Search

Data regarding DNA content parameters in soft tissue sarcoma is limited. Development and optimization of tissue specific preparative techniques for DNA flow cytometry was undertaken prior to routine DNA content analysis of soft tissue neoplasms; 154 soft tissue tumors were studied. Dissociation dependent differences in cellular yields, viabilities, maintenance of DNA aneuploid populations, coefficients of variation, and DNA index supported the need for these developmental studies. Fifty-six of eighty-nine patients had DNA aneuploid soft tissue sarcomas. A relationship between DNA aneuploidy and grade was seen in this series with 38% with low grade, 59% with moderate grade, and 69% with high grade tumors demonstrating DNA aneuploid populations (P < 0.005). The mean S-phase fraction for DNA diploid and aneuploid sarcomas was 7.2% and 13.3%, respectively (P < 0.001). When classified by histologic grade of the primary tumor, a greater percentage of metastatic lesions were DNA aneuploid (4 of 7 grade 2 lesions, and 15 of 16 grade 3 lesions). Decreases in cellular yields and rate of DNA aneuploidy were observed in a subgroup of patients with localized high grade sarcoma treated preoperatively, as compared to patients treated with initial surgery. Prospective correlation of DNA content parameters to prognosis and response to cytotoxic therapy are now possible and are ongoing.

DNA content analysis of formalin fixed paraffin embedded (FFPE) tissue permits determination of the influence of DNA content on the prognosis in cohorts of patients for whom the clinical outcome is known. Of key importance in such an analysis is the accuracy of DNA content determination. Variations in the quality of DNA histograms from FFPE tissues of different types prompted a comparative evaluation of the preparative methodology of FFPE soft tissue sarcomas for DNA flow cytometry. Following deparaffination and rehydration of fixed tissue, and prior to fluorochrome staining, tissue blocks of 15 DNA aneuploid soft tissue sarcomas were subjected to repeated experimental (time x concentration) enzyme exposures. The goal of these studies was to define the optimal tissue specific retrieval technique with the coefficient of variation, maintenance of DNA aneuploidy, and DNA index as endpoints. After optimizing the technique, the DNA content of 50 soft tissue neoplasms derived from FFPE specimens was compared to the corresponding fresh surgical tissue. The observed 14 percent error rate in the determination of DNA ploidy status suggest limited utility for FFPE tissue in prospective therapeutic trials of soft tissue sarcoma.