S-phase fraction of 155 soft tissue sarcomas: correlation with clinical outcome

Characterization of a novel radiation-induced sarcoma cell line

BACKGROUND

Radiation-induced sarcoma (RIS) is a potential complication of cancer treatment. No widely available cell line models exist to facilitate studies of RIS.

METHODS

We derived a spontaneously immortalized primary human cell line, UACC-SARC1, from a RIS.

RESULTS

Short tandem repeat (STR) profiling of UACC-SARC1 was virtually identical to its parental tumor. Immunohistochemistry (IHC) analysis of the tumor and immunocytochemistry (ICC) analysis of UACC-SARC1 revealed shared expression of vimentin, osteonectin, CD68, Ki67 and PTEN but tumor-restricted expression of the histiocyte markers α1-antitrypsin and α1-antichymotrypsin. Karyotyping of the tumor demonstrated aneuploidy. Comparative genomic hybridization (CGH) provided direct genetic comparison between the tumor and UACC-SARC1. Sequencing of 740 mutation hotspots revealed no mutations in UACC-SARC1 nor in the tumor. NOD/SCID gamma mouse xenografts demonstrated tumor formation and metastasis. Clonogenicity assays demonstrated that 90% of single cells produced viable colonies. NOD/SCID gamma mice produced useful patient-derived xenografts for orthotopic or metastatic models.

CONCLUSION

Our novel RIS strain constitutes a useful tool for pre-clinical studies of this rare, aggressive disease. UACC-SARC1 is an aneuploid cell line with complex genomics lacking common oncogenes or tumor suppressor genes as drivers of its biology. The UACC-SARC1 cell line will enable further studies of the drivers of RIS.

Prognostic value of proliferation in pleomorphic soft tissue sarcomas: a new look at an old measure

Though proliferation has repeatedly shown a prognostic role in sarcomas, it has not reached clinical application. We performed a comprehensive evaluation of the prognostic role of 5 proliferation measures in a large series of soft tissue sarcomas of the extremities and the trunk wall. One hundred ninety-six primary soft tissue sarcomas of the extremities and the trunk wall were subjected to DNA flow cytometry for quantification of S-phase fraction and to immunohistochemical evaluation of Ki-67, Top2a, p21, and p27Kip1. In univariate analysis, positive expression of Ki-67 (hazard ratio = 4.5, CI = 1.6-12.1), Top2a (hazard ratio = 2.2, CI = 1.2-3.5) and high S-phase fraction (hazard ratio = 1.8, CI = 1.2-3.7) significantly correlated with risk for metastasis. When combined with currently used prognostic factors, Ki-67, S-phase fraction and Top2a fraction contributed to refined identification of prognostic risk groups. Proliferation, as assessed by expression of Ki-67 and Top2a and evaluation of S-phase fraction and applied to statistical decision-tree models, provides prognostic information in soft tissue sarcomas of the extremity and trunk wall. Though proliferation contributes independently to currently applied prognosticators, its role is particularly strong when few other factors are available, which suggests a role in preoperative decision-making related to identification of high-risk individuals who would benefit from neoadjuvant therapy.

The clinical value of flow cytometric DNA content analysis in patients with soft tissue sarcomas

Purpose. The purpose of this study was to evaluate: (1) the correlation between grade and ploidy or S-phase fraction (SPF), (2) the prognostic value of DNA flow cytometric study in soft tissue sarcomas.

Patients /Methods. In all, 47 tissue samples from soft tissue sarcoma patients, surgically treated in the same center, were included. Flow cytometric analyses were performed according to a modified version of the original method of Hedley et al.

Results. DNA ploidy status could be determined in 44 samples out of 47 (success rate 94%). Of these 44, S-phase fraction could be calculated in 34 samples (77%). In the study group as a whole, aneuploidy was significantly correlated with high grade. Survival analyses were carried out in 21 patients with soft tissue sarcoma, all surgically treated in the same center, without chemotherapy or radiotherapy. In univariate analyses, DNA ploidy was found to be a significant factor for overall survival (OAS) and metastasis-free survival MFS. Mean OAS for aneuploid tumors and diploid tumors were 35 and 65 months (p=0.034), and mean MFS 23 and 61 months, respectively (p=0.005) .

Discussion.There is a relation between histological grade and ploidy in soft tissue sarcomas. It appears that low-grade tumors are generally diploid, whereas high-grade tumors tend to be aneuploid. In a subgroup of patients treated only with surgery, DNA ploidy was found to be an important factor for predicting OAS and MFS.

Prognostic Value of CD40 in Adult Soft Tissue Sarcomas

PURPOSE

The purpose is to evaluate the expression of CD40, a membrane protein predominantly expressed on B cells, dendritic cells, and macrophages, in a series of adult soft tissue sarcomas and to test its possible prognostic value.

EXPERIMENTAL DESIGN

CD40 expression was studied by immunohistochemistry. Correlations with other baseline characteristics of patients and tumors were analyzed with chi(2) test. The prognostic value was studied with univariable and multivariable analysis adjusted by age, sex, tumor size, grade, location, and distant metastases.

RESULTS

Eighty-two patients, between January 1994 and May 2001, were analyzed. Membrane or cytoplasmic staining for CD40 protein was absent in 30% of the tumors but present in <10% of cells in 22 (27%), in 10% to 50% in 23 (28%), and in >50% of cells in 12 (15%) tumors. There was no correlation between CD40 expression and age, sex, size, grade, and location of the primary tumor and distant metastases. With 61 patients (74.4%) progressed and 31 (37.8%) dead, CD40 expression was a significant prognostic factor for disease-free and overall survival at univariable and multivariable analysis. Patients with tumors expressing CD40 in >50% of cells had a dramatically unfavorable prognosis with median disease-free and overall survival of 7 and 17 months, respectively, and hazard ratios of relapse and death as compared with patients with CD40-negative tumors of 2.89 (95% confidence interval: 1.26-6.60) and 6.92 (95% confidence interval: 2.18-22.0), respectively.

CONCLUSIONS

These data suggest that expression of CD40 protein in >50% of cells might indicate an unfavorable prognosis in adult soft tissue sarcomas.

Tissue microarray technique in soft tissue sarcoma: immunohistochemical Ki-67 expression in malignant fibrous histiocytoma

Malignant fibrous histiocytoma (MFH) represents a heterogeneous soft tissue sarcoma entity. The authors compared different methods to determine immunohistochemical staining in whole tissue sections, evaluated the tissue microarray technique, and assessed immunohistochemical heterogeneity using the proliferation marker Ki-67 in 47 histopathologic tumor blocks from 11 MFHs. Whole tissue sections were assessed counting 400 cells along a line and counting all cells in 10 high-power fields (0.16 mm2) with mean Ki-67 expression levels of 13% and 11%, respectively. For the tissue microarray technique, two to three 0.6-mm diameter biopsies were studied from each of the 47 tumor blocks. Good correlation was obtained between whole tissue immunohistochemistry and tissue microarray with the microarray method, giving on average 8.6% greater Ki-67 expression levels than the reference method. Immunohistochemical tumor heterogeneity, evaluated using the high-power field method, showed a median standard deviation of 2.3% within the tumor blocks and 2.5% between the blocks from the same tumor. The authors concluded that the tissue microarray technique yields good quality staining and expression levels for Ki-67 comparable with whole tissue methods in MFH, but because of tumor heterogeneity, several tumor blocks ideally should be studied and, because of loss of material in the microarray process, multiple biopsies should be taken. The feasibility of tissue microarray for immunohistochemical studies of soft tissue sarcomas offers new possibilities to study multiple markers in large tumor materials.

The adhesion molecule CD44v6 is associated with a high risk for local recurrence in adult soft tissue sarcomas

In many malignant diseases the expression levels of CD44 and its splice variant v6 (CD44v6) have been associated with the prognosis. The purpose of this study was to investigate the clinical significance of CD44 in adult soft tissue sarcomas (STS). 133 STS patients with a limb or superficial trunk tumour treated at the Helsinki University Central Hospital in 1987-1993 with a median follow-up time of 68 months were included in this study. The expression of CD44 and CD44v6 was determined immunohistochemically on paraffin-embedded tumour samples. 95% of the tumours expressed CD44 and CD44v6 was detected in 57%. Strong CD44 expression was associated with low grade (P = 0.04) and small tumour size (P = 0.02). In diploid tumours the CD44 expression was correlated with low S-phase fraction (P = 0.001). High expression of both, CD44 in general as well as that of CD44v6, predicted a higher risk for local recurrence (CD44: P = 0.01 and CD44v6: P = 0.05). Low CD44v6 content of the primary tumour correlated with poor survival (P = 0.02). Determining the expression of CD44 or CD44v6 in a primary STS could be a valuable tool for selecting the group of patients who might benefit from intensified local tumour treatment.

New diagnostic modalities in soft tissue sarcoma

Molecular and cytogenetic analysis of soft tissue sarcoma has provided a vast amount of new genetic information over the past 10 years. Recent advances in genetic technology, such as fluorescence in situ hybridization (FISH), reverse transcriptase-polymerase chain reaction (RT-PCR), and positional cloning techniques have greatly increased the rate of new discoveries and soon may bring cytogenetic and molecular analysis to standard pathology laboratories. Karotypic analysis of soft tissue tumors have demonstrated specific cytogenetic aberrations which have proved to be extremely useful diagnostically and have solidified and improved soft tissue tumor classification systems. Objective and reproducible prognostication in soft tissue sarcoma remains problematic. Presently, the grade and size of the sarcoma are the most important factors used to estimate risk of relapse and overall survival. Assigning a pathologic grade to an individual sarcoma as a means of predicting clinical behavior is often difficult with a 40% discordance rate even between expert sarcoma pathologists. There is mounting evidence that the composition of membrane phospholipid in tumor tissue is an important indicator of a tumor's cellularity, proliferative capacity, and differentiation state. However, there is a lack of information on the biochemical determinants of sarcoma proliferation and differentiation. To address these problems, novel quantitative ex vivo nuclear magnetic resonance (NMR) methods have been applied to determine the biochemical changes in tissue lipid for soft tissue sarcoma. The biochemical changes in tissue lipid have been found to correlate with sarcoma cellularity, growth rate, and differentiation. Continued prospective NMR analysis of tissue lipid biochemistry in soft tissue tumors will permit the development of a clinically relevant biochemical system of prognostic determinants for soft tissue sarcoma in the future.

Soft tissue sarcoma in adults

Soft tissue sarcomas are a heterogeneous group of tumors, consisting of numerous histiotypes that all share a putative common mesenchymal origin. Although prognosis of these tumors is determined by clinical parameters (size, location, and resection margin status) and pathologic features (mitotic activity and necrosis), the histologic subtype has never been shown to be a consistent independent prognostic factor. Some relevant differences among these histiotypes are emerging, in specific biological parameters such as proliferation indices, in integrin expression profiles, and with regard to drug sensitivity. Several biological factors are considered to be prognostically important. Most attention is directed to regulators of cell-cycle progression. The significance of p53 dysregulation is confirmed by the inhibition of cellular proliferation, both in in-vitro and in in-vivo sarcoma models, after reintroduction of wild type p53. A multidisciplinary approach is essential for the optimal treatment of soft tissue sarcomas. Multimodality treatment has led to a patient-tailored approach with limb-sparing resections integrated with external and/or interstitial irradiation. The value of chemotherapy both in the neoadjuvant and the adjuvant setting, although of critical value in other sarcomas such as Ewing's sarcoma and osteosarcoma, remains to be established for soft tissue sarcomas.

Prognostic implications of various models for calculation of S-phase fraction in 259 patients with soft tissue sarcoma

The S-phase fraction (SPF) in flow cytometric DNA histograms in soft tissue sarcoma (STS) can be calculated in various ways. The traditional planimetric method of Baisch has been shown to be prognostic, but is hampered by a failure rate of around 40%. We therefore tested other models to see if this rate could be decreased with retained prognostic value. In 259 STS of the locomotor system the SPF was calculated according to Baisch and with commercial parametric MultiCycle software using different corrections for background. Using the Baisch model, 159 histograms could be evaluated for SPF. The 5-year metastasis-free survival rate (MFSR) was 0.94 for the low-risk group (defined with SPF), and 0.53 for the high-risk group. In the low-risk group, four of the seven patients who developed metastasis did so after 5 years Using the MultiCycle software, SPF could be calculated in 253 tumours. Depending on type of background correction used, the 5-year MFSR varied between 0.67 and 0.82 for the low-risk group, and between 0.47 and 0.53 for the high-risk group. The late metastasis pattern in the low-risk group was never seen using the MultiCycle software. We conclude that in paraffin archival material, calculation of SPF according to Baisch is preferable in clinical use due to better separation between low-risk and high-risk groups, and also the possibility to identify patients who metastasize late.

Comparison of the Ki-67 score and S-phase fraction as prognostic variables in soft-tissue sarcoma

Immunohistochemically determined Ki-67 scores and flow cytometrically determined S-phase fractions were successfully evaluated from the primary tumours of 123 patients with soft-tissue sarcoma. All patients had either limb or superficial trunk tumours. Ki-67 score correlated strongly with ploidy, S-phase fraction and grade. Ki-67 did not correlate with the size of the primary tumour. When analysed as a continuous variable, Ki-67 was a stronger predictor of both metastasis-free survival and disease-specific overall survival (P = 0.003 and 0.04 respectively) than was the S-phase fraction (P = 0.06 and 0.07 respectively). We tested the relevance of different cut-point values by dividing the whole material into two parts at every 10% (e.g. 10% of patients vs. the remaining 90%, 20% vs. 80%, etc.). We counted the relative risk and confidence interval at all these cut-off points. Ki-67 had good prognostic discriminating power irrespective of the cut-point value, but S-phase fraction lost its prognostic power at higher cut-point values. In conclusion, we found that Ki-67 is a useful prognostic tool in the treatment of soft-tissue sarcoma patients irrespective of the cut-point value. S-phase fraction can be used at lower cut-point values.

Tenascin-C expression in invasion border of early breast cancer: a predictor of local and distant recurrence

We have recently demonstrated an association between distant metastasis and the expression of the extracellular matrix glycoprotein tenascin-C (Tn-C) in the invasion border of small axillary node-negative breast carcinomas. Our purpose was to assess the relationship between the expression of Tn-C in the tumour invasion border and several histopathological and biological variables and to compare their usefulness in predicting local and distant disease recurrences. The original patient group consisted of 143 women with axillary node-negative breast cancer (one bilateral) treated with breast-conserving surgery and post-operative radiotherapy, and followed for a median of 8 years. Because of the small number of recurrences an additional group of 15 similarly treated women with recurrent breast cancer was also studied. The size of the tumour, its histology, including a possible intraductal component, and grade were re-evaluated. The expression of erbB-2, p53, Ki-67 and Tn-C was evaluated by immunohistochemistry. Ploidy and S-phase fraction (SPF) were assessed by flow cytometry. The only statistically significant prognostic factor for local recurrence was Tn-C expression in the invasion border. For metastasis Ki-67 positivity, tumour size and Tn-C expression in the invasion border were statistically significant, but Ki-67 positivity was the only independent prognostic factor. Tn-C expression in the invasion border was associated with a higher proliferation rate measured by Ki-67 and SPF, which is consistent with the suggested growth-promoting activity of Tn-C. Tn-C may be a useful marker in selecting patients for adjuvant therapies to reduce the rate of both local and distant cancer recurrences.

Clinical outcome of patients with previously untreated soft tissue sarcomas in relation to tumor grade, DNA ploidy and karyotype

The most important prognostic factor in soft tissue sarcomas (STS) is tumor grade. Since most grading methods are subject to the interpretation of the individual pathologist, there is a need for objective criteria such as DNA ploidy and karyotype, which are of prognostic value in several types of malignancy. We have analyzed the relationships among tumor grade, DNA ploidy, cytogenetic abnormalities and the clinical outcome of 44 previously untreated patients with 12 different histological types of primary STS. The tumors were graded according to the method of Coindre, which resulted in 9 grade I (20%), 18 grade II (41%) and 17 grade III (39%) STS. DNA flow cytometry and chromosomal analysis were performed using standard techniques. After a median follow-up time of 39 (range, 2-124) months, Kaplan-Meier survival analysis was performed. Significant differences in 5-year overall survival were found between patients with grade I or II and grade III STS (p < 0.05). Seventeen STS were aneuploid and 26 were euploid. In 21 of 39 successfully cultured STS an abnormal karyotype was found. There were no significant differences in survival in relation to DNA ploidy or the presence of chromosomal abnormalities. Our results show that grading had higher prognostic value than DNA ploidy or the presence of cytogenetic abnormalities in this heterogeneous group of STS.

Flow cytometric DNA content analysis of 185 soft tissue neoplasms indicates that S-phase fraction is a prognostic factor for sarcomas. French Federation of Cancer Centers (FNCLCC) Sarcoma Group

BACKGROUND

The authors determined the flow cytometric (FCM) DNA characteristics of 53 benign tumors and 132 malignant (71 primary, 61 recurrent) soft tissue sarcomas to investigate their heterogeneity and to evaluate the prognostic values of DNA ploidy status and S-phase fraction (SPF).

METHODS

One to 11 frozen samples were collected from 185 tumors at 10 participating centers of the French Federation of Cancer Centers (FNCLCC). All FCM analyses were performed in the same laboratory. Histologic diagnoses were collegially reviewed, and grade was assessed by the pathologists of the FNCLCC Sarcoma Group. Relationships between FCM, clinical, and pathologic data were investigated using univariate and multivariate analyses for risks of mortality and metastasis.

RESULTS

All except 2 of the 53 benign lesions were DNA diploid. One schwannoma and one desmoid tumor exhibited small abnormal DNA peaks. SPF was low in all benign lesions. One-third of the sarcomas were DNA diploid, whereas two-thirds were DNA aneuploid. Relationships were found between aneuploidy and mitotic count, grade, and histologic subtype of malignant fibrous histiocytoma. DNA ploidy status did not influence the clinical outcome. Multiple sampling performed in 32 sarcomas showed both diploid and aneuploid samples in 6 tumors. Heterogeneity was related to tumor size. SPF evaluated in 85 sarcomas was related to DNA ploidy status, mitotic count, and grade. SPF > or = 4% was significantly associated with a low overall survival rate. In a multivariate analysis performed for the whole group of 132 patients, the single factors with independent prognostic value for patient mortality were disease free status after the treatment course (P < 0.0001) and SPF (P = 0.03). In the subgroup of patients who were initially free of metastases and free of tumor after the treatment course, SPF remained the only factor that significantly influenced the overall survival rate (P = 0.021).

CONCLUSIONS

Despite its high failure rate, SPF is an independent factor in the prognosis of soft tissue sarcoma and should be considered when patients with a high mortality risk need to be selected for adjuvant chemotherapy.