Comparison of cytogenetic abnormalities and deoxyribonucleic acid ploidy of benign, borderline malignant, and different grades of malignant soft tissue tumors.

BACKGROUND

Both DNA flow cytometry and cytogenetic analysis have been used to study soft tissue tumors. With flow cytometry, the DNA content of a relatively large number of cells can be examined, but cytogenetic analysis gives more detailed information about genomic changes.

EXPERIMENTAL DESIGN

In order to compare the advantages and drawbacks of DNA flow cytometry versus chromosomal analysis, 92 primary or recurrent malignant, 16 borderline malignant, and 13 benign soft tissue tumors were karyotyped after short-term culture. DNA ploidy was determined by flow cytometry of suspensions prepared from frozen or paraffin-embedded samples. From 97 patients, 121 samples were analyzed.

RESULTS

On the basis of the results, four groups were distinguished: DNA-euploid tumors with normal diploid karyotypes (group a) or with abnormal (group b) karyotypes, and DNA-aneuploid tumors with normal (group c) or abnormal (group d) karyotypes. The findings in group b show that structural chromosomal abnormalities or minor numerical aberrations of chromosomes are not detected by DNA flow cytometry. In group c, the finding of tumors with an aneuploid DNA-profile and cells with normal karyotypes is most likely due to overgrowth of fibroblasts during culture and subsequent karyotyping of normal cells.

CONCLUSIONS

The findings show that a) DNA flow cytometry has a higher success rate than karyotyping, b) both techniques are complementary, such that DNA flow cytometry gives an "overview", whereas karyotyping gives more detailed information; comparison of both techniques in individual cases leads to a better understanding of the chromosomal events that occurred during oncogenesis, c) histologically low grade tumors are generally DNA-diploid, but may have an abnormal karyotype, and d) histologically high-grade sarcomas tend to have an aneuploid DNA-profile; they are generally more difficult to karyotype.