotomy was 26 months. Seven patients were alive more than 4 years after their diagnosis. Pulmonary metastases were treated with chemotherapy alone in 43 patients. Although the survival was shorter (median survival 14 months) in patients treated with chemotherapy, an objective response to chemotherapy was obtained in 13 (30%) patients. Four of these patients were alive 4 years after their diagnosis. These data demonstrate that both thoracotomy and chemotherapy are associated with long-term survival of patients with sarcoma metastatic to the lung.

Fluorescent in situ hybridization assessment of chromosome 7 copy number in uncultured lung and kidney cells

Trisomy 7 is common in cells cultured from nonneoplastic lung and kidney tissues, but the frequency of trisomy 7 in uncultured lung and kidney has not been determined. In this study, we used fluorescent in situ hybridization (FISH) to assess chromosome 7 copy number in uncultured interphase nuclei from lung and kidney specimens. All specimens had low level mosaicism for trisomy 7(1.5-5.25%), but control experiments indicated a potential wide margin of error in quantifying these events.

Utility of high-resolution ultrasound for the diagnosis of dialysis-related amyloidosis

OBJECTIVE

To evaluate the utility of real-time, high-resolution ultrasound of the shoulder in the diagnosis of dialysis-related amyloidosis.

METHODS

We performed a case series study of 2 groups of patients seen at a referral-based clinic in a tertiary care hospital. The shoulders of 13 patients with normal renal function and of 38 patients receiving long-term hemodialysis were studied by real-time, high-resolution ultrasound. All hemodialysis patients were evaluated clinically for the presence of dialysis-related amyloidosis. Surgical specimens of joints were available for all 13 patients with normal renal function and for 17 of the 38 hemodialysis patients. These specimens were evaluated for the presence of beta 2-microglobulin (beta 2m) amyloid by Congo red and immunohistochemical staining.

RESULTS

Two ultrasonographic findings were selectively observed in the dialysis patients with clinical and histologic evidence of beta 2m amyloid in comparison with patients with normal renal function and no evidence of amyloid: rotator cuffs greater than 8 mm in thickness and echogenic pads between muscle groups of the rotator cuff. The presence of at least 1 of these 2 findings corresponded to the presence of clinically and histologically evident beta 2m amyloid with a sensitivity of 79% and a specificity of 100%. When additional patients without surgical specimens for histologic confirmation of amyloidosis were included, the sensitivity of these 2 sonographic findings was 72% and the specificity was 97%.

CONCLUSION

Real-time, high-resolution ultrasound is a relatively sensitive and highly specific noninvasive adjunct to the clinical diagnosis of beta 2m amyloidosis in patients receiving long-term hemodialysis.

Long-term salvageability for patients with locally recurrent soft-tissue sarcomas

Between 1971 and 1988, 39 patients were referred because of local recurrence of soft-tissue sarcomas and data from their patient records were analyzed to determine the parameters governing local recurrence. Mean follow-up was 11.1 years, with a mean time to local recurrence of 22 months. Twenty-one patients had local recurrence only, without metastatic disease. Salvage was provided for 14 (67%) of these patients after reexcision of local recurrence, and all 14 patients remained free of disease (mean follow-up, 112 months). We conclude that (1) excisional biopsy of tumors larger than 3 cm leads to potential contamination of clean tissue planes, limits ability to achieve an adequate margin of resection, and may compromise the definitive excision, and (2) in patients with local recurrence only, there is a high rate of long-term salvage (67% for follow-up of 9.3 years) after radical compartmental excision with or without postoperative radiation therapy.

Radiographic detection of metal-induced synovitis as a complication of arthroplasty of the knee

Radiographs of eighteen patients who had had a diagnosis of metal-induced synovitis subsequent to a knee-replacement arthroplasty were retrospectively reviewed. The presence of a dense line outlining a portion of the capsule or articular surface of the knee joint (the so-called metal-line sign) was noted in association with wear in eleven patients. In the nine patients who had a positive sign and also had specimens available for histological examination, there was dense deposition of metal particles, whereas in the six patients who did not have a metal-line sign and had specimens available for histological examination, five had only a slight amount of metal in the synovial tissue and one, a moderate amount. The presence of the metal-line sign was associated with metal-induced synovitis in eleven of the eighteen patients. The sign should be useful in helping to make this diagnosis preoperatively in many patients.

Extrapleural pneumonectomy, chemotherapy, and radiotherapy in the treatment of diffuse malignant pleural mesothelioma

Malignant pleural mesothelioma has been considered a uniformly fatal disease associated with a median survival of 4 to 18 months. Extrapleural pneumonectomy alone has proved disappointing in the treatment of this disease, as have chemotherapy and radiotherapy. From 1980 to 1990, 31 patients with pleural mesothelioma underwent multimodality therapy that included extrapleural pneumonectomy with resection of the pericardium and diaphragm. The age of the patients was 53.4 +/- 8.6 years; 26 were male. All patients had the pathologic diagnosis reviewed before treatment. At thoracotomy six patients had residual (unresectable) gross disease, and in 23 there was histologic evidence of disease at the resection margin. The perioperative morbidity and mortality rates were 19% and 6%, respectively. The mean length of hospital stay for the 29 patients who survived the operation was 10.9 +/- 3.5 days. Postoperatively 26 patients received cyclophosphamide, doxorubicin, and cis-platinum chemotherapy with or without radiotherapy. The survival rates were 70% at 1 year and 48% at 2 years. Trends toward improved survival in the patients with complete resections approached but did not reach statistical significance. These data suggest that this multimodality protocol can be administered with acceptable morbidity and mortality. Prospective trials are justified to further clarify the role of this approach.

Diagnosis of diffuse malignant mesothelioma: experience of a US/Canadian Mesothelioma Panel

The experience of the US/Canadian Mesothelioma Panel with its first 200 cases is reviewed. The light microscopic diagnosis, histochemical findings, immunohistochemical findings, and electron microscopic features of malignant mesotheliomas are reviewed in the context of differential diagnosis. Reasons for referral of case material to the panel and lessons from follow-up of difficult and controversial cases are reported. Recommendations to general pathologists are made regarding evaluation and review of possible mesotheliomas.

Diagnostic relevance of clonal cytogenetic aberrations in malignant soft-tissue tumors

BACKGROUND

Malignant soft-tissue tumors often present substantial diagnostic challenges. Chromosome aberrations that might be diagnostic have been identified in some types of soft-tissue tumors, but the overall frequency and diagnostic relevance of these aberrations have not been established.

METHODS

We attempted to determine the karyotypes of a series of 62 consecutive, unselected malignant spindle-cell or small round-cell soft-tissue tumors (from 46 adults and 16 children) after direct harvesting of cells or short-term culture. All tumors were examined independently by immunohistochemical staining in addition to routine light-microscopical evaluation, and all but two tumors were examined by electron microscopy.

RESULTS

Metaphases were obtained from 61 of the 62 tumors, and clonal chromosome aberrations were identified in 55 (89 percent). In the six tumors that yielded metaphases but lacked apparent clonal aberrations, the normal metaphases were found to originate from non-neoplastic stromal elements within the tumor specimens. Thus, all tumors in which karyotyping was successful contained clonal chromosome aberrations. Forty of 62 tumors (65 percent) contained clonal chromosome aberrations that either suggested or confirmed a specific diagnosis; in 15 of these tumors (24 percent of all tumors), the aberrations were important in establishing the final diagnosis. Cytogenetic analyses were particularly informative about small round-cell tumors from children: 8 of 14 round-cell tumors contained diagnostically important chromosome aberrations. Using the combined approaches of light and electron microscopy, immunohistochemistry, and cytogenetics, we established an unambiguous diagnosis for 60 of 62 tumors.

CONCLUSIONS

Cytogenetic analyses reveal clonal chromosome aberrations in virtually all malignant soft-tissue tumors. These clonal chromosome aberrations, particularly in small round-cell tumors in children, often have diagnostic relevance.

Cytogenetic evidence of clonality in a case of pigmented villonodular synovitis

Pigmented villonodular synovitis is an uncommon benign lesion that is characterized by diffuse synovial proliferation. Based on animal models, this lesion has been conjectured previously to be reactive in nature. In this report, the authors present the histologic and cytogenetic findings for a pigmented villonodular synovitis that was excised from the right knee of a 47-year-old man. Trisomy 7 was observed in 24 of 75 (35%) metaphases obtained from short-term culture of cells from this tumor. These findings suggest that some cases of pigmented villonodular synovitis represent clonal, neoplastic proliferations.

Melanoma and soft tissue sarcoma in seven patients

Seven patients with both melanoma and sarcoma were seen at the Dana Farber Cancer Institute (Boston, MA) over a 4-year period. Three had additional malignant neoplasms; one of these patients also had the hereditary cutaneous malignant melanoma, dysplastic nevus syndrome. These observations suggest the possibility of a biologic relationship between melanoma and sarcoma, the nature of which remains unknown.

Hypodense eosinophils and interleukin 5 activity in the blood of patients with the eosinophilia-myalgia syndrome

The recent recognition of the eosinophilia-myalgia syndrome (EMS) associated with the ingestion of L-tryptophan prompted an analysis of the peripheral blood eosinophil phenotypes and of the serum eosinophil hematopoietins in this disorder. Five patients with an illness characterized by the abrupt onset of aching skeletal muscles, edema, thickening and induration of the skin, and marked blood eosinophilia associated with L-tryptophan ingestion provided eosinophils, serum, or both, for evaluation. Gradient sedimentation density analysis of the peripheral blood eosinophils from four of these patients revealed that 43 +/- 13% (mean +/- SEM) of the cells had converted to the abnormal (hypodense) sedimenting phenotype. When normodense eosinophils from the reference donors were cultured for 3 days in medium supplemented with increasing concentrations of serum from the patients with EMS, their viability increased in a dose-dependent manner to 45%, which was significantly augmented over the effect of normal serum. This eosinophil viability-sustaining activity was inhibited by 76 +/- 7% (mean +/- SEM; n = 3) by the addition of anti-interleukin 5 (IL-5) but not by neutralizing antibodies monospecific for either granulocyte/macrophage colony-stimulating factor (GM-CSF) or IL-3. IL-5, an eosinophilopoietic factor, converts normodense peripheral blood eosinophils in vitro to a hypodense sedimenting form with extended viability and augmented biologic responses to activating stimuli. Thus, the presence of IL-5 in the sera of patients with EMS may contribute to the development and maintenance of the eosinophilia and may regulate the conversion of the peripheral blood eosinophils to the hypodense phenotype with augmented pathobiologic potential.

ME1. A monoclonal antibody that distinguishes epithelial-type malignant mesothelioma from pulmonary adenocarcinoma and extrapulmonary malignancies

ME1 is a monoclonal antibody reactive in frozen tissue sections with normal mesothelial cells and malignant mesotheliomas. In this immunoperoxidase study, ME1 reacted with all 40 epithelial type malignant mesotheliomas. Fifty percent or more of the mesothelioma cells were stained in all cases and the staining intensity was strong in 32 and moderate in eight. In contrast, all 19 well- and moderately differentiated pulmonary adenocarcinomas were completely negative, and of the total 88 non-mesotheliomatous malignancies studied, staining comparable to the mesotheliomas was seen in only 6 tumors (2 pulmonary adenocarcinomas, 2 adenocarcinomas of the breast, 1 adenocarcinoma of the pancreas, and 1 melanoma), although limited, weaker staining was seen in additional cases. Five of the six strongly to moderately positive nonmesotheliomatous tumors had immunoreactivity for complementary immunoreactants (CEA, Leu-M1, S-100 protein, HMB-45). Our results with ME1, the first monoclonal antibody that recognizes malignant mesothelial cells, provides a basis for using this reagent in the differential diagnosis of tumors of the pleura and peritoneum.

Carboplatin in malignant mesothelioma: a phase II study of the Cancer and Leukemia Group B

Carboplatin (400 mg/m2) was given at 28-day intervals to 41 patients with malignant mesothelioma. In all, 40 patients were eligible and evaluable for response. Partial responses were seen in 2 cases (5%); regression of evaluable disease, in 1 patient (2%); and stable disease, in 19 subjects (48%). A median of two doses of carboplatin per patient resulted in mild toxicity. Leukopenia (less than or equal to 2,000 cells/microliters) and thrombocytopenia (less than 100,000 cells/microliters) were seen in only 6% and 20% of the patients, respectively. Median survival from study entry was estimated at 7.1 months, with a 1-year survival of 25% +/- 7%. Carboplatin given at a dose of 400 mg/m2 at 28-day intervals shows minor activity against malignant mesothelioma.

Rheumatoid aortitis: a rarely recognized but clinically significant entity

Aortitis as a feature of rheumatoid arthritis is considered rare. We have, however, identified 10 patients with aortitis from among 188 consecutive autopsy cases of rheumatoid arthritis. There were 5 men and 5 women with a mean duration of rheumatoid arthritis of 9.6 years. Nine were rheumatoid factor positive and had associated nodules. In addition to standard treatment regimens, 9 patients received corticosteroids. Although involvement of the thoracic aorta was most common, involvement of both the thoracic and abdominal aorta was present in 4 cases. Two patients had aneurysmal dilatation of the thoracic aorta and 1 of the abdominal aorta. Microscopic features of aortitis included necrosis of medial smooth muscle and elastica, with an inflammatory infiltrate comprising primarily lymphocytes and plasma cells. A panmural aortitis was seen in 3 cases. Rheumatoid granulomas were noted in the aortic wall in 5. The diagnosis of aortitis was not made until autopsy in any case. Aortitis was hemodynamically significant in 3 patients. Two had congestive heart failure secondary to thoracic aortitis and aortic valvulitis, and 1 had rupture of an abdominal aortic aneurysm at a site involved by aortitis. Seven patients had rheumatoid vasculitis with a mean of 10 organs involved. Six of these died of complications directly related to vasculitis, including 4 patients with coronary arteritis and associated myocardial infarction. Aortitis can be a feature of severe rheumatoid arthritis and is often associated with rheumatoid vasculitis. Hemodynamic compromise does occur and may be fatal.

Pulmonary metastases in patients with low-grade endometrial stromal sarcoma. Clinicopathologic findings with immunohistochemical characterization

Two cases of low-grade endometrial stromal sarcoma (ESS) presenting as cystic pulmonary metastases are reported. Both lung lesions were initially thought to represent examples of so-called mesenchymal cystic hamartoma. A diligent search of the past medical records in the first case revealed that a primary low-grade ESS of the uterus had been resected 27 years earlier. In the second case, a uterine tumor was seen by computed tomography scan and subsequent pathologic examination of the hysterectomy specimen established the presence of a low-grade ESS. Peritoneal metastases, present in both cases, also presented diagnostic problems until the uterine primaries were recognized. Immunoreactivity for desmin was detected in all primary and metastatic tumor sites examined. We conclude that ESS should be included among the desmin-positive spindle cell sarcomas and that metastatic ESS should be included in the differential diagnosis of "benign" mesenchymal cystic hamartoma of the lung.

Keratin protein immunoreactivity of sarcomatoid and mixed types of diffuse malignant mesothelioma: an immunoperoxidase study of 30 cases

To define the role of keratin protein immunohistochemistry in the pathologic diagnosis of the sarcomatoid type of diffuse malignant mesothelioma (DMM), we examined 30 DMM (16 pure sarcomatoid type and 14 mixed sarcomatoid-epithelial type) by an indirect immunoperoxidase technique using three commercially available antibodies to keratin proteins. The sarcomatoid (spindle-cell) areas of all 30 cases of sarcomatoid DMM were immunoreactive for keratin proteins. In 14 of 16 cases of sarcomatoid DMM, 50% or more of the tumor cells were reactive with one or more antibodies; however, polyclonal bovine muzzle and monoclonal AE1/AE3 antibodies were distinctly superior to polyclonal human callus keratin antibody in the detection of spindle tumor cells. In contrast with the staining patterns observed for DMM, 39 spindle-cell malignancies and tumor-like processes of 10 histogenetic types were unreactive with the three antibodies. Those spindle-cell tumors and reactive mesothelial proliferations that may enter into the differential diagnosis of sarcomatoid DMM are discussed. We conclude that keratin protein immunohistochemistry is a sensitive and highly useful method for the pathologic diagnosis of the sarcomatoid type of DMM and its distinction from other spindle-cell neoplasms.

Involvement of chromosome X in primary cytogenetic change in human neoplasia: nonrandom translocation in synovial sarcoma

A translocation that involves chromosome X (band p11.2) and chromosome 18 (band q11.2) was observed in short-term in vitro cultures of cells from five synovial sarcomas and one malignant fibrous histiocytoma. In four of these tumors, the translocation t(X;18)(p11.2;q11.2) was reciprocal. The two other tumors had complex translocations: t(X;18;21)(p11.2;q11.2;p13) and t(X;15;18)(p11.2;q23;q11.2). A translocation between chromosomes X and 18 was not detected in other histological types of soft tissue sarcoma. The X;18 rearrangement appears to characterize the synovial sarcoma and is the first description of a primary, nonrandom change in the sex chromosome of a human solid tumor.

The distinction of adenocarcinoma from malignant mesothelioma in cell blocks of effusions: the role of routine mucin histochemistry and immunohistochemical assessment of carcinoembryonic antigen, keratin proteins, epithelial membrane antigen, and milk fat globule-derived antigen

The immunohistochemical profile (i.e., carcinoembryonic antigen, keratin proteins, epithelial membrane antigen, human milk fat globule-derived antigen, and mucin) of paraffin-embedded cell blocks of 20 malignant effusions from patients with malignant mesothelioma was compared with that of 39 malignant effusions from patients with metastatic adenocarcinoma to determine whether these markers distinguished between these tumor types. Twenty-three adenocarcinomas (59 per cent) stained for mucin. Immunoreactivity for carcinoembryonic antigen (CEA) was observed in 28 adenocarcinomas (72 per cent). All were immunoreactive for keratin proteins, and 29 adenocarcinomas (74 per cent), including seven that were mucin and CEA negative and exhibited a "peripheral predominant" staining pattern for keratin proteins. By contrast, none of the mesotheliomas stained for mucin or for CEA, and, although all were immunoreactive for keratin proteins, none demonstrated a peripheral predominant pattern of staining. Epithelial membrane antigen and milk fat globule-derived antigen were identified in the majority of both mesotheliomas and adenocarcinomas. Neither staining intensity nor pattern of reactivity of these markers clearly distinguished the tumors. This study of cell blocks of serous effusions suggests that staining for mucin, immunoreactivity for carcinoembryonic antigen, and a peripheral predominant pattern of reactivity for keratin proteins represent highly characteristic markers of adenocarcinomas, which identify the majority of these tumors (38 of 39) and allow their distinction from malignant mesotheliomas.

Doxorubicin chemotherapy in the treatment of soft-tissue sarcoma. Combined results of two randomized trials

In 1978, there were initiated two independent randomized, prospective trials of adjuvant doxorubicin hydrochloride (Adriamycin) following primary therapy for soft-tissue sarcoma. The virtual identity of these two protocols permits their combination for analysis. A total of 75 patients (42 men, 33 women) with soft-tissue sarcoma (stages IIB to IVA) were randomized, after receiving optimal regional therapy, to receive either doxorubicin hydrochloride (450 mg/m2) (37 patients) or observation (38 patients). Follow-up has ranged from 16 to 80 months (median, 49 months). Twenty-five patients (33%) died, and two patients receiving doxorubicin developed cardiotoxicity. No significant differences in local control, metastasis-free survival, disease-free survival, and overall survival were observed for the two treatment arms. Despite temporary prolongation of disease-free survival with doxorubicin in some subgroups, we conclude that there is no advantage to the use of adjuvant doxorubicin in the treatment of soft-tissue sarcoma.

Early peritoneal mesothelioma: a treatable malignancy

37 patients with malignant peritoneal mesothelioma were studied to assess the efficacy of combined therapy. 14 patients presented after 1982. Of 6 patients treated intensively, all remain alive with no evidence of disease by computed tomographic scan at 9-36 months. Of 8 patients treated palliatively, 5 are dead. (5 had stable disease, 1 has progressed despite all treatment, and 2 were not treated.) Survival of the intensively treated group is significantly better than that of other stage I patients in this series. Patients under 40 had a significantly better survival rate than older patients.

Optimal immunoreactivity of keratin proteins in formalin-fixed, paraffin-embedded tissue requires preliminary trypsinization. An immunoperoxidase study of various tumours using polyclonal and monoclonal antibodies

The effect of preliminary trypsinization on the immunoreactivity of keratin proteins in formalin-fixed, paraffin-embedded tissues of a variety of tumors (squamous cell carcinomas, adenocarcinomas, mesotheliomas, and transitional cell carcinomas) was evaluated. Three types of trypsin (Type II and Type IX porcine trypsin and Type III bovine trypsin) and varying concentrations of trypsin were assessed. Immunoreactivity of keratin proteins was determined using rabbit anti-keratin antibodies and monoclonal antibodies (combination of AE1 and AE3) and immunoperoxidase techniques. Preliminary trypsinization was mandatory for optimal immunoreactivity of keratin proteins using either polyclonal or monoclonal antibodies. Excellent results were obtained using Type II porcine trypsin at concentrations of 25 mg/dl for 30-45 min or 50 mg/dl for 20 min, at 37 degrees C. Trypsin treatment with excessive concentrations of enzyme and/or extended incubation times promoted tissue digestion and in some cases, yielded decreased immunoreactivity and altered staining patterns.

Immunohistochemical localization of smooth muscle myosin in normal human tissues

Immunohistochemical localization of smooth muscle myosin, an immunologically distinct contractile protein, was achieved using rabbit anti-human uterine smooth muscle myosin antibodies. In immunodiffusion studies and in cryostat sections, these antibodies were highly specific and reacted with smooth muscle myosin but not with platelet, skeletal muscle, or cardiac muscle myosin. To evaluate comprehensively the structural profile of smooth muscle elements in normal human tissues, an indirect immunoperoxidase technique (peroxidase-antiperoxidase) was applied to a wide variety of specimens. Parallel studies comparing cryostat sections with fixed (10% formalin, B5, Bouin's, or Zenker's solution) paraffin-embedded tissues revealed optimal immunoreactivity, sensitivity, and specificity of staining for smooth muscle myosin using frozen tissues. Strong immunoreactivity was present in muscular tissues such as blood vessels and the muscularis of gastrointestinal and genitourinary tracts. Distinct delineation of smooth muscle elements, including individual smooth muscle cells, and their specific patterns of alignment and organization, were observed, e.g., cells comprising the muscularis mucosae and extending into the lamina propria of the gastrointestinal tract, and myoepithelial cells of skin, exocrine glands, and breast. This method provides excellent morphologic preservation and readily permits unambiguous identification of individual cells containing smooth muscle myosin.

Benign and malignant pleural mesothelioma

Malignant mesotheliomas have assumed an importance in the medical and lay literature out of proportion to their incidence in the American population, chiefly due to the known association of pleural mesothelioma with asbestos exposure. Data from the Connecticut tumor registry suggest that this tumor is increasing in incidence. Based on exposures between 1940 and approximately 1970, when industrial precautions were first instituted, epidemiologists estimate that the number of new cases of mesothelioma will peak sometime in the 1990s and that mesothelioma will thereafter become less common. These models generally assume that asbestos exposures after 1970 will be insignificant. While industrial levels that are legal today will almost certainly prevent the development of severe asbestosis in most workers, unfortunately a threshold of exposure below which there is no risk of mesothelioma has not been documented. Asbestos continues to be used in floor and ceiling tiles, in automobile brake linings, and in a variety of other products. At the present time, construction workers who maintain or remove asbestos constitute one of a number of groups with continued exposure. The diagnosis of a malignant pleural mesothelioma is not difficult provided that the physicians caring for such a patient consider mesothelioma in the differential diagnosis. Patients present with chest pain or shortness of breath, or both, and the initial chest x-ray film most often reveals a large unilateral pleural effusion. The tumor characteristically remains localized until late in its course, and thus extensive workup at the time of diagnosis is seldom required. Generally, a large piece of tissue obtained via an open biopsy is required for adequate histologic diagnosis. Investigational approaches include taking numerous needle biopsies with samples sent for electron microscopy as well as for immunoperoxidase staining for keratin and CEA. The treatment of this disease remains unsatisfactory. Occasional patients have remained disease-free for periods in excess of 5 years after intensive treatment, however. The conclusion that mesothelioma is untreatable is clearly untenable since palliation and a response rate of 30 per cent to various chemotherapeutic regimens have been reported by a number of investigators. While many authors have advocated supportive care alone because "current treatments have not demonstrated increased survival," we believe patients with mesothelioma should be offered investigational therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

An ultrastructural comparison of mesotheliomas with adenocarcinomas of the lung and breast

The ultrastructural features of 15 mesotheliomas were compared with those of equal numbers of adenocarcinomas of the lung and of the breast in a double-blind study. Combined quantitative and qualitative features were evaluated to provide criteria for distinguishing among these three tumors, which may present as either primary or metastatic pleural tumors. mesotheliomas could be distinguished from adenocarcinomas of the lung by length of microvilli (mean ratios of length to diameter [LDR], 15.7 and 8.7, respectively; P less than 0.01) and content of tonofilaments. Length of microvilli was also useful in distinguishing mesotheliomas from breast adenocarcinomas (mean LDR, 15.7 and 6.9, respectively; P less than 0.001). Adenocarcinomas of the lung could be distinguished from adenocarcinomas of the breast by tonofilament content and the presence of intracytoplasmic lumina. Combined quantitative and qualitative criteria are essential for maximal ultrastructural discrimination among these tumors.

Keratin proteins and carcinoembryonic antigen in synovial sarcomas: an immunohistochemical study of 24 cases

Twenty-four synovial sarcomas were examined for the presence of keratin proteins by an indirect immunoperoxidase method with paraffin-embedded tissues. Keratin proteins were identified in 16 of 24 cases (67 per cent). Both the pseudoglandular and spindle cell areas of all eight of the biphasic synovial sarcomas and the spindle cells of eight of the 16 monophasic synovial sarcomas contained keratin proteins. In spindle cell areas, staining was observed in single cells and small cords and clusters of cells in the absence of cleft formation or other evidence of a pseudoglandular component. The predominant cytologic staining pattern in all cases was peripheral, with localization of staining to the cell membrane or adjacent areas, but diffuse and focal cytoplasmic staining patterns were also observed. No staining for keratin proteins was seen in 101 control cases, including 52 sarcomas of various types. Carcinoembryonic antigen was also identified in four of the 24 synovial sarcomas by an indirect immunoperoxidase technique. The identification of keratin proteins may be helpful in the pathologic diagnosis of synovial sarcoma, particularly the spindle cell monophasic variant.