Background. This study was designed to evaluate the importance of DNA stem line heterogeneity in determining the malignant potential of esophageal cancer.
Methods. Flow cytometric analysis of intratumor heterogeneity of DNA contents was performed on step-sectioned slices of 57 resected esophageal carcinomas.
Results. DNA stem line heterogeneity, as assessed by DNA content measurements, was present in 25 (44%) tumors; 6 (11%) were a combination of diploid and aneuploid DNA pattern, and 19 (33%) had two or more aneuploid peaks with different DNA contents (multiploid). Of the remaining 32 homogeneous tumors, 4 showed only a diploid DNA pattern in all samples examined, whereas 28 tumors had only the aneuploid pattern. Tumors with the heterogeneous DNA pattern had a significantly higher frequency of lymph node metastasis than did those with the homogeneous DNA pattern (P < 0.05).
Conclusions. For evaluation of the highly malignant potential of esophageal carcinoma by nuclear DNA contents, it is important to identify accurately intratumoral heterogeneity. Because different DNA stem lines were evident in different areas of the lesion, evaluation of multiple specimens from a wide area of each lesion is needed to determine with accuracy the degree of intratumor DNA stem line heterogeneity. Cancer 1993; 723564-70.