DNA content in cervical carcinoma: a flow cytometric assessment of DNA heterogeneity.

The degree of DNA heterogeneity varies between tumors arising in different body sites. Any substantial degree of variability within a given tumor can give rise to significant problems in the interpretation of DNA flow cytometric (FCM) studies. This study was undertaken to evaluate the degree of DNA heterogeneity in cervical carcinomas. A total of 100 3-mm punch biopsies were evaluated from single large cases in 10 sections of cervical carcinoma. Of the 10 tumors, 6 were squamous carcinoma, 1 was an adenocarcinoma, 1 was a mixed small cell and squamous carcinoma, 1 was an adenosquamous cancer, and 1 was a small cell carcinoma with a small area of adenocarcinoma. Adequate histograms were available for 95 (95%) of the samples. Of the 10 cases studied, 9 (90%) revealed homogeneity in the DNA pattern. A solitary case demonstrated heterogeneity in one histogram (nine samples DNA diploid and one sample DNA aneuploid). This case was predominantly small cell undifferentiated carcinoma with focal adenocarcinoma. The area of adenocarcinoma was probably the area that contributed to the heterogeneous FCM pattern. From this study we conclude that for most cervical carcinomas of a specific histologic type there is DNA homogeneity. However, for carcinomas with a mixed morphology, DNA heterogeneity is possible and this must be taken into account in any DNA ploidy studies that include mixed or combined tumors.