Prognostic significance of histologic grade and nuclear expression of beta-catenin in synovial sarcoma

Accuracy of cytological grading of spindle-cell sarcomas

Spindle-cell sarcomas constitute an important component of soft-tissue sarcomas, where accurate grading may be more important than histologic subtype in order to plan treatment strategies and determine prognosis. To evaluate the applicability and accuracy of grading spindle-cell sarcomas on fine-needle aspiration cytology (FNAC) smears, 54 cases of histologically documented spindle-cell sarcomas, consisting of synovial sarcomas (20 cases), neurofibrosarcomas (12 cases), leiomyosarcomas (9 cases), dermatofibrosarcoma protuberans (DFSP; 6 cases), fibrosarcomas (3 cases), hemangiopericytomas (2 cases), and spindle-cell sarcomas, unclassified (2 cases), were graded according to a three-tier system proposed earlier for FNAC smears, while the histological sections were graded using the French Federation of National Cancer Centers (FNCLCC) grading system. The cytological grading was correlated with the histological grade. There was an overall cytologic and histologic concordance in 40/54 (74%) cases, and concordance in 9/13 (69%) grade I, 19/25 (76%) grade II, and 12/16 (75%) grade III cases. Analysis of grading of individual sarcomas revealed a concordance in 92% of neurofibrosarcomas, 78% of leiomyosarcomas, 70% of synovial sarcomas, 67% of dermatofibrosarcoma protuberans, 67% of fibrosarcomas, 50% of hemangiopericytomas, and 50% of cases of malignant mesenchymal tumors, spindle-cell type unclassified. Major noncorrelation was seen in 10/54 (18.5%) cases. Minor noncorrelation was seen in 4/54 (7.4%) cases. Thus it is possible to accurately predict the grade in 74% of cases of spindle-cell sarcomas. The cytological and histological concordance was better (75%) in high-grade (grades II and III) as compared to grade I sarcomas (69%). Sampling errors due to morphologic heterogeneity in sarcomas may cause noncorrelation in a few cases.

Cytoplasmic and/or nuclear accumulation of the beta-catenin protein is a frequent event in human osteosarcoma

The molecular events that precede the development of osteosarcoma, the most common primary malignancy of bone, are unclear, and concurrent molecular and genetic alterations associated with its pathogenesis have yet to be identified. Recent studies suggest that activation of beta-catenin signaling may play an important role in human tumorigenesis. To investigate the potential role of beta-catenin deregulation in human osteosarcoma, we analyzed a panel of 47 osteosarcoma samples for beta-catenin accumulation using immunohistochemistry. Potential activating mutations were investigated by sequencing exon 3 of the beta-catenin gene in genomic DNA isolated from tumor samples. Our findings revealed cytoplasmic and/or nuclear accumulation of beta-catenin in 33 of 47 samples (70.2%); however, mutation analysis failed to detect any genetic alterations within exon 3, suggesting that other regulatory mechanisms may play an important role in activating beta-catenin signaling in osteosarcoma. In our survival analysis, beta-catenin deregulation conferred a hazard ratio of 1.05, indicating that beta-catenin accumulation does not appear to be of prognostic value for osteosarcoma patients. When analyzed against other clinicopathologic parameters, beta-catenin accumulation correlated only with younger age at presentation (26.4 vs. 39.8 years). Nevertheless, our results demonstrate that the deregulation of beta-catenin signaling is a common occurrence in osteosarcoma that is implicated in the pathogenesis of osteosarcoma.

Prognostic significance of grading and staging systems using MIB-1 score in adult patients with soft tissue sarcoma of the extremities and trunk

BACKGROUND

The predictive value of histologic grading and staging systems for overall survival in different types of adult soft tissue sarcoma of the extremities and trunk is unclear.

METHODS

Histologic slides from 193 patients with primary tumors were reviewed for diagnosis, and Ki-67 (MIB-1) immunostaining was performed for grading in all patients. Univariate and multivariate analyses were conducted to analyze the results from patients with soft tissue sarcomas as a group and among the six main histologic categories: malignant fibrous histiocytoma (n = 49 patients), liposarcoma (n = 48 patients), synovial sarcoma (n = 30 patients), spindle cell sarcoma (n = 24 patients), small round cell sarcoma (n = 15 patients), and others (n = 27 patients). The median follow-up was 50 months.

RESULTS

Univariate analysis of soft tissue sarcomas showed that tumor size and depth, histologic type, MIB-1 score, grades based on three criteria (tumor differentiation/histologic type, necrosis, and either mitosis or MIB-1 score) and disease stage, as assessed by tumor size, depth, and grade, were associated with overall survival. Among these variables, grading and staging systems using the MIB-1 score had better predictive value compared with the MIB-1 score and standard grading and staging models in the main histologic categories. Because survival curves for the different tumor grades and stages showed similar trends between the different histologic types, multivariate analysis was conducted adjusting for age, gender, disease site, surgical margin, tumor size and depth, grade, stage, and histologic type. Consequently, Grade 3 emerged as the most significant adverse prognostic factor. Additional adverse prognostic factors were Stage III, Grade 2, a histologic type of spindle cell sarcoma, and patient age > 50 years at the time of presentation. The histologic type liposarcoma was identified as a favorable prognostic factor.

CONCLUSIONS

The current results indicate that grading and staging systems using the MIB-1 score are very strong prognostic factors in patients with the main histologic types of soft tissue sarcoma. Specific assessment of histologic type should be carried out before deciding on treatment strategies.

The E-cadherin cell-cell adhesion complex and lung cancer invasion, metastasis, and prognosis

BACKGROUND

Lung cancer is the most common cause of cancer deaths in the western world. Progress in treatment results has been limited, and the prognosis is poor with a 5-year survival less than 15%. Based on new developments in molecular biology, our knowledge about lung carcinogenesis and mechanisms for invasion and metastasis has expanded and may in the future lead to more specific targeted therapies and better prognosis. The E-cadherin-catenin complex is critical for intercellular adhesiveness and maintenance of normal and malignant tissue architecture. Reduced expression of this complex in malignant disease is associated with tumour invasion, metastasis, and unfavorable prognosis.

METHODS

This review is based on search in the Medline database from 1991 to 2001. We have reviewed the relevance of the E-cadherin-catenin adhesion complex in malignancy in general and lung cancer in particular. Furthermore, its role as target for specific therapy is discussed.

RESULTS

Available data indicate that alterations of proteins involved in the E-cadherin-catenin complex are early incidents in cancer development. Reduced or altered expression of one or more of the components in this complex is associated with extended invasive and progressive behavior of cancer cells. Consistently, the E-cadherin-catenin complex appears to be increasingly delicate with regard to cancer prognosis. beta-Catenin, one of the components of the adhesion complex, also plays a significant role in cell signal transduction, gene activation, apoptosis inhibition, and increased cellular proliferation and migration.

CONCLUSION

Inactivation of the E-cadherin-catenin adhesion complex, induced by genetic and epigenetic events, plays a significant role in multistage carcinogenesis, and seems to be associated with dedifferentiation, local invasion, regional metastasis, and reduced survival in lung cancer.

APC mutations in synovial sarcoma

It has previously been demonstrated that accumulated beta-catenin serves as an oncoprotein in synovial sarcoma and results in a poor overall survival rate, but the frequency of beta-catenin mutation was quite low (8.2%). The present study, using essentially the same study group of cases, screened for genetic alterations in the mutation cluster region (MCR) of the APC gene in 49 cases of synovial sarcoma. SSCP analysis followed by DNA direct sequencing revealed five missense APC mutations in four cases of synovial sarcoma (8.2%). The mutational sites comprised one case each at codons 1299 (GCT to ACT, Ala to Thr), 1412 (GGA to AGA, Gly to Arg), and 1414 (GTA to ATA, Val to Ile), in addition to one case with double point mutations at codon 1398 (AGT to AAT, Ser to Asn) and at codon 1413 (ATG to ATA, Met to Ile), together with beta-catenin mutation at codon 32 (GAC to TAC, Asp to Tyr). All four cases with APC mutations were histologically of the monophasic fibrous type and showed beta-catenin accumulation. All three cases with APC mutations available for follow-up data were long survivors. This study provides the first evidence that APC mutations also occur in the field of sarcoma, especially in synovial sarcoma.

Validity and reproducibility of histologic diagnosis and grading for adult soft-tissue sarcomas

Soft-tissue sarcomas in adults show great variations in histologic type and grade. A valid and reproducible prognostication system is needed to select patients with soft-tissue sarcomas who could benefit from adjuvant chemotherapy. This study was conducted to assess the validity and reproducibility of diagnosis of the histologic type, MIB-1 grade, and mitosis grade, as well as of the 3 components of these grading systems. MIB-1 grade is a recently proposed grading system for predicting the prognosis of patients with adult soft-tissue sarcomas on the basis of 3 criteria (tumor differentiation, necrosis, and MIB-1 score) and replaces the mitotic count in the French system with MIB-1 immunohistochemical staining. Four surgical pathologists from 4 institutions who had experience in diagnostic soft-tissue tumor pathology reviewed 130 cases of soft-tissue sarcoma and independently determined histologic type and grade. The validity of histologic diagnosis was measured by sensitivity and specificity, and that of grading was measured by kappa statistics and percentage agreement with the diagnosis of the expert panel at the National Cancer Center, which was defined as a gold standard. Interobserver reproducibility was measured by kappa and by percentage agreement between the diagnoses of the 4 pathologists. The validity of the diagnosis of histologic type was high for synovial sarcoma, small round-cell sarcoma, and liposarcoma (sensitivity 89% to 100%; specificity, 98% to 100%) but low for malignant fibrous histiocytoma (MFH) and spindle-cell sarcoma (73% to 75%; 93% to 95%). For the grading, the validity of the MIB-1 grade was substantial (kappa = 0.68; agreement, 79%) and higher than that of the mitosis grade (0.54; 69%). The most valid component was tumor differentiation (kappa = 0.79), followed by tumor necrosis (0.66), MIB-1 score (0.59), and mitotic score (0.37). Interobserver reproducibility of histologic diagnosis was high for small round-cell sarcoma, synovial sarcoma, and liposarcoma (kappa = 0.92, 0.90, 0.87; percentage agreement = 99%, 97%, 96%, respectively); for grading, reproducibility was highest for tumor differentiation (0.78; 87%) and second highest for MIB-1 grade (0.68; 79%). We conclude that diagnosis of the type of soft-tissue sarcoma for synovial sarcoma, small round-cell sarcoma, and liposarcoma and the MIB-1 grading system based on tumor differentiation are highly valid and reproducible among Japanese pathologists who are familiar with the grading system, whereas re-evaluation of histologic criteria is essential for other histologic types such as MFH and spindle-cell sarcoma.